JP2001021028A - Shift control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out releasing side control of a frictional engaging element with good accuracy by detecting indicating pressure before a prescribed time from a time point judging a critical condition as an indicating pressure corresponding to the critical condition. SOLUTION: In a shift control device for an automatic transmission for shifting by replace of friction engaging elements which simultaneously carry out fastening control and releasing control of friction engaging elements which are different from each other, a critical condition of a release side friction engaging element is judged while gradually reducing indicating pressure of a releasing side friction engaging element on the basis of shift judgment. Indicating pressure before a prescribe time from a time point judged the critical condition is detected as indicating pressure corresponding the critical condition, and release side control of the release side friction engaging element is carried out serving the indicating pressure corresponding to the critical condition as a reference. Even if critical judgment is delayed more than an actual critical condition, the indicating pressure corresponding to the critical condition can be detected with good accuracy, and release control of the release side friction engaging element can be carried out with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly, to a shift control by changing a friction engagement element that simultaneously performs engagement control and release control of different friction engagement elements. Device.

[0002]

2. Description of the Related Art Conventionally, there has been provided an automatic control system in which the engagement and release of a friction engagement element is controlled by hydraulic pressure, and the engagement and release control of two friction engagement elements are simultaneously performed to perform a shift. Transmissions are known.

In the system disclosed in Japanese Patent Application Laid-Open No. Hei 6-341526, when the shift downshift is performed, the hydraulic pressure on the engagement side is made to stand by at a predetermined low pressure, and when the input rotation speed of the transmission reaches the synchronization point of the low speed stage, While the pressure is raised from the predetermined low pressure, the hydraulic pressure on the release side is drained when a predetermined time has elapsed from the synchronization, and the predetermined time is changed according to the input torque and the oil temperature of the transmission. It has a configuration.

[0004] In addition, in Japanese Unexamined Patent Publication No. Hei 9-133205, in a shift downshift, the transmission torque capacity of the friction engagement element on the high speed side is reduced by the output shaft torque within the first time of the initial stage of the shift. , The transmission torque capacity of the high-speed friction engagement element is increased to the same level as the input shaft torque within the second time thereafter, and the transmission torque of the low-speed friction engagement element is reduced. Appropriately controlling the capacity, after the lapse of the second time,
The transmission torque capacity of the low-speed side frictional engagement element is increased to the input shaft torque or more, and the high-speed side frictional engagement element is released.

[0005]

By the way, in order to perform a shift by changing the frictional engagement element without causing a torque loss or a large rotational upsurge,
It is desired to perform release control of the release-side friction engagement element by hydraulic control based on the hydraulic pressure corresponding to the critical state.

Here, the critical state can be determined based on, for example, the input shaft rotation speed of the transmission mechanism.
There is a delay in the detection of the input shaft rotation speed, and if the responsiveness of the criticality determination based on the input shaft rotation speed is high, the critical state is erroneously determined based on rotation fluctuations and detection errors unrelated to the shift operation. Responsiveness cannot be increased so much, and as a result, the criticality determination is delayed with respect to the actual critical state. Then, if the criticality determination is delayed, an error occurs in the hydraulic pressure set as the one corresponding to the critical state, and the accuracy of the subsequent release control deteriorates, and problems such as an increase in rotational speed increase occur. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can accurately detect a hydraulic pressure corresponding to a critical state even if a delay occurs in the criticality determination. It is an object of the present invention to provide a shift control device capable of performing the shift operation with high accuracy.

[0008]

SUMMARY OF THE INVENTION Therefore, an invention according to a first aspect of the present invention is directed to an automatic transmission configured to shift by changing a friction engagement element that simultaneously performs engagement control and release control of different friction engagement elements. In the shift control device, the critical state of the disengagement side frictional engagement element is determined while gradually decreasing the command pressure of the disengagement side frictional engagement element based on the shift determination, and a predetermined state is determined from the time when the critical state is determined. The command pressure before the time is detected as the command pressure corresponding to the critical state, and the release control of the release-side friction engagement element is performed based on the command pressure corresponding to the critical state.

[0009] With this configuration, in consideration of the delay in the criticality determination, a point in time that is a predetermined time before the point in time when the criticality is determined is regarded as a true critical state, and the command pressure before the predetermined time is determined. Is detected as an instruction pressure corresponding to the critical state.

According to the second aspect of the present invention, a reference input shaft rotation speed calculated based on the output shaft rotation speed of the transmission mechanism and the gear ratio before shifting is set, and the reference input shaft rotation speed and the actual input shaft rotation speed are set. And the input shaft rotation speed is compared to determine the critical state.

According to this configuration, the reference input shaft rotation speed obtained based on the output shaft rotation speed of the transmission mechanism and the gear ratio before the gear shift is determined when the release-side friction engagement element maintains the engaged state. The input shaft rotation speed (turbine rotation) is equal to the actual input shaft rotation speed if the disengagement side frictional engagement element is in the engaged state, but the disengagement side frictional engagement element becomes critical. When the slip occurs, the load applied to the engine is reduced, and idle rotation of the engine occurs. This is detected as an increase in the actual input shaft rotation speed with respect to the reference value.

According to the third aspect of the present invention, the critical state is determined when the actual input shaft rotation speed becomes higher than the reference input shaft rotation speed by a predetermined value or more. According to this configuration, even when the actual input shaft rotation speed becomes higher than the reference input shaft rotation speed, the critical state of the disengagement-side friction engagement element is not immediately determined, but the critical state is not increased until the input frictional rotation speed becomes larger than a predetermined value. Is determined.

[0013] In the invention described in claim 4, the indicated pressure is:
The calculation is performed based on the estimated value of the input shaft torque, the critical torque ratio, and the allowance, and the instruction pressure is gradually decreased by gradually decreasing the allowance.

According to such a configuration, an instruction pressure corresponding to the critical is obtained from the estimated value of the input shaft torque and the critical torque ratio,
By gradually reducing the margin to be added to the critical pressure, an instruction pressure is set from the fastening state toward the critical state.

According to a fifth aspect of the present invention, the margin is detected a predetermined time before the time when the critical state is determined as a parameter indicating an instruction pressure corresponding to the critical state.

According to such a configuration, as the result of gradually decreasing the margin to be added to the critical pressure-corresponding command pressure and reducing the command pressure, when the critical state of the disengagement side frictional engagement element is determined,
Detecting a margin allowance before a predetermined time, an instruction pressure obtained by adding a margin allowance a predetermined time before the criticality judgment to an instruction pressure corresponding to the criticality, an instruction pressure for bringing the disengagement side frictional engagement element into a critical state, I do. Here, if there is no error in the critical equivalent command pressure, the margin should be critical when the margin is zero, but the margin does not always become critical when the margin is zero due to an estimation error of the input shaft torque, etc. By detecting a margin corresponding to the criticality from the result of the criticality determination, it is possible to set the command pressure corresponding to the critical state even if there is an estimation error of the input shaft torque.

According to a sixth aspect of the present invention, the predetermined time is variably set based on at least one of a type of shift and a type of friction engagement element. According to this configuration, the delay time of the criticality determination is changed by the type of shift (second speed → 3rd speed).
A different value is set on the basis of at least one of the shift pattern (speed shift, third speed → fourth speed, etc.) and the type of friction engagement element (clutch / brake, etc.).

According to the present invention, the predetermined time is variably set in accordance with an operating state of an engine combined with the automatic transmission. According to such a configuration, the delay time of the criticality determination is set based on the load and the rotation speed of the engine combined with the automatic transmission.

[0019]

According to the first aspect of the present invention, even if the criticality judgment is delayed with respect to the actual criticality, the command pressure corresponding to the critical state can be accurately detected, and the disengagement side frictional engagement element can be detected. Has the effect of improving the accuracy of the release control of the vehicle and improving the shift controllability by changing gears.

According to the second aspect of the present invention, the occurrence of slippage in the disengagement side frictional engagement element is detected based on the occurrence of engine idling, so that the critical state of the release side frictional engagement element is determined. There is an effect that determination can be made with high accuracy.

According to the third aspect of the present invention, it is possible to prevent the erroneous determination of the critical state of the disengagement-side friction engagement element based on the fluctuation of the engine speed. According to the fourth aspect of the present invention, the instruction pressure can be reliably reduced and changed from the fastening state toward the critical state with reference to the instruction pressure corresponding to the critical state, and the timing of the critical state is predicted in advance. Therefore, there is an effect that the state can be shifted to the critical state within a substantially required time.

According to the fifth aspect of the present invention, by obtaining a margin corresponding to the critical state, the critical equivalent instruction pressure calculated from the estimated value of the input shaft torque and the critical torque ratio is converted to the true critical equivalent value. There is an effect that the correction can be made.

According to the sixth aspect of the invention, there is an effect that the command pressure in the critical state can be accurately detected in accordance with the difference in the criticality judgment delay time depending on the type of shift and / or the type of frictional engagement element. .

According to the seventh aspect of the invention, there is an effect that the command pressure in the critical state can be accurately detected in response to the difference in the criticality judgment delay time due to the engine load, the rotation speed, and the like.

[0025]

Embodiments of the present invention will be described below. FIG. 1 shows a transmission mechanism of an automatic transmission according to an embodiment, in which an output of an engine is transmitted to a transmission mechanism 2 via a torque converter 1.

The transmission mechanism 2 includes two sets of planetary gears G1,
G2, 3 sets of multiple disc clutches H / C, R / C, L / C, 1
A set of brake bands 2 & 4 / B, a set of multiple disc brakes L & R / B, and a set of one-way clutch L / OWC.

The two sets of planetary gears G1 and G2 are simple planetary gears including sun gears S1 and S2, ring gears r1 and r2, and carriers c1 and c2, respectively. The sun gear S1 of the planetary gear set G1 has a reverse clutch R /
C is configured to be connectable to the input shaft IN, and is configured to be fixable by the brake bands 2 & 4 / B.

The sun gear S2 of the planetary gear set G2 is directly connected to the input shaft IN. The carrier c1 of the planetary gear set G1 is configured to be connectable to the input shaft I by a high clutch H / C, while the ring gear r of the planetary gear set G2 is connected.
2 is configured to be connectable to the carrier c1 of the planetary gear set G1 by a low clutch L / C, and is further configured to be coupled to the carrier c of the planetary gear set G1 by a low & reverse brake L & R / B.
1 can be fixed.

The ring gear r1 of the planetary gear set G1 and the carrier c2 of the planetary gear set G2 are directly and integrally connected to the output shaft OUT. In the transmission mechanism 2 having the above-described configuration, the first to fourth speeds and the reverse are realized by a combination of engagement states of the clutches and brakes, as shown in FIG.

In FIG. 2, a circle indicates a fastened state, and a part without a symbol indicates a released state. In particular, the low & reverse brake L at the first speed is used.
The fastening state indicated by a black circle of & R / B indicates fastening only in one range.

According to the combination of the engaged states of the clutches and brakes shown in FIG. 2, for example, during a downshift from the fourth speed to the third speed, the brake bands 2 & 4 / B are released and the low clutch L / C is engaged. During the downshift from the third speed to the second speed, the high clutch H / C is released and the brake bands 2 & 4 / B are engaged. At the time of the upshift from the second speed to the third speed,
The brake bands 2 & 4 / B are released and the high clutch H / C is engaged. At the time of the upshift from the third speed to the fourth speed, the low clutch L / C is released and the brake bands 2 & 4 / B are engaged. That is, as described above, the shift in which the engagement and disengagement of the clutch / brake (friction engagement element) is simultaneously controlled to change the friction engagement element is referred to as a shift shift.

Each of the clutches and brakes (friction engagement elements) is operated by a supply hydraulic pressure.
The supply hydraulic pressure for each clutch / brake is adjusted by various solenoid valves included in the solenoid valve unit 11 shown in FIG.

An A / T controller 12 for controlling various solenoid valves of the solenoid valve unit 11 includes an A / T oil temperature sensor 13, an accelerator opening sensor 14,
Detection signals from the vehicle speed sensor 15, the turbine rotation sensor 16, the engine rotation sensor 17, the air flow meter 18, and the like are input, and the engagement hydraulic pressure in each friction engagement element is controlled based on the detection results.

In FIG. 3, reference numeral 20 indicates an engine combined with the automatic transmission. Here, the state of the shift change by the A / T controller 12 will be described.
As an example of an upshift (hereinafter, referred to as a power-on upshift) in a state in which the driving torque of the engine is being applied, FIGS.
This will be described with reference to the flowchart of FIG.

The flowchart of FIG. 5 shows a main control routine common to the engagement-side friction engagement element and the release-side friction engagement element. In step S1, a shift determination of a power-on upshift is performed.

The A / T controller 12 has a vehicle speed VSP
A shift map in which the shift speed is set according to the accelerator opening (throttle opening) is stored in advance. For example, the current shift speed (before shifting) and the shift speed searched from the shift map are different. If it is in the upshift direction and the accelerator is not fully closed, it is determined as a power-on upshift.

When the power-on upshift shift is determined, the process proceeds to step S2, in which the output shaft rotation speed No of the transmission mechanism is multiplied by the gear ratio before shifting (number of teeth of driven gear / number of teeth of driving gear). It is determined whether or not the input shaft rotation speed (turbine rotation speed) Nt of the transmission mechanism is higher than the sum of the reference turbine rotation obtained as a result and the hysteresis value HYS stored in advance.

If the turbine rotation speed Nt is equal to or less than the sum of the reference turbine rotation and the hysteresis value HYS, it is determined that the release-side friction engagement element has not been released, and the preparation phase process in step S3 is performed. Let it run.

The preparation phase process in step S3 is as follows.
The release-side preparation phase process is divided into the release-side process and the engagement-side process, and is shown in the flowcharts of FIGS.

The flowchart of FIG. 6 shows the main routine of the preparation phase processing of the disengagement side frictional engagement element. In step S31, the main routine is stored in advance according to the type of shift and the type of frictional engagement element to be disengaged. It is determined whether or not a predetermined time TIMER1 has elapsed from the shift determination.

If the time is within the predetermined time TIMER1, the process proceeds to step S32 to calculate the release initial hydraulic pressure. The release initial hydraulic pressure is an initial pressure for performing release control, and is a predetermined time TI from the hydraulic pressure during non-shift to the release initial hydraulic pressure.
It should be lowered in MER1.

The calculation of the initial disengagement hydraulic pressure in step S32 is shown in detail in the flowchart of FIG. 7. In step S321, the non-shift-time hydraulic pressure Po0 (instruction pressure) of the frictional engagement element for which the present release control is performed, An initial release hydraulic pressure Po1 (instruction pressure) of the friction engagement element is calculated.

The non-shift hydraulic pressure Po0 is calculated as Po0 = K1 × (Tt × Tr−o × room allowance (0)) + Prtn−o.

Here, K1 is a coefficient for converting the transmission torque capacity (required transmission torque capacity) of the disengagement-side friction engagement element into a hydraulic pressure, and indicates the type of shift and the type of friction engagement element to be disengaged. Is stored in advance in accordance with. Also, T
t is an estimated value of the input shaft torque of the transmission mechanism, and is estimated from, for example, the output torque of the engine estimated from the intake air amount, the engine rotation speed, and the like, and the torque ratio of the torque converter. Tr-o is a release critical torque ratio for obtaining a critical transmission torque capacity at which the release-side friction engagement element causes slippage with respect to the input shaft torque Tt. Room
(0) is a correction value for adding a marginal torque capacity to the critical transmission torque capacity, and is stored in advance, for example, as a value of about 3.0. Prtn-o is the release-side standby pressure (release-side return spring pressure) and is stored in advance for each friction engagement element.

On the other hand, the release initial oil pressure Po1 is calculated as Po1 = K1 × (Tt × Tr−o × room allowance (1)) + Prtn−o.

That is, only the margin is different from the arithmetic expression of the non-shifting-time hydraulic pressure Po0. In the arithmetic expression of the release initial hydraulic pressure Po1, the allowance (1) is set to a relatively low value of about 1.2. .

Note that the allowance (1) (= about 1.2) does not occur even if the estimation error of the input shaft torque occurs within the expected range.
The release-side friction engagement element is set as a value that can maintain the engaged state.

At the time of non-shifting, the hydraulic pressure is controlled to the non-shifting hydraulic pressure Po0, but when releasing in response to a shift request, the hydraulic pressure is reduced from the non-shifting hydraulic pressure Po0 to the release initial hydraulic pressure Po1 within the predetermined time TIMER1. In step S322, the hydraulic pressure decreasing gradient Rmp-Po1 within the predetermined time TIMER1 is calculated as Rmp-Po1 = (Po0-Po1) / TIMER1.

Then, the hydraulic pressure is reduced by (Rmp-Po1) every unit time from the non-shifting hydraulic pressure Po0, and is reduced to the release initial hydraulic pressure Po1 when a predetermined time TIMER1 has elapsed.

After the pressure is reduced to the release initial oil pressure Po1 within the predetermined time TIMER1 as described above, the process proceeds to step S3.
In step 3, until the turbine rotation speed Nt is determined to be higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS, the sharing ratio ramp control in step S34 is executed. I do.

Details of the sharing ratio ramp control in step S34 are shown in the flowchart of FIG. 8. In step S341, the release initial oil pressure Po1 is calculated, and the release oil pressure Po2 is calculated.

The release hydraulic pressure Po2 (instruction pressure) is calculated as Po2 = K1 × (Tt × Tr−o × room allowance (2)) + Prtn-o, and 1.0 is used as the allowance allowance (2).
Use a smaller value, for example, about 0.8 (Margin (0)>
Extra room (1)>0> extra room (2)).

The margin (2) (approximately 0.8) can be obtained even if the estimation error of the input shaft torque occurs within the expected range.
The value is set as a value that can surely cause the release-side friction engagement element to shift to the release state. Therefore, the release initial hydraulic pressure P
The decrease in oil pressure from o1 to the release oil pressure Po2 is performed to surely shift the release-side friction engagement element to the release state (see FIG. 27).

In step S342, the release initial oil pressure Po is set within a predetermined time TIMER2 stored in advance according to the type of shift and the type of friction engagement element to be released.
The oil pressure ramp gradient (the oil pressure decrease width per unit time) for decreasing from 1 to the release oil pressure Po2 is calculated as Rmp-Po2 = (Po1-Po2) / TIMER2.

Then, it is determined that the turbine rotation speed Nt is equal to or less than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS within the predetermined time TIMER2 from the time when the predetermined time TIMER1 has elapsed. In this state, the hydraulic pressure is reduced by (Rmp-Po2) every unit time.

The ramp gradient Rmp-Po2 is set to be smaller than the gradient Rmp-Po1 by setting the variation width of the margin and the predetermined time TIMER2 so that the margin is 1.0.
The change in the transmission torque capacity of the disengagement side frictional engagement element is set to be slower than before in a predetermined range before and after the following.

When the engagement oil pressure is gradually reduced by the gradient Rmp-Po2, the reference turbine speed (No × gear ratio) and the hysteresis value HY are reached when the allowance becomes close to 1.0.
By detecting the idling state of the engine whose turbine rotation speed Nt is higher than the value added to S, it is possible to indirectly know that the transmission torque capacity on the release side has decreased to near the criticality.

As described above, when the margin becomes close to 1.0, it is ideal that the turbine rotation speed Nt becomes higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. However, if there is an estimation error in the input shaft torque Tt, the engine will run idle after the margin has become larger than 1.0 or becomes smaller than 1.0, and the estimation error of the input shaft torque Tt is anticipated. The change range of the margin within the predetermined time TIMER2 is 1.
It is necessary to secure a wide area centered on 0.

Here, for example, if the gear ratio starts to change at the release hydraulic pressure corresponding to the margin allowance = 1.1, the input torque is estimated to be smaller than the actual value. As a result, it is determined that the vehicle has started to slip despite the hydraulic pressure capable of maintaining the engaged state, and conversely, if the gear ratio starts to change at the release-side hydraulic pressure corresponding to, for example, a margin allowance of 0.9, the input shaft torque is estimated. Since the estimated value is larger than the actual value, it is determined that the start of slippage is delayed although the hydraulic pressure (transmission torque capacity) that cannot maintain the original engaged state has already been reduced.

Therefore, the estimated input shaft torque value is corrected based on the allowance at the time when the turbine rotation speed Nt first becomes higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. The correction coefficient for the correction coefficient is obtained, and the correction by the correction coefficient is learned.

That is, step S in the flowchart of FIG.
If it is determined in step 33 that the turbine rotation speed Nt is higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS, the process proceeds to step S35, where learning correction control of the input shaft torque is performed.

The state of the learning correction control of the input shaft torque is shown in the flowchart of FIG.
At 51, the turbine rotation speed Nt is smaller than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS.
Ask for a margin when the price rises for the first time. Specifically, the engagement hydraulic pressure of the disengagement-side friction engagement element when the turbine rotation speed Nt first becomes higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS, and the input at that time The margin Tr is calculated back from the shaft torque.

In step S352, as shown in FIG. 29, a table in which the correction coefficient Ktt of the input shaft torque is stored in advance in accordance with the difference (1-Tr) between 1.0 and the allowance Tr when the engine is idling is generated. Step S
The correction coefficient Ktt is determined by referring to the table based on the allowance Tr determined in 351.

The correction coefficient Ktt is such that the allowance Tr is 1.
When the margin Tr is smaller than 1.0, the value is set to 1.0. When the margin Tr is larger than 1.0, the value is set to a value larger than 1.0.
so that when r is 1.0, the engine blows,
Correct the estimated value of the input shaft torque.

When the correction coefficient Ktt is set, learning is performed so as to estimate the input shaft torque including a correction request based on the correction coefficient Ktt. In step S36 of the flowchart in FIG. 6, the sharing ratio ramp learning is performed.

The sharing ratio ramp learning is shown in detail in the flowchart of FIG. In step S361,
It is determined whether or not the torque estimation learning has been completed. Specifically, when the correction coefficient Ktt set based on the allowance Tr at the time of occurrence of engine idling converges to a narrow range including 1.0 (for example, 0.95 ≦ Ktt ≦ 1.05), the end of the torque estimation learning is determined. judge.

When the end of the torque estimation learning is determined, the process proceeds to step S362, in which the margins (1) and (2) used for calculating the release initial hydraulic pressure Po1 and the release hydraulic pressure Po2 are changed from the initial values. I do.

The above change is a change to make the allowance (1) smaller, and a correction to make the allowance (2) larger, and the change width from the allowance (1) to the allowance (2). (See FIG. 28). For example,
When the initial value of (1) is 1.2 and the initial value of the allowance (2) is 0.8, the allowance (1) is changed to 1.1 and the allowance (2) is changed to 0.8.

When the allowances (1) and (2) are changed as described above, the margin of change in the allowance at the predetermined time TIMER1 immediately after the shift determination is increased, and the decrease gradient of the release hydraulic pressure is increased. The change width of the margin in TIMER2 becomes smaller, and the gradient of the release hydraulic pressure decreases.

Here, the torque estimation learning has converged, and
Since the accuracy of estimating the input shaft torque is high, even if the margin of change in the predetermined time TIMER2 in which the decrease gradient of the release hydraulic pressure is made small becomes small, the predetermined time TIMER
The engine can be reliably shifted to the idling state within the engine 2.

Further, if the gradient of the release hydraulic pressure at the time of shifting to the engine idling state is made gentler, the hydraulic pressure corresponding to the critical state can be accurately determined, and the controllability of the hydraulic pressure in the subsequent torque phase is improved. Thus, the rotation change at the beginning of the torque phase can be moderated.

On the other hand, the preparation phase process on the fastening side is as shown in FIG.
1 is shown in the flowchart. The flowchart of FIG. 11 shows the preparation phase process on the engagement side. In step S41, it is determined whether or not the turbine rotation speed Nt is higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. Is determined.

When it is determined that the turbine rotation speed Nt is equal to or less than the sum of the reference turbine rotation (No.times.gear ratio) and the hysteresis value HYS, in other words, engine idling occurs. Until the time, the process proceeds to step S42.

In step S42, the reference precharge pressure of the engagement-side friction engagement element is set according to the type of the friction engagement element. In the next step S43, the reference precharge pressure is processed by a transient hydraulic pressure compensation filter having a gain corresponding to the oil temperature to determine the final hydraulic pressure of the engagement side frictional engagement element.

The transient hydraulic pressure compensation filter is a filter for improving the transient response when changing the actual hydraulic pressure to the reference precharge pressure, which is the target hydraulic pressure. It is set so as to make a large step change, and then to make the indicated oil pressure secondary vibrate to converge to the original target. Further, the filter gain is set to an oil corresponding to the transient response of the oil pressure change depending on the oil temperature. It changes according to the temperature.

Thus, when the power-on upshift is determined, the hydraulic pressure of the engagement-side frictional engagement element increases responsively to the reference precharge pressure, and then changes to the reference precharge pressure until engine idling is detected. Held at pressure.

Here, returning to the flowchart of FIG. 5, the explanation will be continued. In step S2, the turbine rotation speed Nt becomes higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. Is determined, it is determined whether the gear ratio has exceeded the F / B start gear ratio and has changed in the upshift direction. Then, after it is determined that the engine is blowing, F /
Until the gear ratio exceeds the B start gear ratio and changes in the upshift direction, the torque phase process of step S5 is performed.

As will be described later, when the gear ratio changes beyond the F / B start gear ratio, feedback control of turbine rotation is performed. Note that F / B is an abbreviation for feedback.

The flowchart of FIG. 12 shows the state of the torque phase process of the disengagement side frictional engagement element.
In step S51, it is determined whether or not the time derivative of the deviation between the turbine rotation speed Nt and the reference turbine rotation (No × gear ratio) is negative.

Then, d / dt (Nt−No × gear ratio)
While ≧ 0, that is, while the deviation between the turbine rotation speed Nt and the reference turbine rotation (No × gear ratio) is increasing and changing, the process proceeds to step S52, and the torque sharing ratio holding control is performed.

FIG. 13 shows the torque sharing ratio holding control in detail. In the flowchart of FIG. 13, in step S521, a predetermined time TI from when the turbine rotation speed Nt first becomes higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS.
The surplus generation Trbefore at the time before M1 is obtained.

The turbine rotation speed N is calculated from the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS.
The point in time when t becomes high for the first time is determined as a critical state of the disengagement side frictional engagement element. Since HYS is added to the reference turbine speed, a delay occurs in the criticality determination based on the turbine rotation speed Nt with respect to the true criticality.

Therefore, the point in time that is delayed by the delay time from the point in time when the criticality is determined is estimated to be a true critical state, and the margin at that time is detected as a critical equivalent value. Is set in accordance with the delay time.

Therefore, by adding the allowance Trbefore at the point in time before the predetermined time TIM1 to the estimated critical equivalent pressure obtained from the estimated value of the input shaft torque and the critical torque ratio, the input shaft torque at that time is added. The true critical equivalent pressure can be determined.

Since the delay time of the criticality judgment differs depending on the type of shift and friction engagement element, the predetermined time TIM1 is set to the type of shift (second speed → third speed, third speed → fourth speed, etc.).
And / or the type of friction engagement element (brake band 2 & 4
/ B, low clutch L / C, etc.).

Further, since the difference in the delay time of the criticality judgment can be estimated based on the engine load and the rotation speed indicating the engine operation state, the predetermined time TIM1 is changed according to the engine load and / or the engine rotation speed. You can also.

In the next step S522, the margin T
Based on rbefore, d / dt (Nt-No x gear ratio)
The hydraulic pressure Po3 on the release side while ≧ 0 is calculated. Po3 = K1 × (Tt × Tr-o × Tolerance Trbefore) + P
rtn-o d / dt (Nt-No)
(× gear ratio) ≧ 0, the disengagement-side friction engagement element is accurately maintained in the critical state.

On the other hand, if it is determined in step S51 of the flowchart of FIG. 12 that d / dt (Nt-No.times.gear ratio) <0, the flow proceeds to step S53 to perform release torque correction control.

The release torque correction control is shown in detail in FIG. In step S531, d / dt (Nt
−No × gear ratio) according to the magnitude of the release correction torque Th.
osei-o is calculated with reference to a table as shown in FIG.

The release correction torque Thosei-o is d / dt
When (Nt−No × gear ratio) is 0 or more, 0 and d
When / dt (Nt−No × gear ratio) is negative, the absolute value is set to a larger negative value as the absolute value increases.

At the next step S532, the input shaft torque Tt is corrected using the release correction torque Thosei-o to calculate the release hydraulic pressure Po4. Po4 = K1 x [(Tt + Thosei-o) x Tr-o x margin T
rbefore] + Prtn-o According to the calculation of the release hydraulic pressure Po4, the release correction torque Tho
By repeating the input shaft torque reduction correction by sei-o, the release hydraulic pressure is gradually reduced in accordance with the convergence of the engine running.

Then, when the gear ratio exceeds the F / B start gear ratio and changes in the upshift direction, the step is changed from the released hydraulic pressure at that time to the hydraulic pressure = 0. On the other hand, the torque phase process on the engagement side is performed as shown in the flowchart of FIG.

In step S61, it is determined whether or not the turbine rotation speed Nt is higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. If the turbine rotation speed Nt is higher, the process proceeds to step S62. move on.

In step S62, it is determined whether or not a predetermined time TIMER3 has elapsed since the turbine rotation speed Nt first became higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS. The predetermined time TIMER3 is set according to the type of the speed change and the friction engagement element.

When it is determined that the time is within the predetermined time TIMER3, the process proceeds to step S63, and the preparation hydraulic control on the engagement side is performed. The state of the preparation hydraulic control is shown in FIG.
Is shown in the flowchart of FIG.

In step S631, the engagement side frictional engagement element does not transmit engine torque (engagement torque sharing ratio = 0), and rises to a hydraulic pressure of about 0.8 times the engagement critical torque ratio Tr-c for a predetermined time TIMER3. In step S632, the command oil pressure Pc1 on the engagement side is set.
Pc1 = K2 × Tt × Tr-c × (0.8 × Rmp-Tr1)
Calculated as + Prtn-c.

Here, K2 is a coefficient for converting the transmission torque capacity (required transmission torque capacity) of the engagement-side friction engagement element into a hydraulic pressure. Is stored in advance in accordance with. Tr-c
Is a critical engagement torque ratio for determining a critical transmission torque capacity at which the frictional engagement element on the engagement side starts engaging with respect to the input shaft torque Tt. Prtn-c is a standby pressure on the engagement side (return spring pressure on the engagement side) and is stored in advance for each friction engagement element.

Further, as shown in FIG. 31, Rmp-Tr1 is a coefficient that increases at a constant speed from 0 to 1 within a predetermined time TIMER3, and is determined from the standby pressure (reference precharge pressure) on the engagement side to the engagement critical level. Increase and change the hydraulic pressure on the fastening side to 0.8 times the torque (margin = 0.8). The predetermined time TIMER3 is set according to the type of the speed change and the friction engagement element.

Step S62 in the flowchart of FIG.
If it is determined that the predetermined time TIMER3 has elapsed since the turbine rotation speed Nt first became higher than the sum of the reference turbine rotation (No × gear ratio) and the hysteresis value HYS, the process proceeds to step S64.

In step S64, it is determined whether or not the gear ratio has become smaller than the F / B start gear ratio.
If it is larger than the / B start gear ratio, step S65
Proceed to and perform the sharing ratio ramp control.

The sharing ratio ramp control is shown in the flowchart of FIG. First, in step S651, the initial allowance (1) = 0.8 from the initial allowance (1) = 0.8 in the predetermined time TIMER4.
(2) It is changed at a constant speed until 1.2 (see FIG. 32), and a setting is made to increase the command pressure on the engagement side as the margin increases. The predetermined time TIMER4 is set according to the type of the speed change and the friction engagement element.

In step S652, an initial pressure Pc2 and a final pressure Pc3 corresponding to the increase in the margin are calculated, and the command pressures Pc2 and Pc3 are calculated with the predetermined time TIMER.
4 to calculate the ramp gradient Rmp-Pc3 of the indicated pressure.

Pc2 = K2 × Tt × Tr-c × Margin (1) + Prtn-c Pc3 = K2 × Tt × Tr-c × Margin (2) + Prtn-c Rmp-Pc3 = (Pc3-Pc2) / TIMER4 In step S653, control is performed to gradually increase the engagement-side command oil pressure Pc4 according to the ramp gradient Rmp-Pc3.

After the sharing ratio ramp control, the idling correction control in step S66 is performed. The above-described idling correction control will be described with reference to the flowchart of FIG. 18. In step S661, a correction torque Thosei-c is obtained according to d / dt (Nt−No × gear ratio).

As shown in FIG. 33, the correction torque Thosei-c is 0 when d / dt (Nt−No × gear ratio) is negative, but d / d when it is positive.
The larger the value of t (Nt−No × gear ratio), the larger the positive value.

In step S662, the command oil pressure Pc4 controlled to increase at a constant speed is increased by the correction torque Tho.
The command pressure Pc5 is calculated by correcting with sei-c. Pc5 = Pc4 + K2.times.Tr-c.times.Thosei-c Further, in step S67, transient hydraulic pressure compensation similar to that in step S43 is performed.

That is, as shown in the flowchart of FIG. 19, in step S671, the gain is set according to the oil temperature,
In the next step S672, the command pressure Pc5 is processed by the transient hydraulic pressure compensation filter having a gain corresponding to the oil temperature to determine the final hydraulic pressure Pc6 of the frictional engagement element on the engagement side.

In step S4 of the flowchart in FIG.
If it is determined that the gear ratio has become smaller than the F / B start gear ratio, the process proceeds to step S6, and it is determined whether the gear ratio has become smaller than the F / B end gear ratio (<F / B start gear ratio). Determine.

If the gear ratio has become smaller than the F / B start gear ratio but larger than the F / B end gear ratio, the inertia phase process of step S7 is performed. The release-side inertia phase process is shown in the flowchart of FIG. 20. In step S71, the hydraulic pressure at the end of the torque phase (oil pressure = 0) is held.

Further, the inertia phase process on the fastening side is shown in the flowchart of FIG. In the flowchart of FIG. 21, in step S81, the basic control shown in the flowchart of FIG. 22 is performed.

In the basic control, first, in step S811, the inertia torque Tinr is calculated. As shown in FIG. 34, the inertia torque Tinr (shift torque) is stored in advance as a table value corresponding to the target shift time, and is set to a larger value as the target shift time becomes shorter.

In step S812, the engagement-side command pressure Pc7 is calculated based on the inertia torque Tinr. Pc7 = K2 × Tt × Tr-c + Prtn-c + K2 × Tr-c ×
(Tinr × HOSEI-VSP) The command pressure Pc7 is a critical pressure corresponding to the input torque,
This is calculated as a value obtained by adding the hydraulic pressure corresponding to the inertia torque Tinr. Further, the inertia torque Tinr is further corrected to increase as the vehicle speed becomes higher by using a correction coefficient HOSEI-VSP corresponding to the vehicle speed VSP (see FIG. 35).

In step S82, in addition to the above basic control, rotation feedback (F / B) control is executed. The rotation F / B control will be described with reference to the flowchart of FIG.

In step S821, a target turbine rotation is calculated. The target turbine rotation is changed from the gear ratio before the gear shift in the target gear shift time to the gear ratio after the gear shift at a constant speed in the target gear shift time and the target gear ratio every moment (FIG. 36).
), And the output shaft rotation No.

In step S822, the feedback correction PID is proportionally / integrally / differentially controlled so that the actual turbine rotation matches the target turbine rotation. In the next step S823, the feedback correction PI
In D, the instruction pressure Pc7 in the basic control is corrected, and the engagement-side instruction pressure Pc8 is set.

If it is determined in step S6 of the flowchart of FIG. 5 that the gear ratio has become smaller than the F / B end gear ratio, the process proceeds from step S6 to step S8, where the gear ratio is changed to the F / B end gear ratio. Then, it is determined whether or not a predetermined time TIMER7 has elapsed from the first time the value has become smaller.

If the time is within the predetermined time TIMER7, the flow advances to step S9 to perform an end phase process.
The end phase process for the disengagement side frictional engagement element is shown in the flowchart of FIG. 24. In step S91, a setting is made to hold the oil pressure at the end of the inertia phase. That is, the hydraulic pressure of the disengagement-side friction engagement element is determined by the gear ratio of F /
It will be kept at 0 from the point in time when it becomes smaller than the B start gear ratio.

On the other hand, the termination phase processing of the engagement side frictional engagement element is shown in the flowchart of FIG.
At 101, it is determined whether or not within a predetermined time TIMER7 from the time when the gear ratio first becomes smaller than the F / B end gear ratio. Execute.

Details of the end phase process in step S101 are shown in the flowchart of FIG. 26. In step S111, the predetermined time from the hydraulic pressure corresponding to the critical engagement torque to the hydraulic pressure corresponding to 1.2 times the critical engagement torque is determined. The setting to raise in TIMER7 is performed. The predetermined time TIMER7 is set according to the type of the speed change and the friction engagement element.

In step S112, the engagement side instruction pressure Pc
9 as Pc9 = K2 × Tt × Tr-c × (1 + 0.2 × Rmp-Tr2) + P
rtn-c + K2 × Tr-c × (Tinr × HOSEI-VSP) Here, Rmp-Tr2 is, as shown in FIG.
It is a coefficient that changes at a constant speed from 0 to 1.0 in IMER7. When the coefficient Rmp-Tr2 is 0, Pc9 = Pc8, and the oil pressure in the inertia phase is set as an initial value and Pc
9 = K2 × Tt × Tr-c × 1.2 + Prtn-c + K2 × Tr-c ×
Until (Tinr × HOSEI-VSP), the hydraulic pressure is increased within a predetermined time TIMER7.

At the time when the predetermined time TIMER7 has elapsed, the command pressure on the fastening side is changed to Pc9 = K2 × T
t × Tr-c × 1.2 + Prtn-c + K2 × Tr-c × (Tinr × HOSE
Step change from I-VSP) to the maximum pressure.

Although the above embodiment relates to an upshift, the change of the decreasing speed of the release-side command pressure based on the learning of the estimation error of the input shaft torque is controlled by the release control of the friction engagement element in the downshift. Can also be applied.

It is clear that the transmission mechanism is not limited to the one shown in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transmission mechanism of an automatic transmission according to an embodiment.

FIG. 2 is a diagram showing a correlation between a combination of engagement states of frictional engagement elements in the transmission mechanism and a shift speed.

FIG. 3 is a system diagram showing a control system of the automatic transmission.

FIG. 4 is a time chart showing a state of shifting by changing the friction engagement element in the embodiment.

FIG. 5 is a flowchart showing a state of a shift change control of a friction engagement element in the embodiment.

FIG. 6 is a flowchart illustrating a preparation phase process of a disengagement-side friction engagement element.

FIG. 7 is a flowchart showing a disengagement initial hydraulic pressure calculation in a disengagement-side friction engagement element preparation phase process.

FIG. 8 is a flowchart illustrating a sharing ratio ramp control in a preparation phase process of a release-side friction engagement element.

FIG. 9 is a flowchart illustrating input shaft torque learning in a preparation phase process of a disengagement-side friction engagement element.

FIG. 10 is a flowchart illustrating a sharing ratio ramp learning in a preparation phase process of a release-side friction engagement element.

FIG. 11 is a flowchart illustrating a preparation phase process of a fastening-side friction engagement element.

FIG. 12 is a flowchart showing a torque phase process of a disengagement-side friction engagement element.

FIG. 13 is a flowchart showing a torque sharing ratio holding control in a torque phase process of a disengagement side frictional engagement element.

FIG. 14 is a flowchart showing release torque correction control in a torque phase process of a release-side friction engagement element.

FIG. 15 is a flowchart showing a torque phase process of the engagement-side friction engagement element.

FIG. 16 is a flowchart showing a preparation hydraulic control in a torque phase process of the engagement-side friction engagement element.

FIG. 17 is a flowchart illustrating a sharing ratio ramp control in a torque phase process of the engagement-side friction engagement element.

FIG. 18 is a flowchart showing idling correction control in a torque phase process of the engagement-side friction engagement element.

FIG. 19 is a flowchart showing transient hydraulic pressure correction in a torque phase process of the engagement-side friction engagement element.

FIG. 20 is a flowchart showing inertia phase processing of a disengagement-side friction engagement element.

FIG. 21 is a flowchart showing an inertia phase process of the engagement-side friction engagement element.

FIG. 22 is a flowchart showing basic control in an inertia phase process of the engagement-side friction engagement element.

FIG. 23 is a flowchart showing rotation F / B control in an inertia phase process of the engagement-side friction engagement element.

FIG. 24 is a flowchart showing a termination phase process of a disengagement-side friction engagement element.

FIG. 25 is a flowchart showing an end phase process of the engagement-side friction engagement element.

FIG. 26 is a flowchart showing details of a termination phase process of the engagement-side friction engagement element.

FIG. 27 is a diagram showing a change characteristic of a margin in a preparation phase process of a release-side friction engagement element.

FIG. 28 is a graph showing a change characteristic of a margin in a preparation phase process of a disengagement-side friction engagement element before and after learning of an estimation error.

FIG. 29 is a diagram showing a correlation between a margin when an idling occurs and a correction coefficient of an input shaft torque.

FIG. 30 is a diagram showing characteristics of an idling correction torque in a release-side friction engagement element.

FIG. 31 is a diagram showing a ramp characteristic of the hydraulic pressure in the preparation hydraulic control in the engagement-side friction engagement element.

FIG. 32 is a graph showing a change characteristic of a margin in the sharing ratio ramp control in the engagement-side friction engagement element.

FIG. 33 is a diagram showing characteristics of an idling correction torque in an engagement-side friction engagement element.

FIG. 34 is a diagram showing a correlation between a shift time and an inertia torque.

FIG. 35 is a diagram showing a correction coefficient according to a vehicle speed of an inertia torque.

FIG. 36 is a graph showing a correlation between a target shift time and a target gear ratio.

FIG. 37 is a diagram showing a ramp characteristic of hydraulic pressure in a termination phase on the engagement side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Torque converter 2 ... Transmission mechanism 11 ... Solenoid valve unit 12 ... A / T controller 13 ... A / T oil temperature sensor 14 ... Accelerator opening degree sensor 15 ... Vehicle speed sensor 16 ... Turbine rotation sensor 17 ... Engine rotation sensor 18 ... Air flow Meter 20 Engine G1, G2 Planetary gear H / C High clutch R / C Reverse clutch L / C Low clutch 2 & 4 / B 2nd / 4th speed band brake L & R / B Low and reverse brake

Claims (7)

[Claims] A shift control device for an automatic transmission configured to perform a shift by changing a friction engagement element that simultaneously performs engagement control and release control of different friction engagement elements, wherein the release side is determined based on a shift determination. While gradually decreasing the command pressure of the friction engagement element, the critical state of the release-side friction engagement element is determined, and the command pressure a predetermined time before the determination of the critical state is changed to the command pressure corresponding to the critical state. A shift control device for an automatic transmission, characterized in that the shift control is performed based on an instruction pressure corresponding to the critical state. 2. A reference input shaft rotation speed calculated based on an output shaft rotation speed of a transmission mechanism and a gear ratio before a shift is set, and the reference input shaft rotation speed and an actual input shaft rotation speed are calculated. 2. The shift control device for an automatic transmission according to claim 1, wherein the critical state is determined by comparing the critical states. 3. The automatic transmission according to claim 2, wherein the critical state is determined when an actual input shaft rotation speed is higher than a reference input shaft rotation speed by a predetermined value or more. Transmission control device. 4. A configuration in which the command pressure is calculated based on an estimated value of an input shaft torque, a critical torque ratio, and a margin.
4. The method according to claim 1, wherein the instruction pressure is gradually decreased by gradually decreasing the margin.
A shift control device for an automatic transmission according to any one of the preceding claims. 5. The system according to claim 4, wherein the margin is determined a predetermined time before the critical state is determined as a parameter indicating a command pressure corresponding to the critical state.
A shift control device for an automatic transmission according to claim 1. 6. The automatic apparatus according to claim 1, wherein the predetermined time is variably set based on at least one of a type of a shift and a type of a friction engagement element. Transmission control device for transmission. 7. The automatic transmission according to claim 1, wherein the predetermined time is variably set in accordance with an operation state of an engine combined with the automatic transmission. Transmission control device.