JP2010032028A - Shift controller of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift controller of an automatic transmission capable of synchronizing an engine revolution speed and an input revolution speed of the automatic transmission with each other without shifting the transition to a neutral state inside the automatic transmission at the time of shifting down. <P>SOLUTION: At the time t<SB>1</SB>when it is determined that the shifting down starts, a release side oil pressure P<SB>1</SB>is started to decrease. Afterward, during a period until a time point t<SB>p</SB>when an actual gear ratio i<SB>r</SB>reaches a given gear ratio i<SB>s</SB>, hydraulic pressure P<SB>1</SB>is held at a constant activation pressure Pa capable of obtaining a driving force Ft from the automatic transmission 4 without shifting the inside of the automatic transmission 4 to the neutral state. Then, after the time point t<SB>p</SB>, a release side hydraulic pressure P<SB>1</SB>is allowed to rise to a hydraulic pressure P<SB>b</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention performs an upshift or a downshift by increasing the hydraulic pressure of the engagement side friction element and decreasing the hydraulic pressure of the release side friction element. The present invention relates to a shift control device for an automatic transmission that increases the driving force of the engine and synchronizes the engine speed with the input rotation speed of the automatic transmission after downshifting.

When performing a downshift, a shift control device for an automatic transmission for so-called change-over shifts releases all friction elements that determine the shift stage before the downshift, and the automatic transmission is in a neutral state (power transmission is performed). The engine torque is feedback-controlled so that the engine speed is synchronized with the input speed of the automatic transmission after the downshift. After the engine speed is synchronized, the speed change after the downshift is performed. There exists a thing which completes the said downshift by fastening the friction element which determines a step | paragraph (for example, refer patent document 1).
JP 2006-112247 A

  According to such a shift control device, the shift shock can be reduced and the shift time can be shortened. There is a problem that will occur.

  That is, when the engine speed and the input speed of the automatic transmission are synchronized in the neutral state in the automatic transmission, the driving force output from the automatic transmission is lost, although it is temporary during downshifting. There is a problem in that the driving force is lost from the automatic transmission.

The problem to be solved by the present invention is that when the engine speed and the input speed of the automatic transmission are synchronized, the driving force from the automatic transmission is temporarily lost in accordance with the neutral state of the automatic transmission. To end up,
An object of the present invention is to provide a shift control device for an automatic transmission that can synchronize the engine speed and the input speed of the automatic transmission without bringing the automatic transmission into a neutral state during downshifting. It is to be.

The present invention has a plurality of friction elements that can be fastened and released by increasing or decreasing the hydraulic pressure, and increases the hydraulic pressure of the friction element to be fastened to tighten the friction element and reduce the hydraulic pressure of the friction element to be released. When the downshift is executed in the automatic transmission that performs upshift or downshift by releasing the friction element, the engine driving force is increased to reduce the engine speed after the downshift. In a shift control device for an automatic transmission that is synchronized with an input rotational speed,
Using the downshift start determination means, determine whether the downshift has started,
As a result of this determination, when it is determined that the downshift is started, the release side hydraulic control means is used to reduce the hydraulic pressure of the friction element to be released from the automatic transmission at least without the neutral state in the automatic transmission. Suppressing the driving force.

  As a method of suppressing the decrease in hydraulic pressure, it is preferable to maintain the hydraulic pressure at a constant shelf pressure in consideration of ease of control and stability. However, the automatic transmission is not in a neutral state. As long as it is a method that can maintain a state in which the driving force from the automatic transmission can be obtained, a method in which the slope of decrease in the oil pressure is made gentle, or conversely, the oil pressure is gradually raised may be used.

  According to the present invention, when it is determined that the downshift is started, the hydraulic pressure of the friction element to be released is started to be reduced, and thereafter, until the preset time is reached, the hydraulic pressure is reduced at least. Since the automatic transmission is restrained so that the driving force from the automatic transmission can be obtained without being in the neutral state, the internal speed of the automatic transmission is maintained even when the engine speed and the input rotational speed of the automatic transmission are synchronized. It will never be neutral.

  For this reason, according to the present invention, the driving force from the automatic transmission temporarily disappears even though the downshift is being performed, so that the driver does not feel idle. .

  Hereinafter, a shift control apparatus for an automatic transmission according to the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram schematically showing an outline of a shift control device for an automatic transmission according to one embodiment of the present invention.

  Reference numeral 1 denotes an engine having an electric throttle valve 3 in the intake passage 2. The driving force of the engine 1 increases in accordance with the opening degree of the electric throttle valve 3 as the opening degree increases. The opening degree of the electric throttle valve 3 is controlled by an engine control unit (hereinafter referred to as “ECU”) 101.

  Reference numeral 4 denotes an automatic transmission disposed on the output side of the engine 1. The automatic transmission 4 includes a lockup type torque converter (hereinafter referred to as “torque converter”) 4a directly connected to the output shaft of the engine 1, a stepped transmission 4b directly connected to the output shaft of the torque converter 4a, A hydraulic control unit 4c for hydraulically controlling engagement and disengagement of various friction elements represented by a clutch or a brake disposed in the stepped transmission 4b.

The stepped transmission 4b has a plurality of friction elements that can be engaged and released by increasing or decreasing the hydraulic pressure, and the hydraulic pressure of the friction element to be released (hereinafter referred to as “release-side friction element”) (hereinafter referred to as “release-side hydraulic pressure”). )) P ₁ is decreased to release the friction element, and the hydraulic pressure (hereinafter referred to as “fastening side hydraulic element”) P ₂ of the friction element to be fastened (hereinafter referred to as “fastening side friction element”) is increased. This is an automatic transmission for so-called change gear shifting that performs an upshift or a downshift by engaging the friction element.

  The hydraulic control unit 4c has a plurality of shift solenoids (not shown) corresponding to the various friction elements described above, and appropriately controls the shift solenoids by an automatic transmission control unit (hereinafter referred to as “ATCU”) 102. A suitable hydraulic pressure required for the shift control is realized.

Reference numeral S ₁ is an accelerator opening sensor that detects an accelerator opening APO corresponding to the amount of depression of the accelerator pedal and outputs the accelerator opening APO as a signal to the ECU 101 and the ATCU 102. Thereby, the driving force of the engine 1 can be controlled according to the depression amount of the accelerator pedal.

Reference numeral S ₂ is an engine rotation sensor that outputs a signal synchronized with the rotation of the crankshaft to the ECU 101. Rotational speed of the engine (hereinafter, referred to as "the engine speed") Ne can be detected based on a signal from an engine speed sensor S _2.

Reference numeral S ₃ denotes a transmission output shaft rotation sensor (hereinafter referred to as “output rotation sensor”) that outputs a signal synchronized with the rotation of the output shaft (hereinafter referred to as “transmission output shaft”) 5 of the automatic transmission 4 to the ATCU 102. ). Vehicle speed VSP may be detected based on the signal from the output rotation sensor S _2.

  The ECU 101 and the ATCU 102 are connected via the bidirectional communication line 6 so as to share each other's information.

  The ATCU 102 executes shift control according to the mode selected by the driver by operating the select lever 7. For example, in the automatic shift mode, whether or not a shift is necessary is determined according to the accelerator opening APO and the vehicle speed VSP, and the required shift is executed. In the manual shift mode, the driver's A target shift stage corresponding to the operation of the select lever is determined, and the required shift is executed.

  The ECU 101 controls the driving force from the engine 1 based on the accelerator opening APO, the engine speed Ne, and the shift request from the ATCU 102.

  For example, in a normal driving state in which no shift is performed, after calculating the driver's required torque based on the accelerator opening APO and the engine speed Ne, this required torque is set as the target engine torque Te (o). The electric throttle valve 3 is controlled according to the torque Te (o).

  On the other hand, when performing a shift, in particular, when performing a downshift, the target engine torque Te (o) is calculated while exchanging information with the ATCU 102, and electric control is performed according to the target engine torque Te (o). The throttle valve 3 is controlled.

  FIG. 2 is a flowchart schematically showing a main routine of the shift control according to the present invention executed by the ATCU 102. Note that this speed change control is repeatedly executed at preset time intervals.

  First, in step 1, it is determined whether or not a downshift is started by a change in the accelerator opening APO, a select lever operation, or the like. That is, step 1 corresponds to downshift start determining means. When the downshift start is not determined, the present control is temporarily terminated, whereas when the downshift start is determined, the process proceeds to step 2.

  In step 2, the driving force of the engine 1 is increased, and the engine speed Ne is downshifted in synchronization with the input speed of the automatic transmission 4 (in this embodiment, the input speed of the stepped transmission 4b). It is determined whether or not the synchronous shift control can be executed.

  If it is determined in step 2 that the rotation-synchronized shift control can be performed, the process proceeds to step 3 to execute the rotation-synchronized shift control. If it is determined that the rotation-synchronized shift control cannot be performed, the driving force of the engine 1 is determined. The routine proceeds to step 4 in order to execute the downshift without increasing the shift, and the normal shift control is executed.

  Note that step 2 functions as fail-safe, and for determining whether or not the rotation-synchronized shift control can be executed, for example, the accelerator pedal opening APO is larger than a preset value, and the amount of depression of the accelerator pedal is excessive. And the like that determine whether or not.

  FIG. 3 is a flowchart schematically showing a shift control subroutine executed in step 3 of FIG.

  First, in step 31, it is determined whether a condition for ending the downshift is satisfied. When it is determined that the downshift end condition is satisfied, the present control is terminated and the shift control according to the flowchart of FIG. 2 is resumed, whereas when it is determined that the downshift end condition is not satisfied, Control goes to step 32.

Note that step 31 functions as a downshift completion determination. For this determination, for example, the input rotation speed (hereinafter referred to as “transmission input rotation speed”) Nt and output rotation speed (hereinafter referred to as “transmission input speed”) of the transmission 4b. No) (referred to as “transmission output speed”), and the actual speed ratio i _r (= No / Nt) calculated as the speed ratio (No / Nt) is within a predetermined speed ratio range (ie, downshift). And the like that determine whether or not the gear ratio within the subsequent gear stage has been achieved, that is, whether or not the target gear stage has been substantially reached.

In step 32, it is determined whether a condition that can increase the disengagement hydraulic pressure P ₁ which was maintained at a constant shelf pressure P _a as described below is satisfied.

This determination is set in advance timing (timing) t _p, is determined by whether or reaches this timing t _p. In this embodiment, determines such timing t _p, or by whether the actual gear ratio i _r of the automatic transmission 4 reaches a predetermined speed ratio i _S a preset.

The predetermined speed ratio i _S is, for example, a speed ratio larger than the speed ratio at the time when at least half of the downshift is executed among the speed ratios from the start time t ₁ of the downshift to the end time t ₂ of the downshift. Is adopted. More preferably employs a large change gear ratio than the gear ratio at the time of downshifting from the starting time t ₁ of the downshift is executed 70%. Thus, it is possible to set the timing t _p in advance.

The beginning of the downshift, since the actual speed ratio i _r has not reached the predetermined speed ratio i _S, the process proceeds to step 33. In step 33, a capacity required for the disengagement side friction element when performing the downshift is calculated.

That is, in step 33, in cooperation with the engagement-side friction element, a constant shelf pressure P that allows the driving force Ft from the automatic transmission 4 to be obtained even if the inside of the automatic transmission 4 is not in a neutral state. to calculate the _a. Accordingly, in step 3 of FIG. 2, first, simultaneously with the command for starting the change gear shift (downshift), the release side hydraulic pressure P ₁ is not changed from the automatic transmission 4 to the neutral state without the neutral state inside the automatic transmission 4. driving force Ft (= ΔFt) is commanded to the constant shelf pressure P _a as obtained.

Therefore, even after the release side hydraulic pressure P ₁ is lowered to perform the downshift, the automatic transmission 4 does not enter the neutral state, and the driving force Ft is still generated from the automatic transmission 4. . That is, Step 3 and Step 33 in FIG. 2 correspond to the release side hydraulic pressure drop suppression means.

  The state in which the automatic transmission 4 is not in the neutral state refers to a state in which the power transmission system in the automatic transmission 4 is functioning without being disconnected. That is, the driving force ΔFt is a driving force obtained by changing the shift output rotational speed No following the transmission side input rotational speed Nt, and therefore Ft> 0. It can be set as appropriate according to the conditions, or can be changed as appropriate according to the running state.

  By the way, when the increase in the transmission input rotational speed Nt is suppressed by simply reducing the engine torque Te as in the prior art, if the decrease amount of the engine torque Te is increased, the driving force Ft is changed by the subsequent driving operation or the like. However, since the engine torque Te has decreased, it is impossible to take a quick response and there is room for improvement in responsiveness.

Therefore, in this embodiment, after the completion of step 33, returns to step 31, in step 31, whether the end condition of the downshift is satisfied, at step 32, it is possible to increase the disengagement hydraulic pressure P ₁ This control is continued until the condition is satisfied.

In step 32, when the actual gear ratio i _r is determined to have reached the predetermined gear ratio i _S, at step 34, it calculates a target value P _b of when increasing the release-side oil pressure P _1.

Target value P _b calculates the hydraulic pressure corresponding to the transmission input torque T _in post downshift, the hydraulic pressure to the target pressure, transmission input torque T _in, for example, is calculated from equation (1) below.
T _in = ΔNe × Ie (1)
ΔNe: Speed of change of engine speed Ne
Ie: Engine inertia

  Equation (1) assumes that the torque converter 4a is in a lock-up state (Ne = Nt). Therefore, in the non-lock-up state (Ne ≠ Nt), the engine rotational speed Ne is obtained from the shift input rotational speed Nt and the slip ratio of the torque converter 4a, and this is used for the calculation of the above (1).

In step 35, to calculate the pressure corresponding to the transmission input torque T _in determined at step 34, the hydraulic and target pressure P _b. Thus, in step 3 of FIG. 2, when the actual gear ratio i _r reaches a predetermined speed ratio i _S, the disengagement side pressure P _1, shelf pressure P _a from the target hydraulic pressure P _b to become as predetermined change gradient ΔG Command to increase at That is, Step 3 and Steps 33 and 34 in FIG. 2 correspond to release side hydraulic pressure increasing means.

Thus, since the predetermined gear ratio i _s, by increasing toward the disengagement side pressure P ₁ in the target hydraulic pressure P _b, the row conventionally in order to suppress the increase of the transmission input speed Nt with the downshift Even if the reduction amount of the engine torque Te is suppressed, the driving force Ft from the automatic transmission increases just before the end of the downshift. Therefore, even if a change in the driving force Ft is requested after the end of the downshift, the driving force It is possible to respond quickly to changes in Ft.

The predetermined change gradient ΔG when increasing the shelf pressure P _a at the target hydraulic pressure P _b is set in advance as appropriate in accordance with the requirements of the vehicle type or the user, or may be changed according to the running state . Also, the increase of the release side hydraulic pressure P ₁ is performed, for example, by setting a time in advance, and is performed until this set time, and then the release side hydraulic pressure P ₁ is subjected to the original shift control in order to execute the shift control (downshift control). Decrease.

On the other hand, on the engagement side friction element side, when it is determined that the downshift is started at the time point t ₁ , the engagement side hydraulic pressure P ₂ is increased to the precharge pressure P _{p, and} then the hydraulic pressure P ₂ is maintained at a certain shelf. By maintaining the pressure _Pc , the fastening side friction element is maintained in a state immediately before fastening. Then, it is determined to determine whether the target rotation speed Ne the engine speed Ne is preset (o), at time t _2, the engine speed Ne has reached the target rotation speed Ne (o) Then, the downshift is completed by raising the engagement side hydraulic pressure P ₂ to the release side hydraulic pressure P ₁ .

In the present embodiment, at time t _2, without increasing the engagement side hydraulic P ₂ at once, once, after it raised to a hydraulic P _d, which is raised at a constant gradient to the hydraulic P _e. In this case, the fastening shock accompanying the fastening operation of the fastening side friction element can be prevented.

  Here, FIG. 4 is a time chart showing the rotation-synchronized shift control according to the present invention executed according to the flowchart of FIG. 3 in a time series, whereas FIG. 5 shows a conventional rotation-synchronized shift with a neutral state. It is a time chart which shows control in time series.

According to the present invention, until, as shown in region A of FIG. 4, to start lowering of the release-side hydraulic pressure P ₁ at the start time t ₁ of the downshift, then reaches a preset timing t _p The release side hydraulic pressure P ₁ is maintained at _a constant shelf pressure Pa, so that the decrease in the hydraulic pressure P ₁ can be reduced without causing the automatic transmission 4 to be in a neutral state (Ft = 0). 4 so that the engine rotational speed Ne and the transmission input rotational speed Nt are synchronized with each other from the automatic transmission 4 as shown in the region B of FIG. The driving force Ft (= ΔFt) is obtained, and the automatic transmission 4 does not enter the neutral state.

  For this reason, according to the present invention, the driving force Ft from the automatic transmission 4 temporarily disappears even though the downshift is being performed, thereby giving the driver a feeling of idling. There is no.

On the other hand, according to the prior art, as shown in a region A ′ in FIG. 5, the release side hydraulic pressure P ₁ is completely removed at the downshift start time t ₁ , thereby showing the region B ′ in FIG. 5. As described above, the neutral state (Ft = 0) in which the driving force Ft from the automatic transmission 4 cannot be obtained at all is obtained. That is, according to the conventional technique, when the downshift is executed, the driving force Ft from the automatic transmission 4 is temporarily lost, which gives the driver a feeling of idling.

  Further, according to the present invention, there is no time from the neutral state (Ft = 0) to the generation of the driving force Ft (Ft> 0) at the time of downshift, so that the driving is performed as shown in a region E in FIG. Since the force Ft rises early, the driver does not feel uncomfortable with this time as the shift delay.

  On the other hand, in the prior art, since the inside of the automatic transmission 4 is in the neutral state, there is a time from the neutral state (Ft = 0) to the generation of the driving force Ft (Ft> 0) during the downshift. As shown in the region E ′ of FIG. 5, since the rising of the driving force Ft is delayed, the driver feels uncomfortable with this time as the shift delay.

In addition, according to the present invention, since the inside of the automatic transmission 4 does not enter a neutral state by hydraulically controlling the disengagement side friction element, it is possible to prevent so-called pulling shock accompanying the release delay of the engagement side friction element. although, in this embodiment, such a shelf pressure P _a, as the engine torque Te is high, is set to be higher. In other words, as the engine torque Te is high, (in the present embodiment, shelf pressure P _a) the lower limit value of the disengagement side hydraulic pressure P the disengagement side pressure P ₁ in order to suppress the reduction of ₁ is set such that the higher . In this case, in order to rise the shelf pressure P _a in accordance with the driver pulls the shock feeling sensitive high engine torque Te, which is effective in preventing pull-in shock.

In addition, in this embodiment, as shown in a region C of FIG. 8, after reaching a preset timing (time point t _p ), the release side hydraulic pressure P ₁ is increased to the hydraulic pressure P _b . In this case, increasing the load into the automatic transmission 4 from the transmission output shaft 5 side also reduces the rotational difference between the transmission input rotational speed Nt and the transmission output rotational speed No. Therefore, the engine torque Te increased once. When the engine speed Ne is synchronized with the transmission input speed Nt by lowering the engine speed Te, the rate of decrease in the engine torque Te can be kept small as shown in the region D of FIG.

In contrast, in the prior art, since the automatic transmission 4 is in the neutral state, there is no load from the transmission output shaft 5 side, and the hydraulic pressure of the release side hydraulic pressure P ₁ does not increase. When the engine speed Ne is synchronized with the transmission input speed Nt by reducing the torque Te, it is necessary to greatly reduce the engine torque Te as shown in a region D ′ of FIG.

  That is, in the prior art, since it is necessary to greatly reduce the engine torque Te in order to synchronize the engine rotational speed Ne with the transmission input rotational speed Nt, the engine torque becomes clear as compared with the region D in FIG. Since Te greatly falls, it takes time to return to the engine torque Te (o) required after the end of synchronization as compared with the present invention. For this reason, it is also considered that the driver feels uncomfortable with the time taken for the engine torque Te to return to the engine torque Te (o) required after the synchronization is completed as the shift delay.

That is, as in the prior art, when the increase in the transmission input rotational speed Nt is suppressed by reducing the engine torque Te, if the reduction amount of the engine torque Te is large, the driving from the automatic transmission is performed by a subsequent driving operation or the like. When the force Ft is required to be changed, there is room for improvement in its responsiveness, but if the configuration is such that the release side oil pressure P ₁ increases toward the target oil pressure P _b as in the present invention, it will be reduced. Immediately after the end of the shift, as shown in region E, the driving force Ft from the automatic transmission increases, and as a result, the responsiveness to a new request after the end of the downshift is improved as compared with the conventional case.

Therefore, if the release side hydraulic pressure P ₁ is increased toward the target hydraulic pressure P _b as in the present embodiment, the engine torque Te conventionally used to suppress the increase in the transmission input rotational speed Nt due to the downshift. even if the reduction load suppression, the downshift end t ₂ just before, the driving force Ft from the automatic transmission is increased, also the change of the driving force Ft downshifting completion after is requested, the driving force Ft Can respond quickly to changes.

In the present embodiment, the increase from shelf pressure P _a of the disengagement side pressure P _1, has been described as directed to the target hydraulic pressure P _b, according to the present invention, the target hydraulic pressure value lower than the target hydraulic pressure P _b You can also That is, according to the present invention, at least the above-described effects can be obtained if the release side hydraulic pressure P ₁ is increased.

Further, in this embodiment, the timing tp of increasing the release-side hydraulic pressure P _1, that actual gear ratio i _r of the automatic transmission 4 is the timing that has reached the value i _s a preset, relatively simple the timing Therefore, the cost can be reduced without using an expensive arithmetic unit (CPU).

Further, in this embodiment, with respect to the target hydraulic pressure P _b that has a hydraulic equivalent to the transmission input torque Tin after downshifting, release side frictional element to reduce the pressure in increasing the release-side hydraulic pressure P ₁ Therefore, stable synchronization between the engine speed Ne and the transmission input speed Nt after downshifting can be achieved without supplying excessive hydraulic pressure.

  The above is a preferred embodiment of the present invention, but various modifications can be made within the scope of the claims. For example, various types of automatic transmissions according to the present embodiment can be employed. The automatic transmission according to the present invention is not limited to a stepped automatic transmission, and may be a belt-type continuously variable transmission.

1 is a system diagram schematically showing an outline of a shift control device for an automatic transmission according to an embodiment of the present invention. It is a flowchart which shows roughly the main routine of the shift control according to this invention performed by ATCU of the form. 3 is a flowchart schematically showing a shift control subroutine executed in step 3 of FIG. 2. It is a time chart which shows the rotation synchronous transmission control which concerns on this invention performed according to the flowchart of FIG. 3 in time series. It is a time chart which shows the conventional rotation synchronous transmission control with a neutral state in time series.

Explanation of symbols

1 Engine 2 Air intake passage 3 Electric throttle valve 4 Automatic transmission
4a Lock-up torque converter
4b Stepped transmission
4c Hydraulic control unit 5 Transmission output shaft 6 Bidirectional communication line 7 Select lever
101 ECU (Engine Control Unit)
102 ATCU (automatic transmission control unit)
S ₁ Accelerator opening sensor S ₂ Engine rotation sensor S ₃ Transmission output shaft rotation sensor

Claims (5)

The friction element has a plurality of friction elements that can be engaged and released by increasing or decreasing the hydraulic pressure. The friction element is tightened by increasing the hydraulic pressure of the friction element to be fastened and the hydraulic pressure of the friction element to be released is decreased. When the downshift is executed in an automatic transmission that performs upshifting or downshifting, the engine driving force is increased to change the engine speed to the input speed of the automatic transmission after downshifting. In a shift control device for an automatic transmission to be synchronized,
Downshift start determining means for determining whether or not a downshift has started;
As a result of this determination, when it is determined that the downshift is started, the hydraulic pressure of the friction element to be released is suppressed so that at least the driving force from the automatic transmission can be obtained without causing the automatic transmission to be in the neutral state. A shift control apparatus for an automatic transmission, comprising: a release-side hydraulic pressure drop suppression means.   2. The shift control for an automatic transmission according to claim 1, wherein the release side hydraulic pressure drop suppression means increases the lower limit value of the hydraulic pressure for suppressing the hydraulic pressure drop as the engine torque increases. apparatus.   3. The pressure of the friction element to be released after suppressing the hydraulic pressure of the friction element to be released at least so that the driving force from the automatic transmission can be obtained without causing the inside of the automatic transmission to be in a neutral state. A shift control apparatus for an automatic transmission, comprising release-side hydraulic pressure increase means for increasing the hydraulic pressure to accelerate the synchronization between the engine speed and the input speed of the automatic transmission after downshifting.   In claim 3, when the release side hydraulic pressure increasing means suppresses the hydraulic pressure of the friction element to be released so that at least the driving force from the automatic transmission can be obtained without the inside of the automatic transmission being in a neutral state. A shift control apparatus for an automatic transmission, characterized in that the end of the automatic transmission is determined based on whether or not the actual transmission ratio of the automatic transmission has reached a predetermined transmission ratio set in advance.   5. The automatic transmission shift according to claim 3, wherein the release side hydraulic pressure increase means obtains a hydraulic pressure corresponding to the transmission input torque after the downshift and uses the hydraulic pressure as a target pressure. Control device.

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