JPH08200489A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE: To rationalize judgment of a start of engaging a next stage engaging element at poweroff downshift time in a control device for an automatic transmission. CONSTITUTION: An automatic transmission has a speed change mechanism 1 provided with a plurality of engaging elements B0 to B3, C0 to C2 to release of the elements the high speed shift side engaging elements B1, B2 to perform a downshift by engaging the low speed shift side engaging element B3, control device comprising an ECU3 of controlling this speed change mechanism based on a speed change command, input rotational speed sensor Sn1 of the speed change mechanism 1 and throttle opening sensor Sn2 of detecting a throttle opening of an engine E. The ECU3, detecting at any time an output signal from the input rotational speed sensor Sn1 when placed a throttle opening in a fully closed condition further when output a speed change command of downshift, has a judging means of judging the point of time, an input side rotational speed rises after lowering down, as a start of engaging the low speed shift side engaging element B3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission, and more particularly to a control start timing determining means for executing various controls in the control device.

[0002]

2. Description of the Related Art Conventionally, in an automatic transmission in which a plurality of engaging elements are selectively engaged and disengaged to achieve each shift speed, various demands at the time of shifting such as reduction of shift shock and reduction of shift time are met. Therefore, various controls (for example, engine torque control and line pressure control) that change the shift characteristics are performed. When the starting point of such various control switching (that is, start, end or change) timing is the start of engagement of the next-stage engagement element, a shift command is normally issued to determine the engagement start. Operate a timer etc. starting from the time point,
The judgment to start the engagement of the next-stage engagement element after a predetermined time has been used.

However, in order to further improve the control accuracy, it is preferable to determine the engagement start of the next-stage engagement element based on the actual progress state of the gear shift. Therefore, the input side rotation speed calculated from the gear ratio and the output side rotation speed in the gear stage before the shift is compared with the input side rotation speed during the shift, and when the former exceeds the latter, the next stage engagement element Japanese Patent Laid-Open No. 1-21-298 discloses a technique for performing control based on the determination that engagement is started
It is disclosed in Japanese Patent No. 66025. In this example, specifically, at the time of power-on upshift, the input rotation speed value (Ne1) calculated from the previous gear ratio (that is, the low speed gear ratio) and the actual measurement value of the output shaft rotation speed, and the engine rotation speed during the gear shift. N is compared with the input rotation speed value (Ne) measured from the speed.
When e <Ne1, the engagement start (that is, inertia phase start) of the next-stage (that is, high-speed stage) engagement element is determined, and control that is the starting point of the engine torque control switching start timing is performed.

[0004]

By the way, the judgment method disclosed in the above-mentioned prior art is effective at the time of power-on upshift, but the front stage is set to the high-speed stage, and its engaging element is released, and the next stage is set to the low-speed stage. In the downshift that is achieved by engaging the engagement elements of the gears, when the preceding-stage engagement elements are released, the gear ratio is involved before the engagement of the next-stage engagement elements. A neutral state (for example, due to idling of the one-way clutch) may occur. If the power is off at this time, the input side rotation speed will decrease. , The engagement start determination is erroneously made by detecting the state where the input side rotation speed does not match the gear ratio, although the engagement element of the next stage is not actually started. , Starting from this When performing the switching of the control, rather or shift shock is increased, etc. in which the shift time or longer, the various control may become impossible to perform accurately.

Therefore, the present invention reliably detects the start time of engagement of the low speed stage side engagement element by monitoring the change of the input rotation speed during the power off downshift, and the next stage accompanying the occurrence of the neutral state. A main object of the present invention is to provide a control device for an automatic transmission that prevents erroneous detection at the start of engagement of engagement elements. Next, it is a more specific object of the present invention to speed up the shift at the power-off downshift by performing the line pressure control by the above control device.

[0006]

In order to solve the above-mentioned problems, the present invention comprises a plurality of engaging elements, and among the plurality of engaging elements, the high-speed step-side engaging element is released to release the low-speed step. In an automatic transmission having a speed change mechanism that performs a downshift by engaging engagement elements and a control device that controls the speed change mechanism based on a speed change command, an input rotation that detects an input side rotation speed of the speed change mechanism. And a throttle opening sensor that detects a throttle opening of an engine that drives the transmission mechanism, and the control device is configured such that the throttle opening is fully closed and the downshift gearshift command is issued. When it is made, the output signal from the input rotation speed sensor is detected at any time, and in the detection, the engagement of the low speed stage side engagement element is started at the time when the input side rotation speed decreases and then rises. Judgment It characterized by having a determining means that.

Next, the present invention comprises a plurality of engaging elements,
A shift mechanism that performs a downshift by releasing a high speed side engagement element and engaging a low speed side engagement element of the plurality of engagement elements, and supplying the plurality of engagement elements to a hydraulic servo. In an automatic transmission having a control device for controlling hydraulic pressure based on a shift command, an input speed sensor for detecting an input side speed of the speed change mechanism, and a throttle for detecting a throttle opening of an engine for driving the speed change mechanism. An opening sensor, the control device detects the output signal from the input rotation speed sensor at any time when the throttle opening is in the fully closed state and when a shift command for the downshift is made, In the detection, there is a determination unit that determines that the engagement of the low-speed-stage side engagement element is started at the time when the input side rotation speed is decreased and then increased, and from the shift command to the engagement start judgment. During, characterized in that for boosting the line pressure supplied to the hydraulic servo of the low speed stage engaging member.

[0008]

In the control device for an automatic transmission according to the first aspect of the present invention having the above-mentioned structure, the high speed stage side engagement is performed at the time of downshifting with the throttle opening fully closed. Detects the input rotation speed that drops with the release of the compound element,
Since it is determined that the engagement of the low-speed-stage side engagement element is started at the time when the input speed changes from decreasing to increasing, the speed change mechanism becomes in the neutral state, and the input-side speed does not match the gear ratio. Also, the engagement start determination of the low speed stage side engagement element can be reliably performed. Therefore, according to the present invention, it is possible to prevent erroneous determination that the engagement is started even though the engagement of the low speed stage side engagement element is not actually started.

According to the structure of claim 2,
Since the engagement start point of the next-stage engagement element is determined more accurately than in the prior art, it becomes possible to perform accurate control, and the engagement of the low-speed stage-side engagement element can be performed based on the shift command. By increasing the line pressure supplied to the hydraulic servo of the low speed side engagement element until the start, the shift time can be shortened and the shift feeling can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown by a skeleton in FIG. 1, this automatic transmission includes a plurality of engagement elements B0-B3, C0-C2, and among the plurality of engagement elements B0-B3, C0-C2, a high-speed gear side engagement element. B1 and B2 are released to engage the low speed stage side engagement element B.
Transmission mechanism 1 for downshifting by engaging 3
Similarly, as shown in a block diagram in the figure, the automatic shift control for controlling the speed change mechanism 1 based on the shift command by controlling the hydraulic pressure supplied to the hydraulic servos of the plurality of engagement elements B0 to B3 and C0 to C2. It has a control device including a computer (hereinafter abbreviated as ECU) 3 and a hydraulic control circuit 2. The automatic transmission further includes an input rotation speed sensor Sn1 that detects the input side rotation speed of the transmission mechanism 1 and a throttle opening sensor Sn2 that detects the throttle opening of the engine E that drives the transmission mechanism 1. The ECU 3 constantly detects the output signal from the input rotation speed sensor Sn1 when the throttle opening is fully closed and a downshift gear shift command is issued, and after the detection, the input side rotation speed is lowered. It has a judgment means as a program for judging that the engagement of the low speed stage side engagement element B3 is started at the time of rising. In the control device in this example, the line pressure supplied from the hydraulic control circuit 2 to the hydraulic servo of the low speed stage side engagement element B3 is pressure-controlled from the shift command to the engagement start determination.

Further, the detailed configuration of each unit will be sequentially described. First, the speed change mechanism 1 of the automatic transmission is composed of a torque converter T, an overdrive unit D, and a main speed change unit M, as shown by a skeleton in FIG. The overdrive unit D is provided with a carrier 02 that is connected to the input shaft X and supports the planetary pinion 01, a sun gear 03, and a ring gear 04 that is connected to the intermediate shaft Y that is connected to the main transmission unit M. 02 and the sun gear 03, a wet multi-plate overdrive direct clutch C0 and a freewheel type one-way clutch F0 are provided in parallel.
A wet multi-plate overdrive brake B0 is arranged between the sun gear 03 and the transmission case H.

The main transmission unit M also has a carrier 12 which is connected to the output shaft Z and supports the planetary pinion 11.
And a sun gear 14 integrally formed with the sun gear 13,
A ring gear 15 connected to the intermediate shaft Y via a wet multi-plate forward clutch C1 is provided, and a wet multi-plate direct clutch C2 is interposed between the intermediate shaft Y and the sun gear 13, and the sun gear 13 and the case H. A second coast brake B1 made up of a band brake is interposed between the sun gear 13 and the case H, and a wet multi-plate second brake B2 is disposed between the sun gear 13 and the case H via a freewheel type one-way clutch F1. In addition, the carrier 17 supporting the planetary pinion 16 and the carrier 1
2 and a ring gear 18 connected to the output shaft Z, and a wet multi-plate fast and reverse brake B3 and a freewheel type one-way clutch F2 are arranged in parallel between the carrier 17 and the case H. It is said that.

Next, the overall configuration of the ECU 3 will be described. As shown by a block in FIG. 2, the ECU 3 receives the sensor signals from various input detection devices arranged in each part of the vehicle, passes through the input processing circuit 31, and the input interface circuit 32.
Central processing unit (CPU), read only memory (ROM), random access memory (RAM)
After the storage arithmetic processing by, the output interface circuit 33 outputs as a control signal, and various drive or processing circuits 34 are used to drive and control the speed change solenoids S1 to S3.

As an input detection device, a transmission (T / M) input rotation speed sensor S which is an input rotation speed sensor for detecting the input side rotation speed from the rotation of the engine E.
n1, a vehicle speed sensor (SP1, SP2) for detecting the output rotation speed from the rotation of the output shaft Z, the shift operation means 4 shown in FIG.
Which position is selected in the automatic gear shift (A / T) shift position sensor Sn3 for detecting which position is selected for automatic gear shift, and which is also related to the shift operating means 4 and which position for manual gear shift is selected Manual shift (M / T) shift position sensor Sn for detecting
4. A throttle opening sensor Sn arranged in the engine E for detecting the degree of throttle opening by a potentiometer
2. A brake switch (SW) arranged in the brake pedal section for detecting a brake operation, an idle switch (IDL SW) arranged in the throttle opening sensor for detecting that the throttle is fully closed, an accelerator pedal section or a throttle. A kickdown switch (K / DSW), which is arranged in the opening sensor section and detects that the throttle is fully opened and kickdown is required, a transmission (T / M) which is installed in the transmission and detects the transmission oil temperature. Equipped with an oil temperature sensor. Although the input rotation speed sensor Sn1 detects the input rotation speed from the engine rotation speed in this example, the present invention is not limited to this.
It is also possible to detect either the / M speed or the speed of the clutch C1, the carrier 02 and the sun gear 03.

On the other hand, on the output side, the solenoids (S1 to S3) of the solenoid valves for switching the shift valves (not shown) in the hydraulic control circuit 2 according to the gears, the lockup engagement / release pressure, and the accumulator back are respectively provided. Solenoid of linear solenoid valve that controls pressure and line pressure (SLU,
SLN, SLT), a solenoid drive circuit that generates a predetermined voltage or current, and a monitor circuit that checks the operation of each solenoid, determines a failure and performs self-diagnosis, an electronic control unit (EF) for engine control.
To I), a torque reduction input / output processing circuit that generates a signal that temporarily reduces the torque generated by the engine and a processing circuit that inputs the engine speed, and a self-diagnosis result is output when the ECU 3 fails in order to alleviate shock during shifting. There is a DG input / output processing circuit for the DG checker and a display drive circuit for the display device that displays the state of the transmission.

Next, since the shift operating means 4 may have various known structures, a detailed description of the structure will be omitted, but generally speaking, the shift lever 41 shown in FIG. It can be rocked back and forth and tilted left and right with respect to the side support member, and is connected to a manual valve of the automatic transmission through a link mechanism. And in the link mechanism,
An engaging / disengaging mechanism for connecting / disconnecting the link mechanism and the shift lever 41 is interposed. The engagement / disengagement mechanism includes an I-shaped pattern for automatic shifting of the shift lever 41 and the link mechanism,
It is separated by tilting the shift lever 41 left and right at the connecting portion with the H-shaped pattern for manual shifting.
Therefore, at the time of the range selection operation of the automatic shift, the displacement of the shift lever 41 is mechanically transmitted to the manual valve for switching, and the automatic shift position sensor Sn which is usually a neutral start switch.
3 is detected and input to the ECU 3.

On the other hand, during the manual gear shift position selecting operation, the displacement of the shift lever 41 is arranged at the end position of the H-shaped pattern for the manual gear shift, and the limit switch for detecting the shift lever 41 reaching the position. 4 etc.
It is detected by the individual position sensors Sn4-1 to Sn4-4 and input to the ECU 3. The inputs from these sensors Sn4 are learned from the example of the shift pattern of the manual transmission in the process in the ECU 3, and the left front is the first speed, the left rear is the second speed, the right front is the third speed, and the right rear is the fourth speed. It is recognized that each gear stage is selected by the ON signals of the position sensors Sn4-1 to Sn4-4 corresponding to the position.

FIG. 4 shows that the solenoids S1 to S3 of the solenoid valves are turned on at each position of the shift operation means 4, that is, at each position of a manual valve (not shown) in the hydraulic control circuit 2 (indicated by a circle in the diagram). ) • Off (indicated by X in the diagram) and engagement (indicated by O in the diagram) of each clutch C0 to C2 and brake B0 to B3 of the gear train • Release (indicated by X in the diagram) Indicates the relationship of movement.

In the automatic transmission constructed as described above, when the manual valve (not shown) of the hydraulic control circuit 2 is in the D position by operating the shift operating means 4, the solenoid S1 is turned on at the first speed (1ST). In this state, the clutch engagement pressure is supplied to the hydraulic servos of the clutch C0 and the clutch C1. At this time, in the speed change mechanism 1 shown in FIG. 1, the overdrive direct clutch C0 and the forward clutch C1 are engaged and the overdrive unit D Is directly connected and the rotation is input from the intermediate shaft Y to the ring gear 15, and this rotation is transmitted to the output shaft Z via the carrier 12, while the two sun gears 13 and 14 and the planetary pinion 1 are connected.
Although it is transmitted to the carrier 17 via 6 and tries to reverse the carrier 17, the reverse rotation is blocked by the action of the one-way clutch F2, and the rotation of the ring gear 18 corresponding to the rotation of the planetary pinion 16 is transmitted to the output shaft Z. It This is the first in the automatic shift (AUTO.) Mode of FIG.
This is the state of the high speed gear stage (1ST).

When the solenoid S2 is turned on, switching to the second speed gear (2ND) is performed. By supplying the engagement pressure to the hydraulic servo of the brake B2, the second brake B2 is newly engaged, the reaction force rotation of both sun gears 13 and 14 is blocked by the one-way clutch F1, and the planetary pinion 11 revolves. Is output to the output shaft Z via the carrier 12.

The shift to the third gear (3RD) is performed by turning off the solenoid S1. In the speed change mechanism 1,
The clutch C2 is also newly engaged, the ring gear 15 and both sun gears 13 and 14 are directly connected, the planetary pinion 11 is also directly connected, and the input shaft X, the intermediate shaft Y, and the output shaft Z rotate at a constant speed.

The shift to the fourth gear (4TH) is performed by turning off the solenoid S2. As a result, the clutch C0 is released and the brake B0 is engaged. At this time, since the sun gear 03 is fixed, the input of the carrier 02 is increased in speed by the rotation of the planetary pinion 01 and transmitted to the ring gear 04, so that the increased rotation is output to the intermediate shaft Y and the output is directly coupled. It is output from the main transmission unit M in the state as accelerated rotation of the output shaft Z.

On the other hand, at the time of downshifting, at the time of switching from the 4th gear to the 3rd gear, the overdrive direct clutch C0 is engaged, the overdrive brake B0 is released, and the 3rd gear is disengaged. When switching to 2nd gear, overdrive direct clutch C
2 is released, and the second brake B2 is released when switching from the second gear to the first gear. The shift state of each of the above gear stages is achieved.

On the other hand, in the case of the first speed (1ST) gear stage and the second speed (2ND) gear stage in the manual shift (MANU.) Mode, as shown in FIG.
O. Unlike the mode), the solenoid S3 is always turned on. As a result, in the second gear, the forward clutch C1 and the overdrive direct clutch C0
Since the second coast brake B1 is engaged in addition to the second brake B2, engine braking can be achieved by locking both sun gears 13 and 14 during coasting. Further, also in the first gear in the low (L) range of the automatic shift (AUTO) mode, the forward clutch C1, the overdrive direct clutch C0, and the first and reverse brakes B3 are engaged, so that the carrier 17 is engaged. It will be locked and the engine brake will be activated. Therefore, at the time of 2 → 1 shift down according to the control of the present embodiment, both brakes B are
1, B2 is released and the brake B3 is engaged. In the third and fourth gears in the manual shift mode, the solenoid operation and the operation of each clutch and brake are the same as in the automatic shift (AUTO.) Mode.

Next, FIG. 5 shows a general flow of arithmetic processing in the ECU 3. First, in step 1, all conditions are initialized at the start of the program. Next, in step 2, the current rotation speeds of the transmission input shaft X and the output shaft Z are calculated from the signals of the input rotation speed sensor Sn1 and the vehicle speed sensors (SP1, SP2). In step 3, the currently selected position is detected by the signal of the A / T shift position sensor (neutral start switch NSSW) Sn3. Also,
At the same time, a fail judgment of the neutral start switch is performed. In step 4, the throttle opening sensor Sn2
The current throttle opening is calculated by the signal of. In step 5, the current transmission oil temperature (ATF temperature) is calculated from the signal from the T / M oil temperature sensor.

In step 6 ', the shift position is determined by the signal from the M / T shift position sensor Sn4. In step 6, it is determined whether or not any of the M / T shift position flags corresponding to the position selected in the previous step 6'is turned on. At step 7, whether or not the M / T mode flag is turned on (M
/ T mode selection state). Step 8
Then, the A / T mode data A is read in the shift diagram data MSL stored in the ECU 3 in advance. In step 9, similarly, the A / T lockup (L-up) data A is read into the lockup (L-up) diagram data MSLP stored in advance in the ECU 3. Step 1
At 0, gear change and lockup (L-) is performed based on the data read in steps 8 and 9 and various conditions calculated previously.
up). In Step 11, Step 10
The timing of the gear shift and lockup (L-up) determined in step 3 is determined.

On the other hand, in step 12, the M / T mode flag is turned on and the M / T mode is selected. In step 13, the value of the A / T mode recovery timer is reset. In step 14, a subroutine for reading various data for M / T mode is entered. In step 15, A /
The value of the timer for returning to T mode is compared with the set value t ₁ . This is a process for preventing the M / T mode from being released during the M / T operation that involves passing through the neutral point. Step 1
In step 6, if the condition of step 15 is satisfied, the M / T mode flag is turned off and the mode returns to the A / T mode. Step 1
In step 7, determination of shift and lockup (L-up) is made based on the data read in the M / T map selection subroutine and various conditions previously calculated. In step 18, the shift and lockup (L
-Up) timing is determined.

At step 19 ', the engine brake solenoid S3 is controlled and judged according to the M / T shift position, the output required gear, and the like. In step 19, a signal is output to each solenoid (S1 to S3) according to the determination in steps 10 and 11 or steps 17, 18, and 19 'to start shifting. Step 20 is a subroutine according to the subject of the present invention, which temporarily determines the line pressure increase in order to reduce the time lag in the M / T mode. In step 21, the line pressure is controlled according to the throttle opening, and the line pressure is increased according to the determination in step 20. In step 22, as a measure against shock in the transitional state of gear shifting, the back pressure of the accumulator is set to A / T mode and M / T.
It is a subroutine for adding different control depending on the mode. In step 23, the linear solenoids (SLU, SLT, SLN) are output and controlled by the judgment and control of steps 10, 11 or 17, 18, 21, 22.

FIG. 6 shows the subroutine for determining the line pressure increase in step 20. In step 20-1, whether the M / T mode flag is turned on (M
/ T mode is selected). In step 20-2, the current gear and the newly requested gear are monitored, and if there is a difference between the two, it is determined that there is a gear shift output.

In step 20-3, step 20-2
It is determined whether the shift determined in step 3 is an upshift or a downshift. In step 20-4, it is determined whether the inertia phase has started during the upshift and the power-on downshift.

In Step 20-5, Step 20-4
When the conditions such as the inertia phase start determination by step S20 and the inertia phase start determination by step S20-8 are satisfied, the line pressure boost value corresponding to the shift is set. Step 20-6
Then, the throttle opening is fully closed, that is, idle (IDLE)
Determine if it is in a state.

In step 20-7, step 20-6
When the condition of is satisfied, the inertia phase judgment subroutine at power off downshift is entered. In step 20-8, it is determined by the subroutine of step 20-7 whether or not the inertia phase at coast down has started. Then, in step 20-9, the current input rotation speed is given as an initial value to the minimum value data of the input rotation speed when the boost control is not executed.

In step 20-10, step 20-
When the conditions such as the inertia phase start determination by 8 and the inertia phase start determination by step 20-4 are satisfied, the line pressure boosted value is cleared and the normal control value is restored.

Next, FIG. 7 shows the inertia phase start judgment subroutine at the time of the power-off downshift. In step 20-7-1, it is determined whether the current input speed is lower than the minimum value of the input speed.
In step 20-7-2, if the condition in step 20-7-1 is not satisfied, it is determined whether or not the current input rotation speed is equal to or more than the minimum input rotation speed plus α (rpm). In Step 20-7-3, Step 20-7-2
If the condition of is satisfied, it is determined that the inertia phase starts at the time of power-off downshift, and the flag is turned on. Step 2
In 0-7-4, when the condition of step 20-7-1 is satisfied, the minimum value of the input rotation speed is updated with the current input rotation speed. In step 20-7-5, if the condition in step 20-7-2 is not satisfied, the inertia phase start determination flag during power off downshift is turned off.

FIG. 8 is a time chart showing the situation of the determination made by the inertia phase start determination subroutine at the time of power-off downshift, and the line pressure (P _L ) is increased at the same time as the 2 → 1 shift command. . On the other hand, the input rotational speed (engine rotational speed Ne) maintains a substantially constant value until the high-speed stage side engaging elements, that is, the brakes B1 and B2 are released, but thereafter, from the time point indicated by the dotted line in the figure. When the brakes B1 and B2 are released, the descent is started.
Therefore, during this period, the update of the input rotation speed is continued. When the low speed gear side engagement element, that is, the brake B3 reaches engagement at the time point indicated by the alternate long and short dash line in the figure, the input rotation speed (Ne) starts to increase. Therefore, the inertia phase start determination is made after waiting for the input rotation speed (Ne) to increase by the engagement start determination value α set according to the time from the engagement to the inertia phase state, and the line pressure ( the step-up of P _L) is released. During this period, the line pressure (P _L ) is increased to accelerate the hydraulic pressure supply to the hydraulic servo of the brake B3, and the time required for engagement is shortened. After that, the input speed continues to increase, and when synchronized with the first speed gear ratio, the input speed stabilizes at a constant value higher than the input speed (Ne) at the start of control.

As described above in detail, in this automatic transmission control device, during the downshift in the state where the throttle opening is fully closed, the input rotational speed at which the brakes B1 and B2 are released and the descent is started. Since the determination is made that the engagement of the brakes B1 and B3 is started when the input rotation speed changes from the decrease to the increase, the sun gear 1 is released from the release of the brakes B1 and B2 to the engagement of the brake B3.
Even if the restraint of 3 and 14 is released and the speed change mechanism 1 enters the neutral state and the input side rotation speed does not match the gear ratio, it is possible to appropriately determine the engagement start of the brake B3. Therefore, according to this embodiment, it is possible to prevent erroneous determination that the brake B3 is started to be engaged even though the brake B3 is not actually started to be engaged. Thus, the determination of the engagement start point of the brake B3 is made more appropriately than in the prior art, so that accurate control can be performed.
Between shift command to the engagement of the brake B3 is started, by boosting the line pressure supplied to the hydraulic servo of the brake B3 (P _L), it is possible to reduce the shift time, the shift feeling Can be improved. Such shortening of the engagement time is particularly useful for improving the direct feeling for the M / T downshift operation.

By the way, in the above embodiment, the engagement of the brake B3, which is the low-speed gear side engagement element, is determined by monitoring the input rotation speed.
→ During the power-off downshift of one shift, the rotation speeds of the sun gears 13 and 14 and the carrier 17 increase as the brakes B1 and B2, which are the high-speed stage side engagement elements, are released. Therefore, it is possible to determine the engagement start of the low speed stage side engagement element, that is, the brake B3, by detecting these rotational speeds and detecting the time when the values increase and then decrease. However, when performing such detection,
As in the case of the above-described embodiment, since it is not possible to perform signal detection using the input rotation sensor normally provided conventionally, it is necessary to attach a new sensor for detecting the rotation speed of the sun gear 13, 14 or the carrier 17. Become.

The present invention has been described above in detail based on the embodiments. However, the present invention is not limited to the disclosure of the above embodiments, and various details can be specified within the scope of the matters described in the claims. Needless to say, it can be implemented by changing the target configuration. For example, in the above embodiment, the engagement start determination at the time of power off downshift according to the present invention is determined by M / T.
Although it is applied to the mode 2 → 1 shift, in the speed change mechanism according to the above embodiment, the high speed gear side engagement element is the clutch C.
2 and the low speed stage side engaging element is the brake B1 and A /
It is also possible to apply to the 3 → 2 shift in the low (L) range of the T mode. Further, the control target based on the above determination is not limited to the line pressure control, but the engine torque control as shown in the conventional example can be performed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of an embodiment of an automatic transmission according to the present invention, in which only a transmission mechanism is shown by a skeleton and the others are shown in a block form.

FIG. 2 is a block diagram showing a system configuration of an automatic shift control computer in the above embodiment.

FIG. 3 is a conceptual diagram showing a positional relationship between a shift pattern of a shift operating means and a position sensor in the above embodiment.

FIG. 4 is an operation chart of the above embodiment.

FIG. 5 is a general flowchart showing a processing process of the automatic shift control computer.

FIG. 6 is a flowchart showing a subroutine for line pressure boost determination in the above flow.

FIG. 7 is a flowchart showing a subroutine of inertia phase start determination during power-off downshift in the above flow.

FIG. 8 is a time chart showing the relationship between the shift and the line pressure boosting output according to the above flow.

[Explanation of symbols]

E engine 1 speed change mechanism 2 hydraulic control circuit (control device) 3 automatic speed change control computer (ECU) (control device) B0 to B3 brake (engagement element) B1 second coast brake (high speed gear side engagement element) B2 second brake ( High speed gear side engagement element) B3 Fast and reverse brake (low speed gear side engagement element) C0-C2 Clutch (engagement element) Sn1 Input speed sensor (input speed sensor) Sn2 Throttle opening sensor

Claims (2)

[Claims] 1. A transmission mechanism comprising a plurality of engagement elements, wherein a high-speed-stage-side engagement element is released and a low-speed-stage-side engagement element is engaged among the plurality of engagement elements to perform a downshift. In an automatic transmission having a control device that controls the speed change mechanism based on a speed change command, an input speed sensor that detects an input side speed of the speed change mechanism and a throttle opening of an engine that drives the speed change mechanism. A throttle opening sensor for detecting, wherein the control device outputs the output signal from the input rotation speed sensor at any time when the throttle opening is fully closed and a downshift gear shift command is issued. The automatic transmission control system is characterized by having a determination means for detecting that the engagement of the low speed stage side engagement element is started at the time when the input side rotation speed decreases and then rises in the detection. Apparatus. 2. A transmission mechanism comprising a plurality of engagement elements, wherein a high-speed-stage-side engagement element is released and a low-speed-stage-side engagement element is engaged among the plurality of engagement elements to perform a downshift. ,
In an automatic transmission having a control device that controls the hydraulic pressure supplied to the hydraulic servos of the plurality of engagement elements based on a shift command, an input speed sensor that detects an input side speed of the speed change mechanism, and the speed change mechanism. A throttle opening sensor for detecting a throttle opening of an engine for driving the engine, wherein the controller is configured to input the input when the throttle opening is fully closed and a downshift gear shift command is issued. An output signal from the rotation speed sensor is detected at any time, and in the detection, there is a determination means for determining the time point at which the input side rotation speed decreases and then increases to determine that the engagement of the low speed stage side engagement element has started. A control device for an automatic transmission, wherein the line pressure supplied to the hydraulic servo of the low speed stage side engagement element is increased during the period from the shift command to the engagement start determination.