JPH04140565A - Speed change control method for vehicular automatic transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a shift control method for an automatic transmission for a vehicle, and in particular, it is possible to optimally perform a shift from a neutral position to a reverse or drive position. The present invention relates to a shift control method for an automatic transmission for a vehicle.

(Prior art) An automatic transmission for a vehicle consists of an input shaft that inputs rotational force from an engine, an output shaft that outputs driving force to the driving wheels, and a structure that is arranged between these input shafts and output shafts. A rotating element such as a rotary drum or a gear, and a frictional engagement element such as a clutch or a brake that cooperates with the rotating element to control the rotation of the rotating element. Here, the frictional engagement element is
Specifically, it is a hydraulically actuated type, and the frictional engagement element is operated by receiving operating pressure based on a shift command from the selector lever or a shift command according to the driving state of the vehicle, and is connected to the input shaft. By appropriately selecting a rotating element between the output shaft and the output shaft, a desired speed change can be performed manually or automatically.

For example, in the automatic transmission described above, when the selector lever is switched from the neutral position to the reverse position, the front clutch and low/reverse brake (L/R brake) of the frictional engagement elements are both activated. The pressure of the hydraulic oil supplied to the L/R brakes, that is, the L/R supply pressure, is controlled according to a preset duty control pattern.
It is designed to improve the responsiveness of the shift and reduce shift shock.

Specifically, the L/R supply pressure of the L/R brake is controlled by a duty-controlled pressure control solenoid valve via a low/reverse control valve.

Regarding the duty control pattern, there is a preparatory duty control pattern from the shift command to eliminating the play in the operation of the frictional engagement element, that is, the L/R brake, and a preparatory duty control pattern for the actual L/R brake following this preparatory duty control pattern. It can be broadly divided into engagement duty control patterns in which the brake is actuated, and in each duty control pattern, the duty rate of the pressure control electromagnetic valve is appropriately defined as time passes.

(Problem to be Solved by the Invention) By the way, when controlling the L/R supply pressure to the L/R brake according to the duty control pattern of the pressure control solenoid valve, this duty control pattern is uniquely set. Furthermore, the relationship between the duty ratio of the pressure control electromagnetic valve and the above-mentioned L/R supply pressure varies greatly from one automatic transmission to another. Therefore, even if the L/R supply pressure to the L/R brake is determined by the duty rate at the time when control according to the engagement duty control pattern is started, that is, the initial engagement duty rate, this L/R supply pressure There will be variations in the value of .

Therefore, if the L/R supply pressure determined by the initial engagement duty rate is too high, a peak will occur in the torque fluctuation of the output shaft between the start of the shift and the end of the shift, resulting in If a good gear shift cannot be performed, or conversely, if the L/R supply pressure determined by the initial duty ratio is too low, the shift start time may become longer.

This invention was made based on the above-mentioned circumstances, and
The purpose is to provide a shift control method for an automatic transmission for a vehicle, which is capable of stabilizing changes in the torque of the output shaft and performing shifts with good feeling.

(Means for Solving the Problems) This invention provides a rotating element between an input shaft into which rotational force from an engine is input and an output shaft that outputs driving force to the driving wheels, and a rotating element that cooperates with this rotating element. and a hydraulically actuated frictional engagement element that controls the rotation of the rotating element, and when a gear change command is received, the frictional engagement element is supplied with the operating pressure determined by the preparatory duty control pattern to reduce friction. Eliminate the operational play in the engagement element, then supply the frictional engagement element with the operating pressure determined by the engagement duty control pattern,
In a vehicle automatic transmission that performs a speed change operation between an input shaft and an output shaft via a rotating element by operating a frictional engagement element, the speed change control method starts an engagement duty control pattern. The initial engagement duty rate is set so that the rotational change rate of the input shaft from the start of shifting to the end of shifting in the previous engagement duty control pattern becomes the target value for the initial engagement duty rate at the time when This is corrected by learning, and when a shift command is received this time, at the start of control in the engagement duty control pattern, the operating pressure determined according to the corrected initial engagement duty rate is supplied to the friction engagement element. ing.

(Function) According to the above-mentioned shift control method, if the rotational change rate of the input shaft deviates from the target value during the previous shift,
In order to make this rotational change rate match the target value, the initial engagement duty rate is corrected by learning. During the current gear shift, when control according to the engagement duty control pattern is started, since the initial engagement duty rate has been corrected, the operation of the frictional engagement element determined by the initial engagement duty rate is corrected. The pressure becomes appropriate, and as a result, the rate of change in rotation of the input shaft from the start of the shift to the end of the shift can be stably maintained at the target value, which also makes it possible to stabilize the torque change of the output shaft. becomes.

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

FIG. 1 shows an example of an automatic transmission for a vehicle. In the figure, reference numeral 2 indicates an engine that serves as a power source for the vehicle, and a crankshaft 4 of this engine 2 is directly connected to a pump 8 of a torque converter 6 that constitutes an automatic transmission. Pump 8 of torque converter 6 is coupled to case 16 via its turbine 10, stator 12, and one-way clutch 14. The stator 12 is allowed to rotate in the same direction as the crankshaft 4 by a one-way clutch 14, but is prevented from rotating in the opposite direction.

The torque transmitted to the turbine 12 of the torque converter 6 is first transmitted to the input shaft 20 and from the input shaft 20 to the gear transmission 22 .

Here, the gear transmission 22 has a structure that achieves four forward speeds and one reverse speed.

The gear transmission 22 includes three sets of clutches 24, 26° 28
．． 2 sets of brakes 30, 32. 1 set of one-way clutch 3
4, and a set of Ravigneau-type planetary gear mechanism 36.

The planetary gear mechanism 36 includes a ring gear 38, a long pinion gear 40, a short pinion gear 42, and a carrier 48 that rotatably supports both pinion gears 40 and 42. This carrier 48 itself is also rotatably supported. The ring gear 38 is connected to the output shaft 50
is connected to. On the other hand, a front clutch 44 is connected to the input shaft 20 via a kickdown drum 52 and the front clutch 24. Further, a rear sun gear 46 is connected to the input shaft 20 via a rear clutch 26.

The carrier 48 described above is connected to the case 16 via a low/reverse brake (hereinafter referred to as L/R brake) 32 and a one-way clutch 34, which are functionally arranged in parallel. 22 is connected to the input shaft 20 via a four-speed clutch 28 disposed at the rear end thereof.

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

Torque transmitted from the input shaft 20 to the output shaft 50 via the planetary gear mechanism 36 is transmitted to the output gear 60 which is integrally fixed to the output shaft 50.
0 to the driven gear 64 via the idle gear 62. Furthermore, the torque transmitted to the driven gear 64 is transmitted to the differential gear device 72 via a transfer shaft 66 to which the driven gear 64 is attached, a helical gear 68 attached to this transfer shaft 66, A drive shaft 79 of a drive wheel is connected to this differential gear device 72.

Each of the clutches and brakes, which are the frictional engagement elements described above, is combined with a hydraulically actuated actuator consisting of a piston device or a servo device for engagement, and each actuator is connected to an oil pump (not shown). It is operated by hydraulic pressure generated from the The oil pump is driven by the engine 2, and the oil pump is driven by the torque converter 6.
It is also connected to the pump 8.

Therefore, the hydraulic oil from the oil pump is selectively supplied to each clutch and brake according to various operating conditions by a hydraulic control device, which will be described later. One gear shift is achieved.

For example, when the selector lever of the automatic transmission is switched from the neutral position to the reverse position, the front clutch 24 and the L/R brake 32 are operated; When the vehicle is switched from the neutral position to the drive position, the rear clutch 26 is operated.

Next, referring to FIG. 2, the front clutch 24, L
An electro-hydraulic control circuit that supplies hydraulic oil to the /R brake 32 and rear clutch 26 is schematically illustrated. The overall structure and operation of this electro-hydraulic control circuit were disclosed in Japanese Patent Application Laid-open No. 5
Since this is already known from Japanese Patent No. 8-46258, etc., the hydraulic control circuits for other brakes and clutches are omitted in FIG.

In FIG. 2, reference numeral 80 indicates a manual valve operated by a selector lever of an automatic transmission, and this manual valve 80 has an inlet boat 82 connected to an oil passage 8.
Connected to 4. This oil passage 84 is supplied with hydraulic oil that is generated from the oil pump described above and whose pressure is regulated by a regulator valve (not shown).

The manual valve 80 is provided with outlet ports 86 and 88, one outlet port 86 is connected to the front clutch 24 via an oil passage 90, and the other outlet port 88 is connected to an oil passage 92. via the N-R control valve 94, i.e., the inlet port 96 of this valve 94.
It is connected to the.

An outlet port 98 of the N-R control valve 94 is connected to the L/R brake 32 via an oil passage 100. In addition, from the part on the aroport 98 side of the oil passage 100,
A branch oil passage 102 is branched, and this branch oil passage 102
is connected to the oil passage 92. In the branch oil path 102,
A check valve 104 that opens only towards the oil path 92 side is inserted.

Furthermore, in the N-R control valve 94, in FIG.
A control room 106 located at the right end is provided. The control chamber 106 is supplied with hydraulic oil whose pressure has been regulated from an oil pump via an oil passage 108.

The control chamber 106 is connected to a pressure control valve 112, that is, a control chamber 114 of the pressure control valve 112 via an oil passage 110. This control room 114 is located in the second
It is located at the left end of the pressure control valve 112 as seen in the diagram.
The pressure control knob 112 also includes an inlet port 116.
and an outlet port 118. This inlet port 116 is connected to the outlet boat 122 of the manual valve 80 described above via an oil passage 120, while the outlet boat 118 is connected to the rear clutch 26 via an oil passage 124. An N-D control valve 126 shown as a block is inserted in the middle of the oil passage 124.

Note that, in reality, various valves such as shift valves and control valves are inserted in the oil passages 90, 100.12, but they are not shown in FIG. In addition, in the valve shown in FIG. 2, the symbol EX indicates an oil drain port, and this oil drain port (EX) is connected to an oil pan (not shown) and is connected to the oil passage 108 from the middle of the oil passage 108 mentioned above. A pressure control oil passage 128 extends therein, and this pressure control oil passage 128 is connected to an oil pan. In the middle of the pressure control oil passage 128, there is a pressure control electromagnetic knob (PC3
V) 130 is inserted. This pressure control solenoid valve 130 is connected to the control chambers 106 and 1 of the N-R control valve 94 and the pressure control valve 112 through the oil passage 128.
This is for controlling the pressure supplied to 14. That is, the pressure control solenoid valve 130 is controlled by an electronic control device (E
The electronic control unit 132 controls the switching operation of the pressure control solenoid valve 130 by duty control. Therefore, when the pressure control solenoid valve 130 is subjected to duty control, the hydraulic oil in the oil passage 108 and the control chamber 106, 114 is discharged to the low pressure side via the oil drain port Ex of the pressure control solenoid valve 130. The pressure in the control chamber 106, 114 can be regulated to a pressure corresponding to the duty rate of the pressure control solenoid valve 130.

When the pressure in the control chambers 106 and 114 is regulated in this way, the regulated pressure acts on the right end surface of the N-R control valve 94, while the pressure control valve 11
It will act on the left end face of 2.

Here, as shown in FIG. 2, in a situation where the manual valve 80 is switched from the neutral position to the reverse position, the internal space between the inlet port 82 and the ratio port 86. The passage is in a communicating state. Therefore, the inlet port 82 of the manual valve 80
The hydraulic oil supplied to the front clutch 24 is supplied from the outlet port 86 through the oil passage 90 to the front clutch 24, and the front clutch 24 is immediately activated.

Further, the hydraulic oil from the manual valve 80 is also supplied to the inlet port 96 of the N-R control valve 94 from the outlet port 88 through the oil passage 92, and from this inlet port 96, the hydraulic oil is further supplied to the outlet port 98 and the oil passage ioo. By being supplied to the L/R brake 32 through the L/R brake 32, the L/R brake 32 is operated. At this time, as described above, the regulated control pressure in the control chamber 106 is acting on the left end surface of the N-R control valve 94, so in this case, the valve spool of the N-R control valve 94 is , is moved so that the biasing force of the valve spring and the control pressure are balanced, so that the land portion of the valve spool changes, for example, the opening degree of the inlet port 96, i.e.
The valve opening degree will be adjusted. As a result, N-R
The L/R supply pressure supplied to the L/R brake 32 through the control valve 94 can be determined by the valve opening degree of the N-R control valve 94, that is, the duty rate of the pressure control solenoid valve 130. This results in
The operation of the L/R brake 32 can be controlled.

Note that when the manual valve 80 is in the reverse position, the connection between the inlet port 82 and the outlet port 122 is disconnected, so in this case, hydraulic oil is supplied to the pressure control valve 112 through the manual valve 80. It will not be done.

The electronic control device 132 described above has the pressure control solenoid valve 1
Not only the control circuit for duty-controlling the opening and closing of 32, but also a shift command output for outputting a shift command according to the selected position of the select lever, and based on the driving state of the vehicle when the select lever is in the drive position. The electronic control unit 132 also includes a control circuit, and therefore, signals from various sensors, detection switches, etc. are input to the electronic control unit 132. For example, these sensors and pressure switches include a select detection switch (inhibitor switch) that detects the selected position of the select lever, an engine rotation speed sensor that detects the rotation speed of engine 2, and a sensor that detects the throttle opening of engine 2. a throttle opening sensor that detects pressure, an input shaft rotation speed sensor that detects the rotation speed of the input shaft 20, an output shaft rotation speed sensor that detects the rotation speed of the output shaft 50, a vehicle speed sensor, and the temperature of lubricating oil in the automatic transmission. There are an oil temperature sensor, an ignition key switch, an idle switch, a parking brake switch, etc. that detect the Engine speed sensor 14
Only 0 is shown.

Next, with reference to FIG. 3 and subsequent drawings, a shift routine from when the automatic transmission is in the neutral position to when its select lever is switched to the reverse position, that is, the N-R shift routine will be explained. .

N-R shift routine First, FIG. 3 shows a flowchart of the main routine in the N-R shift routine, and in this flowchart, in step SI, the various sensors and detection switches described above are As the data from the electronic control unit 132 is read in, appropriate initialization of the electronic control unit 132 is performed.

In the next step S2, it is determined whether the select lever has been switched from the neutral position to the reverse position, that is, whether the N-R signal has been output from the select detection switch 134. In contrast, if the determination here is positive (Yes), the process advances to step S3, where the input shaft rotational speed NT of the input shaft 20 is read and the value is shown in the diagram. The data is stored as NS in a memory that does not contain data, and the next step S4 is executed. In this step S4, after the electronic control unit 132 is connected to the power supply for the first time, the N-
It is determined whether or not the R signal is output for the first time, and if this determination is positive, the next step S5 is executed; on the other hand, if the determination is negative, step S5 is bypassed and step S5 is performed. S6 is executed immediately. Therefore, step S5 is always executed only once at the beginning, and in this step, the initial value that defines the duty control pattern in the L/R supply pressure control routine in step S6, and the initial value that defines the duty control pattern in the L/R supply pressure control routine in step S6, When the learning conditions are satisfied, the initial values in the learning routine in the next step S8 are respectively set. Specifically, as initial values, α (for example, 0.15 sec) is set for the correction time td, which will be described later, β (for example, 80%) is set for the engagement initial duty rate Du, and
The correction amount Δd of this initial engagement duty rate Du is set to 0. Note that when setting the initial value of the engagement initial duty rate Du, the initial value may be varied depending on the temperature of lubricating oil in the automatic transmission. Note that each correction time td, initial engagement duty rate Du, and correction amount Δd are stored in a nonvolatile memory so that their values can be retained even when the ignition key of the engine 2 is turned off. .

On the other hand, if the determination in step S7 is negative, step S9 is executed bypassing step S8, and in this step, when the L/R supply pressure control routine of step S6 is executed, as will be described later, The values of the shift start time ti and the average speed change rate ΔNAV stored in the memory are cleared.

Next, referring to FIGS. 4 to 6, the above-mentioned L/R
A flowchart of a supply pressure control routine is shown.

In this flowchart, first, step 58 in FIG.
At step 01, the addition timer TC is set by setting the value of the addition timer TC to O, thereby enabling the addition timer TC to operate. Then, in the next step 5602, the duty rate of the pressure control solenoid valve (PCSV) 130 is set to 0%, the addition timer TC is counted for a predetermined time, and the value is added ( Step 5603). When step 5603 is completed, in the next step 5604, the value of the addition timer TC is changed to the preparation time t.
It is determined whether or not it has reached 1, and if this determination is negative,
The process returns to step 5602, and the steps after this step are repeated until the determination in step 5604 becomes positive. Therefore, as is clear from the duty rate control pattern shown in FIG. is maintained at 0%. Therefore, during the preparation time tl, N−R
The valve opening degree of the control valve 94 is maintained fully open,
Hydraulic oil will be supplied to the L/R brake 32.

If the determination in step 5604 is positive, the next step 5
Proceeding to 605, in this step, the value of the addition timer TC mentioned above is set to O, and the addition timer TC is set.
Then, the duty ratio of the pressure control solenoid valve (PCSV) 130 is set to a predetermined value D1 (step 5
606). Here, Dl is set to 40%, for example.

In the next step $508, as in step 5603, the addition timer TC counts for a predetermined time and the value is added, and then it is determined whether the value of the addition timer TC has reached the correction time td. is determined (step 5
509).

If the determination in step 8608 is negative, steps after step 5606 are repeated until the determination in step 8608 is positive. Therefore, in this case, the seventh
As shown in the figure, pressure control solenoid valve CPC5
V) The duty rate of 130 is maintained at Dl, and as a result, the N-R control valve 94 is maintained at the valve opening corresponding to the duty rate D1, and hydraulic oil is supplied to the L/R brake 32. That will happen.

Here, the preparation duty control pattern is defined from when the NR signal is output until the preparation time t1 and correction time td described above have elapsed.
When the L/R supply control routine is executed for the first time,
By carrying out step S5 of the main routine described above, the value of the correction time td is set to α described above.

When the determination of the step valve 5608 becomes positive, that is, when the duty rate of the pressure control solenoid valve 130 is controlled according to the preparation duty control pattern described above, the L/R brake 32 is controlled via the N-R control valve 94. By receiving hydraulic oil supply, its internal pressure increases,
Then, the play in the operation of the L/R brake 32 is eliminated. This means that the so-called adjustment of the hydraulic pressure to the L/R brake 32 is completed.

Proceeding from step 5608 to step 5609 in FIG. 5, the duty rate of the pressure control solenoid valve 130 is then controlled according to the engagement duty control pattern shown in FIG.

That is, in step 5609, the addition timer TCO value is
, this addition timer TC is set, and
An engagement initial duty rate Du is set as the duty rate of the pressure control solenoid valve (PC8V) 130 (step 5610).

Here, as in the case of the correction time td described above, L/R
When the supply control routine is executed for the first time, the engagement initial duty rate Du is set to β.

In the next step 5611, the input shaft rotation speed NT is read, and the rotational change rate Δ of this input shaft rotation speed NT is
N is calculated and found. Here, the rotational change rate ΔN is
Specifically, it is calculated by subtracting the input shaft rotation speed detected last time from the input shaft rotation speed detected this time.

In this way, input shaft rotational speed NT and rotational change rate ΔN
is calculated, in the next step 3612, the input shaft rotation speed NT is set to a predetermined value NB (NB<NS, for example, NB
= 0.8 NS ), and the rotational change rate ΔN is Δ
It is determined whether N<0 is satisfied. Here, immediately after the control using the engagement duty control pattern described above is started, and when step 5612 is executed for the first time, the play in the L/R brake 32 has only been eliminated, so at this point , the L/R brake 32 is still not substantially in operation. Therefore, at this point, the input shaft rotational speed NT is maintained at the rotational speed at the time when the NR signal was output, so the determination in step 5612 is negative, and in the next step 5613, The addition timer TC counts a predetermined time, and the value is added. After that, when the execution of step $613 is completed and the process proceeds to step 5614, the value of the duty rate is subtracted by a predetermined value ΔDx, and then the process returns to step $611 to perform the steps after this step. is carried out repeatedly. Here, the value of the predetermined value ΔDx is set to a value such that the duty rate decreases at a rate of lθ%/see from the start of the engagement duty control pattern, as shown in FIG. has been done.

While the steps from step 5611 to step 5614 are being repeated, the input shaft rotational speed N
When T decreases to NB as shown in FIG. 8 and reaches the shift start time S, B, at this point, step 5 is started.
The determination at 612 is positive, in which case the process advances from this step to step 5615.

In step 5615, the value of the addition timer TC, that is, the shift start time ti corresponding to the time from the start of the engagement duty control pattern to the shift start times S and B as shown in FIG. Not stored in memory.

After this, from step 5615, step 5 in FIG.
The process advances to step 616, where the duty rate is set to a predetermined value D3.

Here, the predetermined value D3 is, for example, DuxM (M>
(a constant value of 1 or more).

From step 8616, the input shaft rotation speed NT is read in the next step 8616, and the input shaft rotation speed N
It is determined whether T has decreased to a predetermined value NF (step 5617). Here, the predetermined value NF is set to a value sufficiently smaller than NB, for example, 200 rpm.

If the determination in step 8618 is negative, step 56
19, the rotational change rate ΔN of the input shaft 20 is calculated as described above, and in the next step 5620, this rotational change rate ΔN is added to the value of the integration counter SUM, and the number of times is calculated. After the value of counter C is incremented by 1, the process returns to step 5616, and the steps after this step are repeated. Of course, when step 5620 is executed for the first time, the values of the integration counter SUM and the number counter C are reset to the initial value O.

Therefore, as long as the determination in step 8618 is negative, the duty rate will be a constant value D3 as shown in FIG.
and the integration counter SUM
The value of is added by the rotational change rate ΔN calculated in step 5619, and at the same time, the number of additions is
It is counted by a number counter C.

By repeating steps 8616 to 5620, the input shaft rotation speed NT decreases due to the increase in the L/R supply pressure of the L/R brake 32.
If the determination in step 618 is positive, that is, as shown in FIG.
21, shift start time S, shift end time S from B,
The average rotational change rate ΔNAV up to F is calculated. Specifically, the average rotation rate of change ΔNAV can be calculated using the following equation.

ΔNAV=SUM/C In the next step 5622, the average rotation rate of change ΔNAV is stored in a memory (not shown), and an addition timer TC
is set with its value equal to 0 (step 5623
). After that, in step 5624, the duty rate of the pressure control solenoid valve (PC3V) l30 is set to a predetermined value Δ
Only DY is subtracted.

In the next step 5625, the value of the addition timer TC is calculated for a predetermined period of time, and the value is added.In step 5626, the value of the addition timer TC is increased to a predetermined value tF.
It is determined whether or not the value is greater than or equal to the value. If the determination here is negative, the steps after step 5624 are repeatedly executed. Therefore, the duty rate is the predetermined value ΔD
V, and in this case, the predetermined value ΔDy is the seventh
As shown in the figure, from the shift end point S, F to 2
It is set to a value such that the duty rate decreases at a rate of 5%/SeC.

While the steps from step 624 are being repeated, if the determination at step 8626 becomes positive, the process returns to the main routine shown in FIG. 4 described above and the next step S7 is executed.

In step S7, as described above, it is determined whether the driving state of the vehicle satisfies the learning conditions, and the learning conditions include, for example, the following.

1. The idle switch must be kept in the ON state until the above-mentioned shift is completed.

2. Engine speed is 85 Orpm or less, and N
- In the period from the time when the R signal is output until, for example, 2 see, the engine speed changes by ±50 rpm.
Must be within m.

3. The lubricating oil temperature of the automatic transmission must be in the range of 60°C to 900°C.

4. The vehicle speed detected by the vehicle speed sensor is 0, and the parking brake detection switch is off.

5. The N-R signal is not output for the first time after the ignition key is turned on.

The automatic transmission must be in the neutral position, for example, for 2 seas before the 6°N-R signal is output.

Therefore, when the L/R supply pressure control routine in step S6 is executed for the first time or the first time after the ignition key is turned on, the determination in step S7 is negative. Proceed to step S9,
As described above, the values of the shift start time ti and the average rotational change rate ΔNAV stored in the memory are cleared.

However, if the determination in step S7 is positive, the process advances to the next step S8, and a learning routine is executed.

The learning routine is shown in the flowcharts of FIGS. 9 through 12. In this flowchart, in step 5801 of FIG. 9, in the L/R supply pressure control routine described above, the deviation between the stored shift start time t1 and the target value tO (for example, 0.25ec) is determined. Δt is calculated, and in the next step 58Q2, it is determined whether the deviation Δt is 0 or more.

If the determination in step 5802 is positive, step 58
At step 03, the correction amount Δtb is calculated based on the following equation.

Δtb=1×Δt Here, K1 is a constant, and is set to 0.5, for example.

On the other hand, if the determination in step $802 is negative, the correction amount Δtb is calculated in step 5804 based on the following equation.

Δtb=2×Δt Here, K2 is a constant, and is set to l, for example.

Therefore, the correction amount Δtb and the deviation Δt calculated in step 5803 or 5804 have the relationship shown in FIG. 13.

When the next step 5805 is reached from either step 5803 or 5804, in this step, the correction amount cumulative value tb of the correction amount Δtb is calculated based on the following equation.

tb=tb+Δtb Here, the correction amount cumulative value tb is stored in a nonvolatile memory, and its initial value is set to 0 when this learning routine is first executed. .

After this, in the next step 5806, the correction time td is calculated from the correction amount cumulative value tb based on the following equation.

td = td + tb Here, until the learning routine is executed for the first time, the value of the correction time td is the initial value α (0, 15 se
c).

When the correction time td is determined in this way, in the next step $807, it is determined whether the correction time td is less than or equal to a predetermined time tS (for example, 0.5 sec), and if this determination is positive, , proceed to the next step in FIG. 10; however, if the determination is negative, step 5
After 809, the process proceeds to the next step in FIG. In step 5809, a predetermined time t is added to the correction time td.
5 is set.

In step 5810 of FIG. 10, the oil temperature TEM of the lubricating oil in the automatic transmission changes from T2O (for example, 2°C) to T2.
It is determined whether the temperature is within the range of O (for example, 60°C),
If this determination is positive, in the next step 5811,
The value of the correction time td is a predetermined time t3 (for example, 0.3
sec ) and the process proceeds to step 3812; however, if the determination at step 5810 is negative, step 5812 is performed directly from this step.

In step 5812, it is determined whether or not the correction time td is greater than 0. If the determination result is positive, the value of the correction time td is stored in the non-volatile memory and held in the next step 5813. On the other hand, if the determination result is negative, in step $814, the correction time td
After the value of is set to 0, step 5813 will be executed.

When the learning correction of the correction time td is completed as described above, next, the process proceeds to the steps related to the learning correction of the engagement initial duty rate Du shown in FIGS. 11 and 12,
First, in step 5815 in FIG.
The deviation ΔN between the average rotation rate of change ΔNAV obtained in the supply pressure control routine and the target value ΔNAVO (for example, -55 rev/sec) is calculated based on the following equation.

ΔN = ΔNAV−ΔNAVO In the next step 8816, it is determined whether the deviation ΔN is 0 or more. If this determination is positive, that is, when the rate of decrease in the input shaft rotational speed NT is smaller than the target value, step $ Proceeding to 817, in this step, the target correction amount Δdo
is calculated by the following formula.

Δdo = 3 XΔN Here, K3 is a constant, for example -0.4%/re
v/sec'.

On the other hand, if the determination in step 5816 is negative, that is, if the rate of decrease in the input rotational speed NT is greater than the target value,
At step 8818, the target correction amount Δdo is calculated using the following equation.

△do = 4 XΔN Here, K4 is a constant, for example -0,1%/re
v/sec'.

Therefore, the relationship between the target correction amount Δdo and the deviation ΔN is
The result will be as shown in Figure 4.

From steps 5817 and 5818, step 5819
However, here, it is determined whether the target correction amount Δdo is less than or equal to a predetermined value Δcil (for example, 1.2%), and if this determination is positive, in the next step 5820, the target correction amount is It is determined whether the amount ΔdO is greater than or equal to a predetermined value −Δd1. If the determination results in steps 5819 and 5820 are both positive, the process advances to step 5821. However, if the determination in step 5819 is negative, Δdl is substituted for the target correction amount Δdo in step 5822, leading to step 5821;
If the determination in step 20 is negative, one Δdl is substituted for the target correction amount ΔdO in step 5823, and step 582
It will reach 1.

In step 5821, based on the following equation, the target correction amount Δd
From o to the above-mentioned correction amount Δd of the initial engagement duty rate Du.
is calculated.

Δd=Δd+Δd.

Here, when this learning routine is executed for the first time, the value of the correction amount Δd is set to the initial value 0 as described above, so when step 5821 is repeatedly executed, the correction amount Δd becomes , becomes the cumulative value of the target correction amount Δdo.

In the next step 5824 shown in FIG. 12, it is determined whether the correction amount Δd is greater than or equal to a predetermined value Δd12 (for example, 12.5%), and if this determination is negative, the next step 5
At step 825, it is determined whether the correction amount Δd is less than or equal to a predetermined value −Δd12. Here, too, if the determination is negative, step 8826 is immediately executed.

However, if the determination in step 5824 is positive, the predetermined value Δd12 is substituted for the correction amount Δd in step 5827, and then step 8826 is executed; on the other hand, if the determination in step 5825 is positive, After the predetermined value -Δd12 is substituted for the correction amount Δd in step 8828, step $826 is executed.

Then, in step 8826, the engagement initial duty rate Du is calculated based on the following equation.

Du wDu+Δd After this, the process proceeds to step 5829, in which the engagement initial duty rate Du is set to a predetermined value D2 (for example, 85
%) or more is determined, and if this determination is negative,
However, if the determination is positive, a predetermined value D2 is assigned to the initial engagement duty rate Du in step 5831, and then step 5830 is performed.
It will proceed to 830.

In step 5830, the engagement initial duty rate Du determined in the previous step is stored in the nonvolatile memory,
Then, this learning routine is ended and the process returns to the main routine shown in FIG. 3, and the NR shift main routine is completed.

According to the N-R shift main routine of the embodiment described above, when the learning routine is executed, the seventh
In the duty rate control pattern shown in the figure, based on the deviation Δt between the opening at the start of the shift and the target value to,
The correction time td is corrected according to academic principles, and the deviation ΔN between the average rotational speed change rate ΔNAV and its target value ΔN AVO
Based on this, the engagement initial duty rate Du is also corrected by learning.

Therefore, when the learning routine of the NR shift main routine is repeatedly executed in response to the output of the NR signal,
The correction time td and the initial engagement duty rate Du obtained by the learning correction are both appropriate values, and in the next N-R shift, the shift start time ti is made to match the target value to, and the average Since the rotational speed change rate ΔNAV can also be made to match its target value ΔNAVO, N
-H shift responsiveness is stabilized, and N-R shift feeling can also be improved.

To be more specific about this point, by appropriately learning and correcting the correction time td, the operational play in the L/R brake 32 is properly controlled after being controlled according to the preparation duty control pattern described above. However, when control is subsequently performed according to the engagement duty control pattern, the shift start time ti is equal to the target value to
Therefore, stable response of shifting can be obtained.

On the other hand, if the engagement initial duty rate Du is appropriately learned and corrected, in this embodiment, the shift start times S and B
Since the duty rate D3 at is also appropriately corrected based on the corrected initial engagement duty rate Du,
The duty ratio D3 during the shift from the shift start time S, B to the shift end time S, F can be appropriately corrected, and the average rotation rate of the input shaft 20 during the shift, that is, the rotation of the input shaft 20, can be appropriately corrected. The deceleration can be matched exactly to its target value. Therefore, during gear shifting, it is possible to prevent a peak from occurring in the output torque change from the output shaft 50, smooth the output torque change, and obtain a stable shift feeling.

Note that the solid lines in FIGS. 15 and 16 indicate the L/R supply pressure control routine when the L/R supply pressure control routine of this embodiment is executed.
Changes in the supply pressure and changes in the torque of the output shaft 50 are shown respectively, and the broken lines in FIGS. 15 and 16 indicate changes in the L/R supply pressure and changes in the torque of the output shaft 50 in the conventional case. are shown respectively. Incidentally, the broken lines in FIGS. 7 and 8 also indicate the conventional case.

This invention is not limited to the one embodiment described above, and various modifications are possible. For example, in one embodiment:
Although the correction time td is corrected by learning from the deviation Δt between the shift start time ti and the target value to, the present invention is not limited to this, and the preparation time tl in the preparation duty control pattern may be corrected by learning. You can.

Further, the engagement duty control pattern is not limited to the one shown by the solid line in FIG. 7, but may be a pattern shown by the broken line in FIG.

Furthermore, the present invention is not only applicable when the automatic transmission is switched from the neutral position to the reverse position, but is equally applicable even when the automatic transmission is switched from the neutral position to the drive position. In this case, the pressure is duty controlled not by the L/R brake 32 but by the rear clutch 32, and this rear clutch 32 has a pressure control solenoid valve 1.
Hydraulic oil whose duty is controlled by the pressure control valve 30 and the pressure control valve 112 is supplied through the manual valve 80 and the N-D control valve 126.

(Effects of the Invention) As explained above, according to the shift control method for an automatic transmission for a vehicle of the present invention, when a shift command was previously received, during control using an engagement duty control pattern, from the time of shift start. Since the engagement initial duty rate is corrected by learning so that the rotation speed change rate of the input shaft until the end of the shift becomes the target value, this time, when the shift command is received, the engagement duty control pattern is corrected. When control is started, even if there is variation between the duty rate and the working pressure to the frictional engagement element, the working pressure to the frictional engagement element is determined according to the corrected initial engagement duty rate. As a result, the value of this operating pressure becomes appropriate, thereby producing excellent effects such as stabilizing the 4° change in torque of the output shaft and improving the feeling during gear shifting.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic diagram of the automatic transmission; FIG. 2 is a schematic diagram of the hydraulic circuit from the front clutch to the low/reverse brake and the rear clutch; FIG. 4 is a flowchart showing the N-R shift main routine, FIGS. 4 to 6 are flowcharts showing the L/R supply pressure control routine, and FIG. 7 is a duty control pattern consisting of preparation and engagement duty control patterns. A graph showing the whole, FIG. 8, is a graph showing changes in the input shaft rotation speed of the automatic transmission with respect to time when the supply pressure of the low/reverse brake is controlled according to the duty control pattern shown in FIG. 7, and FIGS. FIG. 12 is a flowchart showing the learning routine, FIG. 13 is a graph showing the relationship between the deviation Δt and the correction amount Δtb, and FIG. 14 is a graph showing the relationship between the deviation Δt and the correction amount Δtb.
A graph showing the relationship between N and the target correction amount Δdo, FIG. 15 is a graph showing the supply pressure change of the low/reverse brake controlled according to the duty control pattern of FIG. 7,
FIG. 16 is a graph showing changes in the output shaft torque of the automatic transmission when the supply pressure of the low/reverse brake is controlled according to the duty control pattern of FIG. 7. 24...Front clutch, 26...Rear clutch, 32...L/R brake, 80...Manual valve, 94...N-R control valve, 112...
...Pressure control valve, 126...N-D control valve, 130...Pressure control solenoid valve, 132...
・Electronic control device, 134...Select detection switch,
138... Input shaft rotation speed sensor, 140... Engine rotation speed sensor. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagato Figure 3 Figure 4 Figure 6 Figure 7 NR signal Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13

Claims (1)

[Claims] A rotating element between an input shaft into which rotational force from the engine is input and an output shaft that outputs driving force to the driving wheels, and a rotating element that cooperates with this rotating element to control the rotation of the rotating element. A hydraulically actuated frictional engagement element to be controlled, and when a gear shift command is received, the operating pressure determined by the preparatory duty control pattern is supplied to the frictional engagement element to operate the frictional engagement element. After this, the friction engagement element is actuated by supplying the operating pressure determined by the engagement duty control pattern to the friction engagement element, thereby connecting the input shaft and output via the rotating element. In a vehicle automatic transmission that performs a gear shift operation between a shaft and a shaft, the initial engagement duty rate at the time the engagement duty control pattern is started is compared with the initial engagement duty rate from the start of gear shifting during the previous engagement duty control pattern. The initial engagement duty rate is corrected by learning so that the rotational change rate of the input shaft until the end of the shift is the target value, and when a shift command is received this time and when control starts using the engagement duty control pattern. ,
A shift control method for an automatic transmission for a vehicle, characterized in that a working pressure determined according to a corrected initial engagement duty rate is supplied to a frictional engagement element.