JPH0492154A - Line pressure control device of automatic transmission - Google Patents

Abstract

PURPOSE:To effectively restrain speed change shock in a simple structure by learning and correcting a line pressure so that speed change hours at the time of shift-up are to be a desired value in the case when a speed change mode in which a shift line is drawn aside to a low car speed. CONSTITUTION:A control unit 100 is provided with a mode selection means 103 to select either of an economy mode in which a shift line is set on the side of low car speed and a power mode in which the shift line is set on the side of high car speed and a mode detection means 104 to detect which of the modes is selected by the mode selection means 103. Additionally, the control unit 100 is provided with a control means 106 to control line pressure of a hydraulic control circuit 30 by way of controlling a duty solenoid valve 33 of a line pressure variation means and a learning and correction means 107 to learn and correct the line pressure so that speed change hours at the time of shift-up are to be a desired value correspondingly in the case when the economy mode is detected by the mode detection means 104.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a line pressure control device for an automatic transmission, and particularly to learning control of line pressure during gear shifting.

(Prior Art) Automobile automatic transmissions generally include a torque converter and a multi-stage transmission mechanism using a planetary gear mechanism, etc., and various clutches for switching the power transmission path in the transmission mechanism.
Frictional elements for speed change, such as brakes, are also provided, and these frictional elements are operated by a hydraulic control circuit.

Then, by controlling solenoid valves and the like incorporated in the hydraulic control circuit, the friction elements are engaged and opened, and the gears are changed.

The line pressure of the above-mentioned hydraulic control circuit is maintained by the oil pump and pressure regulating valve, or if the line pressure during gear shifting is too high, the friction element is suddenly engaged, causing a gear shifting shock, and if the line pressure is too low, the line pressure is too high. , the shift time becomes longer, and the friction elements become abnormally worn and generate heat.

For this reason, for example, in the device disclosed in Japanese Patent Publication No. 63-3183, the line pressure supplied to the friction element is controlled so that the engagement force of the friction element changes gradually during a gear shift, and the gear change time (shift time ) by setting a target value in advance and feedback-controlling the line pressure according to the difference between this target value and the actual shift time.
The actual shift time is adjusted so that it approaches the target value.

In addition, in general electronically controlled automatic transmissions, the gear shift patterns are determined using the throttle opening and turbine rotation (or vehicle speed) as parameters: 1st to 2nd gear, 2nd to 3rd gear, and 3rd to 4th gear. A shift-up map with shift lines showing the respective gear shifting positions, and a shift town map with shift lines showing the shifting positions from 2nd gear to 1st gear, 3rd gear to 2nd gear, and 4th gear to 3rd gear. Maps are stored in the memory within the control unit, and gears are changed based on the search for these maps.

Furthermore, there are automatic transmissions that are equipped with a plurality of the above-mentioned shift patterns, and generally, a first shift mode (economy mode) in which the shift line is set toward low vehicle speeds, and a second shift mode in which the shift line is set toward high vehicle speeds. Shift mode (power mode)
You can choose between the two.

By the way, in an automatic transmission configured to be able to select one of two shift motes, a target value of shift time is set in advance for each shift mote for various combinations of gears before and after shifting. However, it may be said that it is ideal to learn and correct the line pressure so that the actual shifting time becomes the above target value, but in reality, due to constraints due to the capacity of the on-board computer, it is necessary to correct the line pressure for both of the two shifting modes. There are cases where it is impossible or difficult to perform line pressure learning correction. In this case, if line pressure learning correction is performed only for one shift mode, there is a problem in that a shift shock that causes discomfort to the occupant occurs in the other shift mode.

(Object of the Invention) Therefore, the present invention provides a line pressure variable means capable of changing the line pressure of a hydraulic control circuit for a friction element included in a multi-stage transmission mechanism, a control means for controlling the line pressure variable means, and at least one A first shift mode in which the shift line representing the shift pattern when shifting up from one gear to the next gear is set toward low vehicle speeds, and a second shift mode in which the shift line is set toward high vehicle speeds. In a line pressure control device for an automatic transmission equipped with a mode selection means that can select between two transmission modes, the problem is solved in cases where it is impossible or difficult to perform line pressure learning correction for both of two transmission modes. An object of the present invention is to provide a line pressure control device for an automatic transmission.

(Structure of the Invention) The present invention includes a mode detection means for detecting which shift mode is selected, and a case where the mode detection means detects that a shift mode in which the shift line is set toward a low vehicle speed is selected. The present invention is characterized by comprising a learning correction means for learning and correcting the line pressure in response to this, so that the shift time at the time of upshifting becomes the target value.

(Effect of the invention) In the so-called power mode where the shift line of the shift pattern is set in a high vehicle speed range, the shift speed is high, so the inertia of the rotating part of the automatic transmission is large, and the shift time becomes longer, so this is not appropriate. Line pressure needs to be increased. Therefore, if the line pressure learning value selected by the power mode is applied to control the line pressure in a so-called economy mode in which the shift line is set toward a low vehicle speed, there is a risk that a shift shock may occur.

On the other hand, if line pressure learning correction is performed only in economy mode and this learned value is applied to line pressure control in power mode, as in the present invention,
It is possible to prevent the occurrence of gear shift shock. Further, in the present invention, since the shift time is adjusted by adjusting the line pressure, shift shock can be effectively suppressed while simplifying the structure of the control system and the like.

In addition, if the power mode is selected or when relatively rapid acceleration is detected by the sudden acceleration detection means, the power mode is not likely to be selected very often. The application of the invention becomes suitable.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of an embodiment of the present invention, and in the figure, an automatic transmission AT includes a torque converter 2, a multi-stage transmission mechanism 10, and a hydraulic control circuit 30. The multi-stage transmission mechanism 10 incorporates various friction elements (brakes, clutches) for switching power transmission paths, and a hydraulic control circuit 3o that controls engagement and release of each friction element.
It is now controlled by. Inside the hydraulic control circuit 30, there is a pressure regulator hub 32 that adjusts the line pressure that becomes the hydraulic pressure supplied to the friction elements;
Duty solenoid valve 3 that controls this
3, and these valves 32 and 33 constitute a line pressure variable mechanism.

The hydraulic control circuit 30 includes a control unit (ECU) 100 configured by a microcomputer or the like.
The control unit 100 includes a signal from a throttle opening sensor 101 that detects the opening of a throttle valve disposed in the intake passage of the engine, and a turbine rotational speed that detects the turbine rotational speed of the torque converter 2. Signals and the like from the sensor 102 are input.

As shown in FIG. 6, which will be described later, the control unit 100 sets two shift patterns, an economy mode and a power mode, in which shift lines are determined in advance using throttle opening and turbine rotational speed (or vehicle speed) as parameters. economy mode with the shift line set to the low vehicle speed side (low turbine speed side),
Mote selection means 103 for selecting one of the power modes set on the high vehicle speed side (high turbine rotation speed side)
and mode detection means 104 for detecting which mote is selected by the mode selection means.

The control unit 100 also includes a sudden acceleration detection means 105 that detects whether or not a rapid acceleration operation has been performed based on an input signal from the throttle opening sensor 101. When the power mode is detected, the mode selection means 103 selects the power mode in response.

Further, the control unit 100 includes a control means 106 that controls the line pressure of the hydraulic control circuit 30 by controlling the duty solenoid valve 33 of the line pressure variable means, and a mode detection means 104 that controls the economy mode. In response to this, the learning correction means 107 learns and corrects the line pressure so that the shift time at the time of upshifting becomes the target value.

FIG. 2 is a diagram showing an example of the configuration of an automatic transmission AT to which the device of the present invention is applied. In FIG. 2, a torque converter 2 is connected to the output shaft 1 of the engine, and a multi-stage transmission mechanism 10 is disposed on the output side of the torque converter 2. The torque converter 2 is connected to the output shaft 1 of the engine.
A pump 3 fixed to a turbine 4, a fixed shaft 7 via a one-way clutch 6 (fixed to a case 11)
and a stator 5 provided above.

The multi-stage transmission mechanism 10 includes a solid shaft 12 for driving an oil pump whose base end is connected to an oil pump 31, and a turbine 4 whose base end is a torque converter 2 outside the solid shaft 12. a hollow turbine shaft 13 connected to
A Ravigneau-type planetary gear unit 14 is provided on the turbine shaft 13. This planetary gear device 14
consists of a small-diameter sun gear 15, a large-diameter sun gear 16, a long pinion gear 17, a short pinion gear 18, and a ring gear 19, and the following various friction elements are incorporated into this planetary gear device 14.

A forward clutch 20 and a coast clutch 21 are arranged in parallel between the turbine shaft 13 and the small diameter sun gear 15 at the end farthest from the engine. The forward clutch 20 is a first one-way clutch 22
It connects and disconnects power transmission from the turbine shaft 13 to the small diameter sun gear 15 via
is for intermittent power transmission between the turbine shaft 13 and the small diameter sun gear 15.

A brake drum 23a connected to the large-diameter sun gear 16 and a brake pan l' 23 attached to the brake drum 23a are disposed radially outward of the coast clutch 21.
A 2-4 brake 23 with a
It is set to be fixed at 6. Behind the 2-4 brake 23 (on the right side of the figure), a reverse clutch 24 for backward running is disposed to connect and disconnect power transmission between the large-diameter sun gear 16 and the turbine shaft 13 via the brake drum 23a. has been done. Also, between the carrier 14a of the planetary gear unit 14 and the case 14a of the transmission gear mechanism 10 on the outside in the radial direction of the planetary gear unit 14, there is a low reverse brake 25 that engages and disengages the carrier 14a and the case 10a.
is arranged, and a second one-way clutch 26 is also arranged in parallel therewith.

Further, a 3-4 clutch 27 is disposed at the end of the planetary gear set 14 on the engine side to connect and disconnect power transmission between the carrier 14a and the turbine shaft 13. Further, an output gear 28 connected to a ring gear 19 is arranged in front of the 3-4 clutch 27 (on the left side in the figure), and this gear 28 is attached to an output shaft 28a. Note that 29 is a lock-up clutch for directly connecting the output shaft 1 of the engine and the turbine shaft 13 through the torque converter 2.

This transmission gear mechanism 10 has four forward speeds and one reverse speed.
It has several gears, and a desired gear can be obtained by appropriately operating the clutches 20, 21, 24, 27 and brakes 23, 25. Here, Table 1 shows the operational relationship between each gear stage, clutch, and brake.

FIG. 3 shows the hydraulic control circuit 3 in the automatic transmission AT.
It shows 0. This hydraulic control circuit 30 has an oil pump 31 driven by the engine output horn shaft 1, and hydraulic oil is discharged from the pump 31 into the oil path Ll. The hydraulic oil discharged from the pump 31 to the oil path L1 is guided to the pressure regulator valve 32. This pressure regulator valve 32 adjusts the oil pressure (line pressure) of hydraulic oil from the pump 31 and is controlled by a duty solenoid valve 33. That is, the hydraulic pressure of the hydraulic oil reduced to a predetermined pressure by the solenoid reducing valve 34 is applied to the duty solenoid valve 33.
The duty is controlled by In other words, the hydraulic pressure is controlled by adjusting the opening/closing time ratio of the duty solenoid valve 33 to control the drain amount, and this is given as a pilot pressure to the pressure regulator valve 32, so that the line pressure is adjusted according to this pilot pressure. is adjusted. In this way, a line pressure variable means is constructed, and as shown in FIG. 1, the line pressure is controlled by controlling the duty solenoid valve 33 by the control unit 100.

The line pressure regulated by the pressure regulator valve 32 is transferred to the manual shift valve (select valve) 3.
5 to port g. This manual shift valve 35 is manually shifted to P, R-N-D, 2, and Lunge, and hydraulic oil is supplied from port g to a predetermined port in each range. Port g communicates with port a1e when the manual shift valve 35 is set to range, and communicates with ports a and C when it is set to range 2.
When connected to port a and set to D range, port a,
b and c, and when set to R range, communicates with ports e and f.

Port a of the manual shift valve 35 is connected to the 1-2 shift valve 36 through an oil path L2. A pilot pressure controlled by a 1-2 solenoid valve 37 acts on the 1-2 shift valve 36 . In the first gear, the 1-2 solenoid valve 37 is turned off, so that the spool of the 1-2 shift valve 36 is operated, for example, to the left, and the oil passage leading to the apply chamber 23c of the 2-4 brake 23 is activated. L3 is connected to the drain side, and when the 1-2 solenoid valve 37 is turned ON in the 2nd-4th gear, the spool of the 1-2 shift valve 36 is operated, for example, to the right, and the hydraulic pressure from port a is is supplied to the apply chamber 23c of the 2-4 brake 23. Furthermore, this 1-2 shift valve 36 is adapted to supply hydraulic oil supplied from port e of the manual shift valve 35 via the low pressure reducing valve 38 to the low reverse brake 25 when the lunge is in the first gear. There is.

The oil pressure from port a of the manual shift valve 35 is 2
-3 shift valve 39 is also given as pilot pressure. This 2-3 shift valve 39 is connected to port C of the manual shift valve 35 through an oil path L4, and its pilot pressure is controlled by a 2-3 solenoid valve 40. And in 1st and 2nd gear, 2
-3 solenoid valve 40 is turned on,
The spool of the 2-3 shift valve 39 is operated, for example, to the right, and in this state, the oil passage L leading to the 3-4 clutch 27
5 is communicated with the train side, and the 3-4 clutch 27 is released. In addition, when the 2-3 solenoid valve 40 is turned off in the third and fourth speeds, the spool of the 2-3 shift valve 39 is operated, for example, to the left, and in this state, the hydraulic oil from port C is 3-4 sent to oil path L5
Clutch 27 is engaged.

The oil passage L5 is also connected to a 3-4 shift valve 41, and a pilot pressure controlled by a 3-4 solenoid valve 42 acts on this 3-4 shift valve 41. When the 3-4 solenoid valve 42 is turned on during the 1st, 2nd, and 4th speeds of the D range and the 1st speed of the 2nd range, the spool of the 3-4 shift valve 41 is moved, for example, to the right. In this state, the oil passage L leading to the release chamber 23d of the 2-4 brake 23 is activated.
6 is connected to the drain side. Also, in 3rd gear of D range,
When the 3-4 solenoid valve 42 is turned OFF during the 2nd and 3rd speeds of the 2 range and the 1st and 2nd speeds of the lunge, the spool of the 3-4 shift valve 41 is operated, for example, to the left. In this state, the oil passage L6 and the oil passage L5 connected to the 2-3 shift valve 39 are communicated, and the 2-3 shift valve 39 is connected to the oil passage L6.
-2-4 brake 2 depending on the operation of the -3 shift valve 39
Hydraulic pressure is supplied to and discharged from the release chamber 23d of No. 3. Furthermore, the 3-4 shift valve 41 switches the supply and discharge of hydraulic pressure between the oil passage L7 leading to port a of the manual shift valve 35 and the oil passage L8 leading to the coast clutch 21, thereby controlling the coast clutch 21 accordingly. There will also be a release and a contract.

In this way, in response to the operation of each shift valve 36, 39, 41 controlled by the solenoid valve 37, 40, 42, the 2-4 brake 23, which is a friction element for shifting,
(Hydraulic pressure is supplied to the apply chamber 23c, and the release chamber 23c is
d is engaged when the hydraulic pressure is drained, and otherwise released) and whether the clutch 27 is engaged or released or the first
This is done as shown in the table. In addition, each shift valve 36
．． 39. In the hydraulic circuit between 41 and 2-4 brake 23 and 3-4 clutch 27, 1-2 accumulator 43 and 2-3 accumulator 4 are installed to reduce shift shock.
4.2-3 timing valve 45.3-2 timing valve 46 and bypass valve 47 are incorporated.

In addition, the hydraulic control circuit 30 includes D.

2. Oil passage L9 that sends hydraulic pressure from port a to engage the forward clutch 20 in lunge and the N-D accumulator 48 connected to this, and hydraulic pressure from port f to engage the reverse clutch 24 in R range. Oil passage LIO that sends the oil and N-R accumulator 4 connected to this
9. A lock-up control valve 50 for controlling the lock-up clutch 29, a lock-up solenoid valve 51 for controlling the same, a converter relief valve 52, etc. are provided.

For such a hydraulic control circuit 30, the control unit 100 shown in FIG.
Prior to explaining this control operation, which is performed according to the flowcharts shown in the figures and subsequent figures, the shift mode selection routine will be explained.

FIG. 4 is a flowchart of a shift mode selection routine executed by control unit 100, and the flowchart in FIG. 4 corresponds to the rapid acceleration detection means 107 and shift mode selection means 103 in FIG.

The memory in the control unit 100 stores a shift pattern as shown in FIG. 6, which defines three shift lines for each of the economy mode and power mode, using the throttle opening degree and turbine rotation speed (or vehicle speed) as parameters. The upshift map is stored in advance, and the downshift map is shown as a solid line, which is closer to the low turbine rotation speed (that is, closer to the low vehicle speed).
■ indicates the shift positions from 1st to 2nd gear, 2nd to 3rd gear, and 3rd to 4th gear in economy mode, and the shift toward high turbine speed (that is, toward high vehicle speed) is indicated by a broken line. Down Bi, ■', and ■' respectively indicate similar shift positions in the power mode.

Note that a shift down map (not shown) is also stored in the memory within the control unit 100.

In FIG. 4, first, in step S1, the throttle opening T
VO is read from the sensor 101, and in the next step S2, a throttle opening change ΔTVO per unit time during acceleration is calculated. In step S3, it is checked whether ΔTVO is greater than or equal to the set value. If the determination is YES, the power mode is selected in step S4, and the process proceeds to step S5. Step S
If the determination in step 3 is NO, the economy mode is selected in step S6.

In the memory of the control unit 100, a map indicating a load/load line using the throttle opening degree and vehicle speed V as parameters is stored, and when the power mode is selected in step S4, the map is displayed in step S5. The upper throttle opening TVO is searched.

If the determination in step S5 is YES, that is, while the throttle opening TVO value is in region B of the map in FIG. 6, the process returns to step S4 and the power mode is maintained, or the determination in step S5 is NO. When the value of the throttle opening TVO reaches the area A shown in FIG. 5, the process proceeds to step S6 and the mode is switched to the economy mode.

Note that the determination in step S3 may be made using the map shown in FIG.

FIG. 7 shows the main routine for line pressure control executed by the control unit 100. First, it is checked in step Sll whether or not it is time to shift gears, and if the determination is NO,
In step S12, a routine for line pressure control outside of gear shifting shown in FIG. 8, which will be described later, is executed. If the determination in step S11 is YES, in step S13 a line pressure control routine during gear shifting shown in FIG. Check whether it is in mode or not.

The determinations in steps S14 and S15 are both YES.
In the case of S, as a process corresponding to the learning correction means 107 shown in FIG. 1, in step S16, a line pressure correction routine by learning the shift time shown in FIG. 14, which will be described later, is executed. Also, if the determination in step S14 is YES, step S1
If the determination in step 5 is No, that is, if the power mode is selected, a line pressure correction routine based on the economy mode learning value is executed in step S17.

The routine for line pressure control outside of gear shifting performed in step S12 in FIG. 7 is as shown in FIG. In this routine, the throttle opening and the turbine rotation speed are read from the respective sensors 101 and 102 in steps S21 and S22, and the line pressure is determined by map search according to the throttle opening and the turbine rotation speed in step S23. That is, regarding the line pressure when the gear is not shifted, values corresponding to the throttle opening degree and the turbine rotational speed are stored in advance as a map in the memory within the control unit 100, and the values are retrieved.

Next, in accordance with the line pressure determined in step S23, a duty ratio of the duty solenoid valve 33 is determined by executing a duty ratio determination routine to be described later in step S24. Further, in step S25, the solenoid drive frequency is set to, for example, 35 Hz. Next, in step S26, the ON time of the duty solenoid valve 33 in one cycle is determined by multiplying the drive cycle (reciprocal of the drive frequency) by the duty ratio, and in accordance with this, the duty solenoid valve 33 is turned on in step S27. Drive. Thereby, the line pressure is controlled to the value determined in step S23.

The line pressure control routine during gear shifting performed in step S13 in FIG. 7 is as shown in FIG. In this routine, first, in step S31, it is determined whether or not there is an upshift. When shifting up, the throttle opening is read in step S32, and the line pressure PL is determined in step S33 according to the shift mode, the gears before and after the shift, and the throttle opening. In this way, the line pressure during upshifting can be adjusted appropriately. In other words, the shock at the time of upshifting is related to the engine output and the gear position depending on the throttle opening, and in particular, the shared torque and capacity of the friction elements that are switched during gear shifting differ depending on the gear position. If the line pressure is set regardless, it is not possible to adjust the optimum speed etc. for all the gears only by setting the characteristics of the accumulator in the hydraulic control circuit 30. Therefore, in this embodiment, regarding the line pressure at the time of upshifting,
As shown in FIG. 10(a), the line pressure values according to the throttle opening degree are stored in the memory in the control unit 100 as maps for each economy mode and power mode for each combination of gears before and after shifting, The line pressure is calculated from this map. Therefore, in the past, as shown by the two-dot chain line in FIG. 10(b), a relatively high line pressure was set to the extent that all friction elements could be prevented from slipping, but in this embodiment, as shown in FIG. As shown by the solid line in b), the line pressure is set to a value that is lower than before and differs depending on the gear position.

This value is corrected and made appropriate by a routine (step 516) in FIG. 14, which will be described later.

Further, when the determination in step S31 is No, that is, when the shift is down, it is checked in step S34 whether or not the shift is down from the third gear to the second gear, and the determination is YES.
In this case, the line pressure calculation processing is performed in steps 335 to 838, and N is reached.

In this case, the process moves to line pressure control outside of gear shifting (step 512). This is done because the 3-4 clutch 27 is released when downshifting from 3rd gear to 2nd gear when using a multi-stage transmission mechanism and hydraulic control circuit as shown in Figures 2 and 3. At the same time, the 2-4 brake 23 is engaged, so adjustment of the engagement timing is required. However, during other downshifts, only the 3-4 clutch 27 or the 2-4 brake 23 is released, and the line pressure Although adjustment of the fastening timing is not required. However, the multi-stage transmission mechanism and hydraulic control circuit shown in Figures 2 and 3.
If a device with a configuration different from that shown in the diagram is used to release a specific friction element and engage other gear shifting friction elements during downshifts other than from 3rd to 2nd, this Steps 835 to S3 are also performed during gear changes such as
8 should be performed.

In the process of downshifting from third speed to second speed, the turbine rotation speed is read in step S35, and step S3
In step 6, the baseline pressure PL is determined in accordance with the turbine rotation speed. In other words, from the third speed to the second speed according to this embodiment,
When downshifting to high speed, the 3-4 clutch 27 is released to set the neutral state, and then the 2-4 brake 23 is engaged when the turbine rotation speed reaches the appropriate rotation speed, or the engagement timing depends on the turbine rotation speed. Therefore, as shown in Fig. 11, the control unit 1 uses the baseline pressure PL according to the turbine rotation speed as a map.
00, and the baseline pressure PL is determined from this map.

In step S37.838 following step S36,
The line pressure is corrected according to the throttle opening change rate calculated from multiple throttle opening detection values.In other words, as the throttle opening change rate becomes faster, the engine speed (turbine speed) increases faster. Therefore, in order to advance the engagement timing accordingly, as shown in Fig. 12, a correction coefficient Ca is determined according to the throttle opening change speed, and by multiplying this by the baseline pressure PL, the final line pressure PL is determined. demand.

Following step S33 or step 838, a duty ratio determination routine to be described later is executed in step S39, a solenoid drive frequency is set in step S40, a solenoid ON time is calculated in step S41, and a duty ratio is determined in step S42. By driving the solenoid valve 33, the duty solenoid valve 33 is controlled so that the line pressure becomes the value determined in step S33 or step S38. These steps 53
9 to S42, the duty ratio determination routine performed in step S24 in FIG. 8 and step S39 in FIG. 9 is as shown in FIG. In this routine, the line pressure is read in step S45, and the line pressure is read in step S45.
46 reads the automatic transmission oil temperature. And step S
At step 47, a base duty ratio DUo corresponding to the line pressure at the oil temperature at that time is determined. In other words, since the correspondence relationship between the duty ratio of the duty solenoid valve 33 and the line pressure changes depending on the oil temperature, step S47
As shown in the frame, the correspondence between the above-mentioned duty ratio and line pressure at multiple oil temperatures is investigated in advance and stored as a map in memory, and linear interpolation is performed between each temperature from these maps. Base duty ratio D
Find Uo. Further, during a predetermined period of time after the engine starts, the characteristics of the control pressure with respect to the duty ratio differ due to the influence of air entrainment. Therefore, in step S48, the elapsed time after the key is turned on is checked, and in step S49, the elapsed time is determined as shown in the figure. In step S50, the pace duty ratio DU is multiplied by the correction coefficient Cdu to obtain the final duty ratio DU. In this way, the duty ratio is determined so as to give the calculated line pressure.

The line pressure correction routine by learning the shift time performed in step S16 in FIG. 7 is as shown in FIG. 14. This routine corrects the line pressure stored in the memory as determined in step S33 in FIG. 9 when upshifting in economy mode, and as the friction elements are gradually engaged during upshifting. The turbine rotation speed decreases to the rotation speed after the shift, and the shift time is related to the engagement speed of the friction element, so in this embodiment, the line pressure in this case is corrected according to the shift time. . In this routine, step S
In step S51, the turbine rotation speed is read, and in step S52, the target turbine rotation speed after the shift is calculated from the turbine rotation speed before the shift. Then, in step S53, it is determined whether or not the shift is completed based on whether the conditions that the difference between the turbine rotation speed and the target turbine rotation speed is less than or equal to a predetermined value and the rate of change of the turbine rotation speed is less than or equal to a predetermined value are satisfied. Then, when it is determined that the shift has been completed, the shift time T is measured in step S54.

Subsequently, in step S55, the optimum shift time T for each shift is determined.
Calculate tag. This optimum shift time T tag is the first
The weighting coefficient Cw is multiplied by the target shift time TO set so as to obtain the appropriate turbine rotational speed change shown by the solid line in FIG. The target shift time To is stored in the memory in the control unit 100 as a map of values corresponding to the combination of gear stages before and after the shift, as shown in FIG.
The line pressure is calculated from this map. Furthermore, as shown in FIG. 17, the weighting coefficient Cw is a coefficient that takes 1 when the throttle opening is from 6/8 to 8/8 and increases as the throttle opening becomes smaller, and a, > a 4
> a 3 > a 2 > a 1. Then, in the next step S56, a shift time shift ΔT is calculated from the difference between the shift time T and the optimum shift time T tag, and in step S57, the 18th
A map search is performed for line pressure correction values set in the correspondence relationship shown in the figure. In other words, if the shift time shift ΔT is sufficiently close to zero, the line pressure correction value is set to O, or if the shift time shift ΔT is negative (as shown by the broken line in FIG. 15, the shift time T, If it is shorter), set the line pressure correction value to negative,
If the deviation ΔT is positive (if the shift time T2 is long as shown by the dashed line in FIG. 15), the line pressure correction value is made positive.

Then, in step S58, the current line pressure correction value is added to the previous line pressure learning value stored in the memory to update the learning value. Values modified in this way are used for subsequent control.

As is clear from the above description, when the line pressure control device for an automatic transmission according to the present invention performs line pressure learning correction only in one shift mode, this learning correction is performed when the shift line of the shift pattern is low. This is executed in the transmission mode (economy mode) set to 1, and this learned value is applied to control the line pressure of the transmission motor (power mode) in which the shift line is set to high vehicle connection. , it is possible to effectively suppress shift shock.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is an external circuit diagram of the structure of an automatic transmission, FIG. 3 is a block diagram of a hydraulic control circuit for the transmission mechanism, and FIG. 4 5 is a flowchart showing a gear shift mode selection routine.
Figure 6 is a characteristic diagram showing the throttle opening according to vehicle speed, Figure 6 is a shift up map, Figure 7 is a flowchart showing the main routine of line pressure control, and Figure 8 is a flowchart showing the line pressure control routine outside of shifting. , FIG. 9 is a flowchart showing the line pressure control routine during gear shifting, the first
Figures 0 (a) and (b) are a chart showing a map of line pressure during upshifting and a characteristic diagram of this line pressure, and Fig. 11 is a chart showing a map of baseline pressure during downshifting.
Fig. 2 is a characteristic diagram of the correction coefficient according to the throttle opening change rate, Fig. 13 is a flowchart showing the duty ratio determination routine, Fig. 14 is a flowchart showing the line pressure correction routine by learning the shift time, and Fig. 15. 16 is a diagram showing the change in turbine rotation speed during upshifting, FIG. 16 is a chart showing a map of shift time, FIG. 17 is a chart showing a map of weighting coefficients, and FIG. 18 is a chart showing line pressure according to shifts in shift time. It is a characteristic diagram of the correction value of. 10... Multi-stage transmission mechanism 30... Hydraulic control circuit 3
2...Pressure regulator valve 33...Duty solenoid valve 100...Control unit 103...Mode selection means 104...Mode detection means 105...Sudden acceleration detection means 106...Control means 107 ...Learning correction means 42

Claims (1)

[Scope of Claims] 1. A line pressure variable means capable of changing the line pressure of a hydraulic control circuit for a friction element included in a multi-stage transmission mechanism, a control means for controlling the line pressure variable means, and at least one transmission. Select either a first shift mode in which the shift line representing the shift pattern when shifting up from one gear to the next gear is set toward a low vehicle speed, or a second shift mode in which the shift line is set toward a high vehicle speed. a line pressure control device for an automatic transmission, comprising: a line pressure control device for an automatic transmission; If the selection of the shift mode is detected, in response to this, the line pressure is learned and corrected so that the shift time when shifting up from the at least one gear to the next gear becomes a target value. A line pressure control device for an automatic transmission, comprising a correction means. 2. Further comprising a sudden acceleration detection means for detecting whether a relatively rapid acceleration operation exceeding a preset level has been performed, and when a relatively rapid acceleration is detected by the sudden acceleration detection means, Claim 1, wherein the mode selection means selects the second shift mode in response.
Line pressure control device for the automatic transmission described.