KR20140092443A - Method of line pressure learning for continuously variable transmission and system thereof - Google Patents

Method of line pressure learning for continuously variable transmission and system thereof Download PDF

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Publication number
KR20140092443A
KR20140092443A KR1020120155386A KR20120155386A KR20140092443A KR 20140092443 A KR20140092443 A KR 20140092443A KR 1020120155386 A KR1020120155386 A KR 1020120155386A KR 20120155386 A KR20120155386 A KR 20120155386A KR 20140092443 A KR20140092443 A KR 20140092443A
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KR
South Korea
Prior art keywords
line pressure
pressure
driven pulley
learning
pulley
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KR1020120155386A
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Korean (ko)
Inventor
김세진
이호영
Original Assignee
현대자동차주식회사
기아자동차주식회사
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Priority to KR1020120155386A priority Critical patent/KR20140092443A/en
Publication of KR20140092443A publication Critical patent/KR20140092443A/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
    • F16H61/0262—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being hydraulic
    • F16H61/0265—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being hydraulic for gearshift control, e.g. control functions for performing shifting or generation of shift signals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
    • F16H59/02—Selector apparatus
    • F16H59/08—Range selector apparatus
    • F16H2059/082—Range selector apparatus with different modes
    • F16H2059/086—Adaptive mode, e.g. learning from the driver
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H2061/0075—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by a particular control method
    • F16H2061/0087—Adaptive control, e.g. the control parameters adapted by learning

Abstract

Disclose are a line pressure learning method and apparatus for a continuously variable transmission, which can accurately learn an actual line pressure when a line pressure sensor is not applied to minimize the difference between the actual line pressure and pulley pressure, thereby improving durability and fuel efficiency. According to the present invention, the line pressure learning method for a continuously variable transmission which comprises a driving pulley and a driven pulley and delivers power by connecting the pulleys using a belt comprises the steps of: entering line pressure learning mode when a shift lever selects a P or N gear stage; actuating a solenoid valve for line pressure control to the maximum to supply the maximum line pressure to the driven pulley, and measuring the pressure of the driven pulley corresponding to line pressure by using a driven pulley pressure sensor; detecting the deviation between the pressure of the driven pulley and target line pressure to compensate for line pressure control current; and storing the line pressure control current as a learning value when the pressure of the driven pulley converge on the target line pressure and the convergence is maintained for a predetermined time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a line pressure learning method and apparatus for a continuously variable transmission,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission, and more particularly, to a continuously variable transmission which is capable of providing a durability and an improvement in fuel economy by minimizing the difference between the actual line pressure and the pulley pressure, Line pressure learning method and apparatus.

The continuously variable transmission is a transmission that implements the transmission ratio by varying the diameter according to the driven pulley pressure input to the driven pulley and the drive pulley pressure input to the drive pulley and transmits power between the drive pulley and the driven pulley through friction of the belt.

The continuously variable transmission uses a line pressure (or a pump pressure) as a source pressure of a driven pulley pressure and a drive pulley pressure, and controls a line pressure by combining a solenoid valve or a spool valve.

At this time, if the line pressure controlled by the combination of the solenoid valve or the spool valve is not accurately controlled, durability and fuel economy are adversely affected.

For example, when the actual line pressure is lower than the target line pressure and the line pressure is insufficient, the pulley pressure using the line pressure as the source pressure becomes insufficient. As a result, the slip of the belt and the pulley is severely generated, resulting in a durability problem.

In addition, the transmission ratio control becomes inaccurate due to insufficient pulley pressure, which may cause a problem that the drivability is deteriorated.

Also, owing to lack of source pressure during pulley pressure learning, erroneous learning may occur.

On the contrary, when the line pressure is higher than the target, a load is given to the engine or the motor that drives the oil pump, so that the fuel consumption deterioration can be caused.

Therefore, the line pressure must be higher than the pulley pressure at all times. Therefore, the line pressure is controlled by adding a margin to the required pulley pressure. If there is no line pressure sensor, the margins must be increased in consideration of the deterioration due to the deviation between individual items and durability. Lt; / RTI >

Patent Registration No. 10-0307743 (Aug. 23, 2001) Published Patent Application No. 10-2007-0119764 (December 21, 2007)

An object of the present invention is to provide a continuously variable transmission that improves durability and fuel economy by minimizing the difference between the line pressure and the pulley pressure by accurately learning the line pressure only with the pulley pressure sensor without applying the line pressure sensor, A line-pressure learning method and an apparatus.

According to an embodiment of the present invention, there is provided a line pressure learning method of a continuously variable transmission that is constituted by a drive pulley and a driven pulley and is connected to a belt and transmits power, wherein when the shift lever selects the P- Mode; A process of operating the line pressure control solenoid valve to the maximum to supply the maximum line pressure to the driven pulley and measuring the pressure of the driven pulley corresponding to the line pressure by the driven pulley pressure sensor; A process of correcting the line pressure control current by detecting a deviation of the pressure of the driven pulley and the target line pressure; And storing the line pressure control current as a learning value when the pressure of the driven pulley and the target line pressure converge and remain constant for a predetermined time.

The line pressure control current learning can repeatedly learn more than the set number by gradually changing the target line pressure.

As described above, the present invention can accurately measure the actual line pressure without applying the Gauges in the continuously variable transmission, thereby providing durability and fuel economy improvement, and cost reduction, thereby improving price competitiveness.

1 is a view schematically showing a line pressure learning apparatus of a continuously variable transmission according to an embodiment of the present invention.
2 is a flowchart illustrating a line pressure learning procedure of a continuously variable transmission according to an embodiment of the present invention.
FIG. 3 is a diagram showing a line pressure learning timing for each level of the endless room according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are given the same reference numerals throughout the specification.

In addition, since the components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

1 is a view schematically showing a line pressure learning apparatus of a continuously variable transmission according to an embodiment of the present invention.

1, the line pressure learning apparatus for a continuously variable transmission according to the present invention includes an engine 10 as a power source, a torque converter (not shown) connected to an output shaft of the engine 10 and providing power transmission through a fluid coupling A first reduction gear 30 connected to the output shaft of the torque converter 20 to reduce the output revolution number of the torque converter 20 at a predetermined ratio, a second reduction gear 30 connected to the output shaft of the first reduction gear 30, A secondary transmission 50 provided in series with the output end of the variator 40 and a second secondary transmission 50 which decelerates the output of the secondary transmission 50 by a predetermined ratio, A control unit 80 for controlling the gear stages of the variator 40 and the auxiliary transmission 50 by analyzing the operation information and the variator 40 and the auxiliary transmission 50 according to the control of the control unit 80. [ And a hydraulic drive unit 90 for performing engagement of the gears of the drive wheels.

When the solenoid valve and the spool valve are combined, the hydraulic pressure from the oil pump 91, which is operated by the power of the engine 10 under the control of the control unit 80, 40 and the auxiliary transmission 50 in the gear position.

The series connection of the variator 40 and the auxiliary transmission 50 means a series connection from the engine 10 to the drive wheel via the second reducer 60 to the power transmission path.

The series connection of the variator 40 and the auxiliary transmission 50 may be integrated at the output of the variator 40 or may be connected via another power transmission mechanism.

The variator 40 includes a drive pulley 41 to which the power of the engine 10 is input via the first reduction gear 30, a driven pulley 42 connected to the input shaft of the auxiliary transmission 40, a drive pulley 41 And a belt 43 that is wound between the driven pulley 42 and the driven pulley 42 to transmit the power input to the driven pulley 41 to the driven pulley 42.

The drive pulley and the driven pulleys (21, 22) are provided on the back surface of the movable conical plate, the movable conical plate being opposed to the fixed conical plate and the fixed conical plate to form a V-groove between the fixed conical plates And pulley control valves 44a and 44b for displacing the movable conical plate in the axial direction.

The pulley control valves 44a and 44b change the width of the V-groove formed in the movable conical plate by the line pressure supplied from the hydraulic pressure drive unit 90 and rotate the belt 43, the drive pulley 41 and the driven pulley 42 So that the speed ratio of the variator 40 can be changed steplessly.

The auxiliary transmission 50 may have a gear ratio of the forward two-speed reverse gear stage.

The auxiliary transmission 50 is constituted by a planetary gear 51 that connects two planetary gear carriers and a friction element that is connected to the rotation element of the planetary gear 51 and changes the gear ratio.

The friction element may comprise a first brake 52, a clutch 53, and a second brake 54.

The gear position of the auxiliary transmission 50 can be changed by adjusting the oil pressure supplied to the first brake 52, the clutch 53, and the second brake 54, which are the friction elements, to change the engagement or disengagement state.

For example, when the first brake 52 is engaged and the clutch 53 and the second brake 54 are released, the auxiliary transmission 50 is engaged with the first-speed gear stage, the clutch 53 is engaged, When the brake (52) and the second brake (54) are released, the auxiliary transmission (50) is coupled to the second speed gear stage having a lower speed ratio than the first speed gear stage.

When the second brake 54 is engaged and the first brake 52 and the clutch 53 are disengaged, the reverse gear of the auxiliary transmission 50 is engaged.

It can be expressed as a low speed mode when the auxiliary transmission 50 is engaged with the first speed gear and when it is engaged with the second speed gear.

The control unit 80 determines the speed ratio of the variator 40 and the auxiliary transmission 50 according to the vehicle speed VSP and the speed Npri of the drive pulley 41 by applying the shift map stored in the memory means, Thereby controlling the shift.

Since the pulley pressure can not be lowered as desired during the running, the control unit 80 enters the line pressure measuring mode at the N-stage, which is the P-stage or the neutral speed-change stage where the shift position is selected by the shift lever 74.

The control unit 80 uses the pressure sensor of the driven pulley 42 to perform the line pressure learning so that the driven pulley control valve 44b is opened to the maximum at the maximum pressure of the driven pulley 42, 90 or the line pressure control solenoid valve (or spool valve) in the line pressure control valve 90 to a maximum control current to supply the line pressure to the driven pulley 42.

At this time, the pressure of the driven pulley 42 is detected by the pressure sensor and measured at a pressure corresponding to the line pressure of the driven pulley 42 when the line pressure is not the maximum.

Therefore, when the control current of the line pressure control solenoid valve is adjusted while the driven pulley control valve 44b is maximally opened utilizing such a phenomenon, the line pressure can be measured by the driven pulley pressure sensor.

The control unit 80 performs the learning of the line pressure while raising the pressure level (for example, 10 bar, 20 bar, 30 bar) while gradually setting the target of the line pressure in the state where the shift lever 74 is positioned at the P- .

At this time, the solenoid valve for line pressure control is controlled so that the maximum line pressure is supplied to the driven pulley 42 by opening the driven pulley control valve 44b to the maximum, and the actual line pressure and the target line pressure And performs learning to correct the line-pressure control current according to the difference.

When the driving pressure is high during learning of the line pressure, the controller 80 changes the speed ratio, so that the driving pressure is varied according to the line pressure level so that the constant speed ratio is maintained.

The control unit 80 may set the relation of the solenoid valve (or the spool valve control current), which is the line pressure control current to the input line pressure, as shown in Table 1, for example.

Target line pressure (bar) 10 20 30 Line-pressure control current (mA) 700 500 300

Since the values are a minimum value (representative value) set in the control unit 80 as the shift control unit and vary slightly depending on the characteristics of the continuously installed continuously variable transmission, the line pressure control current for the target line pressure 10 bar is 700 mA When applied, 9.5 bar can be obtained.

Therefore, when the line-pressure learning is performed, the characteristic value can be changed as shown in Table 2 below, and accurate learning can be controlled by storing it as learning value.

Target line pressure (bar) 10 20 30 Line-pressure control current (mA) 680 515 322

The solenoid valve (or spool valve) is operated by the control of the control unit 80 so that the hydraulic pressure generated from the oil pump 91 is transmitted to the friction elements 40 of the variator 40 and the auxiliary transmission 50, As a line pressure.

The operation of the shift control in the control device of the continuously variable transmission according to the embodiment of the present invention including the functions described above is executed as follows.

When the shift lever 74 of the continuously variable transmission to which the present invention is applied selects the N-stage which is the P-stage or neutral shift stage that is the parking speed change stage (S101), the control unit 80 uses the pressure sensor of the driven pulley 42 Enters the line-pressure learning mode (S102).

The controller 80 enters the line pressure learning mode, and then learns the level of the line pressure by increasing the pressure level step by step (for example, 10 bar, 20 bar, 30 bar) (S103).

The control unit 80 activates the line pressure control solenoid valve in the understanding hydraulic drive unit 90 to supply the maximum line pressure to the driven pulley 42 at the maximum current control value (S104) (Step S105).

The pressure of the driven pulley 42 is detected by the driven pulley pressure sensor in a state where the driven pulley control valve 44b is fully opened as described above. When the line pressure is not the maximum, the line pressure of the driven pulley 42 Measured at the appropriate pressure.

Therefore, the control unit 80 determines whether the pressure of the driven pulley 42 is measured by the pressure sensor and converges to the line pressure in a state where the driven pulley control valve 44b is opened to the maximum (S106).

That is, when the pressure of the target line pressure-driven pulley converges to the line pressure and is maintained for a predetermined time, it is determined as the convergence of the driven pulley pressure and the line pressure and is stored as the learning value.

If the pressure of the driven pulley 42 and the line pressure do not converge at S106, the control unit 80 corrects the control current of the line pressure control solenoid valve so that the pressure and the line pressure of the driven pulley 42 can be converged S107).

That is, when a deviation is generated in the pressure of the driven pulley 42 measured against the target line pressure, the correction map is used to change the control current of the line pressure control solenoid valve to correct the target line pressure to approximate the target line pressure.

When the pressure of the driven pulley 42 and the line pressure are converged in S106, the controller 80 stores the learned value as a learning value for the set level learning interval (S108).

That is, the control unit 80 opens the driven pulley control valve 44b to the maximum and controls the driven pulley 42 to be supplied with the maximum pressure, and the actual line pressure measured by the pressure sensor of the driven pulley 42, Corrects the difference between the line pressure and the line pressure, and stores it as a learned value of the line pressure.

Also, since the control unit 80 changes the speed ratio when the driving pressure is high during the learning of the line pressure, the control unit 80 changes the driving pressure according to the line pressure level to maintain a constant speed ratio.

Then, the control unit 80 determines whether the line-pressure learning to the final-level learning interval is completed (S109). If the line-pressure learning until the last-level learning interval is not completed, the control unit 80 sets the next- And the above procedure is repeated (S110).

3, when the shift lever 74 is positioned at the P-stage or N-stage, the control unit 80 enters the line pressure learning mode, and controls the line pressure control solenoid valve so that the line pressure is transmitted to the driven pulley And corrects the control current C1 of the line pressure control solenoid valve in accordance with the deviation of the target line pressure A1, A2, A3 from the pressure pulses B1, B2, B3 of the driven pulley detected from the pressure sensor of the driven pulley. L2, and L3 so that the pressures B1, B2, and B3 of the driven pulley and the target line pressures A1, A2, and A3 converge.

Therefore, the control unit 80 calculates the target line pressure A1, A2 (A2, A2) by correcting the control current C1 of the line pressure control solenoid valve without applying the line pressure sensor, , A3) learns convergence and utilizes the learning value for line pressure control.

As shown in FIG. 3, the line-pressure learning is performed while gradually increasing the pressure level (for example, 10 bar, 20 bar, 30 bar) by the target of the line pressure step by step.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

10: engine 20: torque converter
30: first speed reducer 40: variator
50: auxiliary transmission 80:
90: Hydraulic drive

Claims (4)

A line pressure learning method for a continuously variable transmission, comprising a drive pulley and a driven pulley, connected by a belt and transmitting power,
A step of entering the line pressure learning mode when the shift lever selects the P-stage or N-stage;
A process of operating the line pressure control solenoid valve to the maximum to supply the maximum line pressure to the driven pulley and measuring the pressure of the driven pulley corresponding to the line pressure by the driven pulley pressure sensor;
A process of correcting the line pressure control current by detecting a deviation of the pressure of the driven pulley and the target line pressure;
Storing the line pressure control current as a learning value when the pressure of the driven pulley and the target line pressure converge and remain constant for a predetermined time;
Wherein the line pressure learning method of the continuously variable transmission includes: The method according to claim 1,
Wherein said line pressure control current learning is a step of varying a target line pressure step by step and learning it repeatedly for a predetermined number of times or more. The method according to claim 1,
And correcting the line pressure control current by applying a set correction map when a deviation occurs between the pressure of the driven pulley and the target line pressure. In the continuously variable transmission,
A drive pulley to which power of the engine is connected;
A driven pulley connected to the output shaft;
A control unit for controlling the speed ratio by controlling the hydraulic pressure supplied to the drive pulley and the driven pulley;
/ RTI >
Wherein the control unit is operated in accordance with a set program to execute a method according to any one of claims 1 to 3 to learn a control current for supplying line pressure to the driven pulley.
KR1020120155386A 2012-12-27 2012-12-27 Method of line pressure learning for continuously variable transmission and system thereof KR20140092443A (en)

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KR1020120155386A KR20140092443A (en) 2012-12-27 2012-12-27 Method of line pressure learning for continuously variable transmission and system thereof

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KR1020120155386A KR20140092443A (en) 2012-12-27 2012-12-27 Method of line pressure learning for continuously variable transmission and system thereof

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