KR20140092442A - Method of pully pressure learning for continuously variable transmission and system thereof - Google Patents

Abstract

Disclosed is a pulley learning method for a continuously variable transmission, which is capable of accurately learning a control current for pulley pressure following a target shift ratio and target pressure by applying a pressure sensor to only one of a driving pulley or a driven pulley. The pulley learning method of the present invention comprises the steps of: entering pulley learning mode at a P or N gear stage and setting a target shift ratio, and target pressure of a driven pulley; outputting a driving pulley control current and a driven pulley control current following the target shift ratio and the pressure of the driven pulley to supply oil pressure to the driving pulley and the driven pulley, and performing shifting; detecting shift speed, an actual shift ratio, and oil pressure supplied to the driven pulley and determining whether the detected values converge on set target values; compensating for the control current of the driving pulley and the driven pulley as much as variation when any of the shift speed, the actual shift ratio, and the oil pressure supplied to the driven pulley does not converge on the set target values; and storing the control current of the driving pulley and the driven pulley as learning values when all of the shift speed, the actual shift ratio, and the oil pressure supplied to the driven pulley converge on the target values.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pulley-

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 that applies a pressure sensor to only one of a drive pulley and a driven pulley to accurately learn a pulley pressure control current that follows a target transmission ratio and a target pressure Pulley 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 hydraulic pressure supplied to change the diameter of the drive pulley and the driven pulley to provide a speed ratio in the continuously variable transmission is supplied by the operation of the solenoid valve and the spool valve.

However, since the solenoid valve and the spool valve have a deviation from each other, there is a difference between the actual pressure and the target pressure supplied to the drive pulley and the driven pulley for each vehicle actually produced.

Therefore, when the actual pressure supplied to the drive pulley and the driven pulley is lower than the target pressure, slippage may occur between the belt and the pulley, resulting in a durability result.

On the other hand, when the actual pressure supplied to the drive pulley and the driven pulley is higher than the target pressure, the fuel efficiency may deteriorate due to the reduction of the power transmission efficiency.

Therefore, the continuously variable transmission must be controlled with the actual pressure supplied to the drive pulley and the driven pulley always to the pressure at which the target pressure converges, so that durability and fuel economy can be optimized at the same time.

There is provided a method of performing feedback control by applying a pressure sensor to each of a drive pulley and a driven pulley in order to make the actual pulley pressure equal to the target pulley pressure by a method corresponding to the pressure deviation applied to the conventional continuously variable transmission.

However, when a pressure sensor is applied to each of the drive pulley and the driven pulley, a cost increase may be caused to deteriorate price competitiveness.

Further, the reactivity is lowered by the feedback control, and the transmission feeling can be deteriorated.

Open Patent Publication No. 10-2008-0063260 (2006.06.06.) Japanese Patent Application Laid-Open No. 2007-292245 (November 8, 2007)

SUMMARY OF THE INVENTION The present invention has been developed in order to solve such a problem, and an object of the present invention is to provide a control apparatus for an automatic transmission, which is capable of accurately learning a control current of a pulley pressure that follows a target transmission ratio and a target pressure by applying a pressure sensor to only one of a drive pulley and a driven pulley And to provide a pulley pressure learning method and apparatus of a transmission.

A pulley pressure learning method of a continuously variable transmission in which a drive pulley and a driven pulley are connected to each other by a belt to transmit power, the pulley pressure learning method comprising the steps of: A target pressure setting unit for setting a target pressure of the fuel cell; Outputting a drive pulley control current and a driven pulley control current that follow a target transmission gear ratio and a driven pulley pressure to supply hydraulic pressure to a drive pulley and a driven pulley and executing a shift; Determining whether the transmission speed, the actual transmission ratio, and the hydraulic pressure supplied to the driven pulley are detected and converged to a set target value; Correcting the control currents of the drive pulley and the driven pulley by a deviation if either the shift speed, the actual speed ratio, and the oil pressure supplied to the driven pulley do not converge to a set target value; And storing the control currents of the drive pulley and the driven pulley as learning values when the transmission speed, the actual transmission ratio, and the hydraulic pressure supplied to the driven pulley converge to the target value.

The hydraulic pressure supplied to the driven pulley is converged to the target pressure set by the control current correction of the drive pulley and the driven pulley, the actual transmission ratio converges to the set target transmission ratio, and the actual transmission speed is set to a state The control current of the drive pulley and the driven pulley can be stored as learning values.

The control current learning of the drive pulley and the driven pulley can be repeatedly learned by increasing the target speed ratio and the target pressure of the driven pulley step by step.

It is possible to apply a pressure sensor only to either the drive pulley or the driven pulley so as to learn a control current that provides the pulley pressure.

When the deviation between the actual pressure measured by the driven pulley and the set target pressure is generated, the control current of the driven pulley can be corrected by applying the set correction map.

When a deviation occurs between the actual transmission ratio and the set target transmission ratio, the control current of the drive pulley can be corrected by applying the set correction map.

As described above, according to the present invention, the pressure sensor is applied to only one of the drive pulley and the driven pulley in the continuously variable transmission to accurately learn the pressure and control current supplied to the pulley, thereby improving the durability and fuel economy of the continuously variable transmission, Thereby improving price competitiveness.

1 is a view schematically showing a pulley learning apparatus of a continuously variable transmission according to an embodiment of the present invention.
2 is a flowchart illustrating a pulley learning procedure of a continuously variable transmission according to an embodiment of the present invention.
3 is a diagram illustrating a step-by-step learning procedure of the continuously variable transmission 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 pulley pressure learning apparatus of a continuously variable transmission according to an embodiment of the present invention.

1, a pulley learning apparatus for a continuously variable transmission according to an embodiment of the present invention includes an engine 10 as a power source, a torque converter 20 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 for reducing the output revolution speed of the torque converter 20 at a predetermined ratio, and a second reduction gear 30 connected to the output shaft of the first reduction gear 30, A variator 40 which is a belt type continuously variable transmission mechanism in which a transmission ratio is adjusted in accordance with the speed ratio of the transmission 40, a secondary transmission 50 which is provided in series with the output end of the variator 40, A control unit 80 for controlling the gear positions of the variator 40 and the auxiliary transmission 50 by analyzing the driving information and the variator 40 and the auxiliary transmission 50 under the control of the control unit 80. [ And a hydraulic drive unit 90 for performing engagement of the gear stages of the hydraulic pump.

The hydraulic drive unit 90 is operated under the control of the control unit 80 to supply the hydraulic pressure to the variator 40 and the auxiliary transmission 50 to set the speed ratio when the solenoid valve and the spool valve are combined.

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 21 and the driven pulley 22 are driven by hydraulic cylinders 44a and 44b that change the direct coupling between the drive pulley 21 and the driven pulley 22 in accordance with the hydraulic pressure supplied from the hydraulic drive unit 90, .

The hydraulic cylinders 44a and 44b change the width of the V-groove formed in the movable conical plate by the hydraulic pressure supplied from the hydraulic pressure drive unit 90 so as to change the width of the belt 43, the drive pulley 41, and the driven pulley 42 By changing the contact radius, 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 first reduction gear 30 may be omitted and the output of the torque converter 20 may be directly connected to the variator 40 according to the design of the continuously variable transmission.

It is also possible to eliminate the auxiliary transmission 50 and directly connect the output of the driven pulley 42 of the variator 40 to the second reducer 60. [

The control unit 80 applies the shift map stored in the memory means to the variator 40 and the auxiliary transmission (not shown) according to the speed change stage selected by the shift lever 74, the vehicle speed VSP, and the speed Npri of the drive pulley 41 50) and controls the shift through hydraulic drive.

Since the control unit 80 can not lower the pulley pressure as desired during traveling, the shift stage selected by the shift lever 74 enters the pulley pressure measurement mode at the N-stage, which is the P-stage or neutral shift stage, which is the parking speed change stage.

For example, when the pressure sensor is applied to only the driven pulley 42 without applying a pressure sensor to the drive pulley 41, the control unit 80 controls the driven pulley 42 to be driven by the driven pulley 42, 42 is not converged to the target pressure set under the condition of the speed ratio, the control current for controlling the pressure of the driven pulley 42 is compensated to compensate for the pressure deviation.

The control unit 80 corrects the pressure supplied to the driven pulley 42 via the hydraulic drive unit 90 with the corrected control current and determines the actual pressure detected by the pressure sensor applied to the driven pulley 42 and the speed ratio And the control current of the driven pulley 42 at the time point at which the target pressure is converged.

The control unit 80 learns the pressure of the driven pulley 42 while raising the target pressure of the driven pulley 42 in steps P and N, for example, 10 bar, 20 bar, and 30 bar, Learning is performed while raising the target pressure of the driven pulley 41 to stepwise, for example, 5 bar, 13 bar, and 21 bar, and learning is performed by controlling the speed ratio between the drive pulley 41 and the driven pulley 42 to be consistent.

The control unit 80 controls the drive pulley 42 such that the pressure of the drive pulley 42 corresponding to the pressure of the stepped pulley 41 is transmitted to the driven pulley 42 for maintaining the transmission ratio determined in the parking (P stage) or neutral (N stage) ) Is a value obtained by experimentally determining the ratio of the target pressure of the drive pulley 41 to the target pressure of the drive pulley 41.

For example, assuming that the transmission ratio is 1.9 at the P-stage, the transmission ratio will be changed in accordance with the pressure of the drive pulley 41 when the pressure of 10 bar is applied to the driven pulley 42 at the P-stage.

If the pressure of the driven pulley 42 is adjusted to maintain the speed ratio 1.9 and the pressure is measured at 5 bar, it is possible to maintain the speed ratio 1.9 when the pressure of the driven pulley 42 is 10 bar in the neutral state of the transmission It can be concluded that the pressure of the drive pulley 41 is 5 bar.

Therefore, even if the pressure sensor is not applied to the drive pulley 41 using this phenomenon, the pressure (10 bar) of the driven pulley 42, which is constantly converged by applying the above-described rule, It can be seen that the pressure of the drive pulley 41 is 5 bar.

When the pressure of the driven pulley 42 is applied in steps of 10 bar, 20 bar, and 30 bar in order to learn the entire controllable pressure range, the pressure of the drive pulley 41 for making the speed ratio 1.9 is 5 bar, 13 bar, The pressure of the drive pulley 41 can be learned based on this.

This is summarized in Table 1 below.

Transmission ratio 1.9 1.9 1.9 Driven pulley pressure 10 20 30 Drive pulley pressure 5 13 21

The solenoid valve and the spool valve are operated according to the control current of the control unit 80 to supply the hydraulic cylinder 44a of the drive pulley 41 and the hydraulic cylinder 44bb of the driven pulley 42 So that the hydraulic pressure corresponding to the speed ratio can be formed.

The pulley pressure learning of the continuously variable transmission according to the embodiment of the present invention including the functions described above is executed as follows.

The present embodiment will be described on the assumption that the hydraulic pressure sensor is not applied to the drive pulley 41 but the hydraulic pressure sensor is applied only to the driven pulley 42. [

When the shift lever 74 of the continuously variable transmission to which the present invention is applied selects the parking speed change stage (P stage) or the neutral speed change stage (N stage) (S101) (Step S102).

The control unit 80 determines the target speed ratio for learning after entering the pulley pressure learning mode and determines the target pressure of the driven pulley 42 (S103).

The control unit 80 then outputs the control current of the drive pulley 41 to follow the target speed change ratio so that the hydraulic pressure is supplied to the drive pulley 41 by the operation of the hydraulic drive unit 90, And the hydraulic pressure is supplied to the driven pulley 42 by the operation of the hydraulic drive unit 90 (S104).

Thus, the diameter change of the drive pulley 41 and the driven pulley 42 is performed, and the shift progresses in accordance with the target speed change ratio.

At this time, the control unit 80 detects the actual speed ratio and the hydraulic pressure supplied to the driven pulley 42 in accordance with the target speed ratio (S105). Then, the hydraulic pressure supplied to the driven pulley 42 converges to the set target pressure , The actual transmission ratio converges to the target transmission ratio set in S106, and it is determined whether the actual transmission speed is maintained for a predetermined time set to converge to the set target transmission speed (S106).

If the convergence condition is not satisfied in any one of 106, the control current of the drive pulley 41 and the control current of the driven pulley 42 are corrected according to the deviation to converge the target pressure, the target speed change ratio, (S107).

That is, when a deviation occurs between the actual pressure detected by the driven pulley 42 and the target pressure, the control current of the driven pulley 42 is corrected using the correction map, To be able to converge to pressure.

Further, when a deviation occurs in the set target speed change ratio and the actual speed change ratio or a deviation occurs in the target shift speed and the target shift speed, the control current of the drive pulley 42 is corrected using the correction map, So as to converge to the target transmission ratio and the transmission speed.

The hydraulic pressure supplied to the driven pulley 42 is converged to the set target pressure through the correction of the control currents of the drive pulley 41 and the driven pulley 42 according to the above procedure and the actual speed change ratio converges on the set target speed change ratio, The control currents of the drive pulley 41 and the driven pulley 42 are stored as learning values when the shift speed is maintained for a predetermined time set in a state of converging the set target shift speed (S108).

The control unit 80 learns the pressure of the driven pulley 42 while raising the target pressure of the driven pulley 42 to stepwise, for example, 10 bar, 20 bar, and 30 bar, For example, 5 bar, 13 bar, and 21 bar, so that the learning is performed by controlling the speed ratio between the drive pulley 41 and the driven pulley 42 to be equal to each other.

The control unit 80 determines whether the stepwise learning for learning the target pressure step by step is complete (S109). If the stepwise learning is not completed, the control unit 80 increments the learning step (S110) The target pressure and the target transmission ratio are determined, and the above-described procedure is repeatedly executed.

When the step-by-step learning is completed in step S109, the controller 80 stores the pulley pressure control learning value and applies the learning value to the next pulley pressure control (S111).

Therefore, the pressure value of the drive pulley 41 can be learned by the correction using the information detected by the pressure sensor applied to the driven pulley 42 without applying the pressure sensor to the drive pulley 41, To improve durability and shift response, and to provide fuel economy improvement.

For example, assuming that the speed ratio is 1.9 in the P-stage, the speed ratio is changed according to the pressure of the driving pulley 41 when the pressure of 10 bar is applied to the driven pulley 42 at the P- ) To maintain the transmission ratio of 1.9, and if the pressure is measured at 5 bar, the driving pulley 41 (which can maintain the transmission ratio 1.9 when the pressure of the driven pulley 42 is 10 bar in the neutral state of the transmission ) Can be concluded to be 5 bar.

Therefore, even if the pressure sensor is not applied to the drive pulley 41 using this phenomenon, the pressure (10 bar) of the driven pulley 42, which is constantly converged by applying the above-described rule, It can be seen that the pressure of the drive pulley 41 is 5 bar.

When the pressure of the driven pulley 42 is applied in steps of 10 bar, 20 bar, and 30 bar in order to learn the entire controllable pressure range, the pressure of the drive pulley 41 for making the speed ratio 1.9 is 5 bar, 13 bar, The pressure of the drive pulley 41 can be learned based on this.

These are summarized in Table 2 below.

Transmission ratio 1.9 1.9 1.9 Follower pulley pressure (bar) 10 20 30 Drive pulley pressure (bar) 5 13 21

For example, it is assumed that the control current according to each pulley pressure set to the initial value in the controller 80 is as shown in Table 3 below.

Follower pulley pressure (bar) 10 20 30 Driven pulley control current (mA) 700 500 300 Drive pulley pressure (bar) 5 13 21 Driving pulley control current (mA) 800 640 480

However, since the solenoid valve and the spool valve mounted on the continuously variable transmission can be formed differently in pressure due to the deviation between the individual parts, and the control current according to the solenoid valve and the spool valve can be formed differently, the values learned through the above- Can be summarized as shown in Table 4 below.

Follower pulley pressure (bar) 10 20 30 Driven pulley control current (mA) 680 515 322 Drive pulley pressure (bar) 5 13 21 Driving pulley control current (mA) 815 625 460

3 is a diagram illustrating a step-by-step learning procedure of the continuously variable transmission according to the embodiment of the present invention.

3, the target pressure A11 of the driven pulley and the target speed ratio B11 are set in the state that the shift stage of the shift lever is selected as the P-stage or N-stage, and then the control current of the drive pulley and the control current And executes the shift.

 Then, the actual pressure A12 supplied to the driven pulley is detected by the pressure sensor applied to the driven pulley, and the deviation [Delta] 11 between the target pressure A11 and the actual pressure A12 is measured.

When the target pressure A11 and the actual pressure A12 measured in the above are not converged and the deviation [Delta] 11 is generated, the control map of the driven pulley is corrected so that the deviation [Delta] 11 is not generated by applying the set correction map .

When the target shift ratio B11 and the actual transmission gear ratio B12 are not converged and the deviation? 12 is generated, the target shift ratio B11 and the actual transmission ratio B12 are detected to measure the deviation? The map is applied to correct the control current of the drive pulley so that the deviation [Delta] 12 is not generated.

As described above, when the target pressure A11 and the actual pressure A12 are converged (L11) by the correction of the drive pulley control current and the driven pulley control current, and the target speed ratio B11 and the actual speed ratio B12 converge ) It can be determined that the actual pressure D12 supplied to the drive pulley converges on the target pressure D11, and stores it as a learning value.

Therefore, the pressure of the drive pulley can be learned without applying the pressure sensor to the drive pulley.

The above procedure repeatedly learns for a set number of times by gradually raising the pressure of the drive pulley and the pressure of the driven pulley.

For example, the control current of the drive pulley can be learned by raising the pressure of the driven pulley to 10 bar, 20 bar, 30 bar, and the control current of the driven pulley can be learned by raising the pressure of the drive pulley to 5 bar, 13 bar and 21 bar.

The procedure for learning the control current including the drive pulley 41 to which the pressure sensor is not applied by applying the pressure sensor only to the driven pulley 42 without applying the pressure sensor to the drive pulley 41 has been described .

However, the present invention is not limited to this, and a pressure sensor may be applied to only the drive pulley 42 without applying a pressure sensor to the driven pulley 41, Is performed in the same manner, and a detailed description thereof will be omitted.

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 (7)

A pulley pressure learning method of a continuously variable transmission in which a drive pulley and a driven pulley are connected with a belt to transmit power,
A step of entering the pulley learning mode at the P-stage or N-stage to set the target transmission ratio and the target pressure of the driven pulley;
Outputting a drive pulley control current and a driven pulley control current that follow a target transmission gear ratio and a driven pulley pressure to supply hydraulic pressure to a drive pulley and a driven pulley and executing a shift;
Determining whether the transmission speed, the actual transmission ratio, and the hydraulic pressure supplied to the driven pulley are detected and converged to a set target value;
Correcting the control currents of the drive pulley and the driven pulley by a deviation if either the shift speed, the actual speed ratio, and the oil pressure supplied to the driven pulley do not converge to a set target value;
Storing the control currents of the drive pulley and the driven pulley as learning values when both the shift speed, the actual speed ratio, and the hydraulic pressure supplied to the driven pulley converge to a target value;
Wherein the pulley is a pulley. The method according to claim 1,
The hydraulic pressure supplied to the driven pulley is converged to the set target pressure by the control current correction of the drive pulley and the driven pulley, the actual speed change ratio converges to the set target speed change ratio, and the actual change speed is set to a state And the control current of the drive pulley and the driven pulley is stored as learning values when the time is maintained. The method according to claim 1,
Wherein the control current learning of the drive pulley and the driven pulley is repeatedly learned by increasing the target speed ratio and the target pressure of the driven pulley by a predetermined number of times. The method according to claim 1,
Wherein a control current is applied to either the drive pulley or the driven pulley to learn a control current to provide a pulley pressure. The method according to claim 1,
And correcting the control current of the driven pulley by applying a set correction map when a deviation occurs between the actual pressure measured by the driven pulley and the set target pressure. The method according to claim 1,
And correcting the control current of the drive pulley by applying a set correction map when a deviation occurs between the actual transmission ratio and the set target transmission ratio. 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 the method of any one of claims 1 to 6 to learn a control current to provide pulley pressure to the drive pulley and the driven pulley.

Images