KR102371746B1 - Pulley controlling hydraulic pressure calibration method and device of CVT - Google Patents

Abstract

Disclosed are a method and an apparatus for correcting a pulley control pressure of a continuously variable transmission (CVT) in which a transmission ratio continuously changes in response to an accelerator pedal operation. The method for correcting the pulley control pressure of the continuously variable transmission according to the present invention is to correct the pulley control pressure using the pulley ratio (speed ratio), which is the final target of control, without using a pressure sensor, and to learn the corrected pressure value. , an information collection step of receiving information necessary to determine whether to enter the learning mode from the electronic control device or sensors in the vehicle, and determining whether the current operation state of the vehicle identified from the received information meets a specific condition for entering the learning mode and a learning step of performing learning to correct the control pressure of the pulley by entering a learning mode when it is determined that the current operation state of the vehicle satisfies the specific condition. coasting drive) condition, and in the learning stage, immediately after entering the learning mode, the difference between the target pulley ratio and the actual pulley ratio of the variator or the difference between the change rate of the target pulley ratio and the actual pulley ratio change rate is compared, and the target pulley ratio change rate is compared. If the difference between the ratio and the actual pulley ratio or the difference between the target pulley ratio change rate and the actual pulley ratio change rate is equal to or greater than the corresponding set value, the pulley pressure is corrected through real-time pulley pressure control and the corrected pulley control pressure is applied to the new pulley. The gist is to learn and store with control pressure.

Description

Pulley controlling hydraulic pressure calibration method and device of CVT

The present invention relates to a method and apparatus for correcting the pulley control pressure of a continuously variable transmission, and more specifically, correcting the pulley control pressure using the pulley ratio, which is the final object of the control, without using a pressure sensor (a sensor that detects the pulley pressure). And it relates to a pulley control pressure correction method and apparatus of a continuously variable transmission for storing the corrected pressure value as a learning value.

A continuously variable transmission (hereinafter referred to as 'CVT') is similar in function to a general multi-stage automatic transmission, but unlike a multi-stage automatic transmission that optimizes driving force according to speed by combining gears, no gear is used for shifting. Instead, there is a primary pulley that receives power from the engine and a secondary pulley that transmits power to the wheels, and the two pulleys are connected by a belt.

Compared to general multi-speed automatic transmissions, CVT structurally operates closer to the optimal operating line (OOL), which reduces power loss and is advantageous in realizing high fuel efficiency. Therefore, there is an advantage of high efficiency compared to a general automatic transmission, and there is an advantage in that power can be transmitted without impact in performing low-speed/high-torque and high-speed/low-torque shifting.

The CVT's pulley ratio (transmission ratio) is determined by a variator. The variator is composed of the driving pulley, the driven pulley, and the belt. The drive pulley receives power from the engine and transmits power to the belt, and the driven pulley transmits the power received from the belt to the output shaft of the CVT. The pulley ratio of this CVT is determined by the distance from the contact point of each pulley and the belt to the rotation axis of the pulley.

The distance from the point of contact between each pulley and the belt to the axis of rotation of the pulley is again determined by the lateral force of each pulley. The shifting feeling of a CVT is determined by the starting torque and the engine speed (RPM) transmitted to the driver, and the starting torque and the engine speed (RPM) are again determined by the pulley ratio of the transmission. That is, various shifting sensations are realized according to the control of the pulley ratio in a specific situation.

CVT generally controls the pulley ratio using a pulley ratio map (transmission ratio map) that uses changes in vehicle speed and throttle opening rate (% or APS amount) as factors. When the target pulley ratio corresponding to the current vehicle speed and the throttle opening rate (%) is determined through the pulley ratio map, the control pressure of the driving pulley and the driven pulley is controlled to follow the target pulley ratio. At this time, when the shift is rapidly progressed toward the target pulley ratio, a shift shock may occur.

Therefore, there is a limit on the rate of change of the pulley ratio so that the pulley ratio does not change abruptly during shifting. That is, in the conventional CVT, when the target pulley ratio is determined through the pulley ratio map, the target pulley ratio limit value that limits the target pulley ratio change rate is determined, and the control pressure of the driving pulley and the driven pulley is determined according to the determined target pulley ratio limit value and the transmission input torque. It determines and implements shifting by controlling the pulley with the determined pressure.

The actuator that controls the shift of the CVT includes a solenoid valve and a spool valve. At this time, the solenoid valve controls the flow rate of the pressure fluid supplied to the driving pulley and the driven pulley under the control of the controller (eg, TCU), and the controller determines an appropriate pulley ratio according to the vehicle speed and the stow opening rate, and The shift is realized by outputting a corresponding duty control signal to the solenoid valve.

However, even if the solenoid valve and the spool valve constituting the actuator are manufactured using the same material and the same manufacturing method, there is a difference between the actual pressure and the target pressure supplied to the driving pulley and driven pulley for each vehicle when applied to a real vehicle due to deviations between individual units. There is a problem in that there is a difference, and therefore, there is a problem in that the shift timing varies from vehicle to vehicle even at the same vehicle speed and the same throttle opening rate.

As a method to solve the conventional pressure deviation (the difference between the actual pressure and the target pressure) caused by the deviation between individual units of the actuator that controls the shift of the CVT, a method using a hydraulic pressure sensor has been proposed. This is a technology that periodically measures the pulley control pressure with a hydraulic sensor, feedback-controls the pulley pressure based on the measurement result, and then learns the control value to follow the actual pressure to the target pressure.

However, the conventional pulley control pressure compensation technology of the hydraulic sensor method requires a separate hardware component such as a hydraulic sensor, so it is disadvantageous in terms of mass productivity and cost of the product. Since feedback control is impossible when pressure cannot be detected due to a failure, etc., there is a problem in that the pulley control pressure correction cannot be normally implemented.

Korean Patent No. 10-1756553 (Registration Date 2017. 07. 04)

The technical problem to be solved by the present invention is the pulley control pressure of a continuously variable transmission that can quickly and accurately correct the pulley control pressure using the pulley ratio, which is the final target of control, without using a pressure sensor (a sensor that detects the pulley pressure) It is intended to provide a calibration method and apparatus.

According to one aspect of the present invention as a means of solving the problem,

A method of compensating a pulley control pressure of a continuously variable transmission (CVT) in which a transmission ratio continuously changes according to an operation of an accelerator pedal, the method comprising:

(a) an information collection step of receiving information necessary to determine whether to enter the learning mode from the electronic control device or sensors in the vehicle;

(b) a state determination step of determining whether the current operation state of the vehicle identified from the received information satisfies a specific condition for entering the learning mode;

(c) when it is determined that the current operation state of the vehicle satisfies the specific condition, a learning step of entering a learning mode and performing learning to correct the control pressure of the pulley; includes,

The specific condition includes a coasting drive condition,

In the learning stage,

Immediately after entering the learning mode, the difference between the target pulley ratio and the actual pulley ratio of the variator or the difference between the change rate of the target pulley ratio and the actual pulley ratio change rate is compared.

If the difference between the target pulley ratio and the actual pulley ratio or the difference between the target pulley ratio change rate and the actual pulley ratio change rate is greater than or equal to the corresponding set value, the pulley pressure is corrected through real-time pulley pressure control and the corrected pulley control pressure We provide a method of compensating the pulley control pressure of a continuously variable transmission that learns and stores as a new pulley control pressure.

Preferably, the information necessary for determining whether to enter the learning mode collected in the information collection step includes shift lever position information, brake pressure information, driving road gradient information, engine torque information, vehicle speed information, transmission oil temperature information, vehicle Some or all of the mileage information may be included.

In addition, in the state determination step, if the shift lever is located in the D stage, the APS (Accelerator Position Sensor) is zero (0), and the brake pressure is less than the first set value, it is determined that the coasting drive condition is satisfied. can

More preferably, in the state determination step, the coasting drive condition is satisfied, the slope of the driving road is smaller than the absolute value of the second set value, the engine torque is smaller than the third set value, and the current If the vehicle speed is located in a specific speed section, the transmission oil temperature is higher than the fourth set value, and the difference between the accumulated mileage of the current vehicle and the accumulated mileage at the time when the previous learning is completed is equal to or greater than the fifth set value, entering the learning mode It can be determined that certain conditions for

And the learning step is,

c-1) entering the learning mode according to the learning start signal output when a specific condition for entering the learning mode is satisfied;

c-2) immediately after entering the learning mode, detecting the actual pulley ratio and the actual pulley ratio change rate of the variator (the amount of change in the actual pulley ratio for a predetermined time) and storing the detected value in the information storage unit;

c-3) determining whether the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit is equal to or greater than a predetermined number;

c-4) If the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit is less than a certain number, return to the information collection step and repeat the subsequent steps, and the actual pulley ratio and the actual pulley ratio stored in the information storage unit if the number of ratio change rates is equal to or greater than a predetermined number, calculating an average value of a predetermined number of actual pulley ratios and actual pulley ratio change rates stored in the information storage unit and storing the average values in the information storage unit;

c-5) The difference between the average value of the target pulley ratio and the actual pulley ratio of the variator determined by the vehicle speed and APS output immediately after entering the learning mode, the rate of change of the target pulley ratio (the amount of change in the target pulley ratio for a set time immediately after entering the learning mode) and determining whether to correct the pulley control pressure from the difference between the average values of the actual pulley ratio change rates; and

c-6) In the step c-5), the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio is set corresponding to the set value (the sixth set value) and the seventh set value), determining that the pulley control pressure correction is necessary and executing a predetermined process for the pulley control pressure correction; may include.

Here, the difference between the average value of the target pulley ratio and the actual pulley ratio and the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio in step c-5) is set corresponding to the set value (the sixth set value and the seventh set value) set value), it may be determined that the pulley control pressure is in a normal state and set to return to the information collection step.

Also, in step c-6), the difference between the target drive pulley speed and the actual drive pulley speed is compared with the absolute value of the correspondingly set eighth set value, and as a result of the comparison, if the difference is greater than the absolute value of the eighth set value, , judges that it is necessary to correct the driving pulley control pressure, corrects the driving pulley pressure through real-time driving pulley pressure control through PID control, learns and stores the corrected driving pulley control pressure as a new driving pulley control pressure, As a result of comparison, if the difference is less than the absolute value of the eighth set value, it is determined that the driven pulley control pressure needs to be corrected. The control pressure can be learned and stored as a new driven pulley control pressure.

According to another aspect of the present invention as a means of solving the problem,

A device for compensating the pulley control pressure of a continuously variable transmission (CVT) in which the transmission ratio continuously changes according to the operation of the accelerator pedal,

an information detection unit that receives information necessary to determine whether to enter a learning mode from an electronic control device or sensors in the vehicle, and provides the received information to a control unit;

a control unit for controlling the actuator of the continuously variable transmission based on the information provided by the information detection unit; and

The control unit is

It is determined whether the current operation state of the vehicle identified from the information provided by the information detection unit meets a specific condition for entering the learning mode, and when the specific condition is satisfied, it switches to the learning mode for correcting the control pressure of the pulley,

Immediately after switching the learning mode, the difference between the target pulley ratio and the actual pulley ratio of the variator or the difference between the change rate of the target pulley ratio and the actual pulley ratio change rate is compared.

If the difference between the target pulley ratio and the actual pulley ratio or the difference between the target pulley ratio change rate and the actual pulley ratio change rate is greater than or equal to the corresponding set value, the pulley pressure is corrected through real-time pulley pressure control and the corrected pulley control pressure It provides a pulley control pressure compensation device of a continuously variable transmission that learns and stores as a new pulley control pressure.

Preferably, the control unit corrects the control pressure of the pulley when the shift lever is located in the D stage, the APS (Accelerator Position Sensor) is zero (0), and the coasting drive condition is satisfied when the brake pressure is less than or equal to the first set value. You can switch to the learning mode for

More preferably, the control unit satisfies a coasting drive condition in which the shift lever is positioned at the D stage, the accelerator position sensor (APS) is zero, and the brake pressure is equal to or less than the first set value, and the information Among the information provided by the detector, the slope of the driving road is smaller than the absolute value of the second set value, the engine torque is smaller than the third set value, the current vehicle speed is located in a specific speed section, and the transmission oil temperature is the fourth set value. If higher and the difference between the accumulated mileage of the current vehicle and the accumulated mileage at the time immediately preceding learning is completed is equal to or greater than the fifth set value, it is possible to switch to the learning mode for adjusting the control pressure of the pulley.

The control unit includes an information storage unit for storing an actual pulley ratio and an actual pulley ratio change rate of a variator provided by the pulley ratio detection unit immediately after switching the learning mode, and the actual pulley ratio and the actual pulley ratio stored in the information storage unit If the number of ratio change rates is greater than or equal to a certain number, an average value derivation unit that calculates an average value of a certain number of actual pulley ratios and actual pulley ratio change rates stored in the information storage unit, and a variator determined by vehicle speed and APS output immediately after learning mode conversion Pulley control pressure from the difference between the average value of the target pulley ratio and the derived actual pulley ratio, the change rate of the target pulley ratio (the amount of change in the target pulley ratio for a predetermined time immediately after entering the learning mode), and the difference between the derived average value of the actual pulley ratio change rate A determination unit for determining whether to correct correction, and a set value set corresponding to the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio 7 set value) or more, it is determined that the pulley control pressure correction is necessary, and may include a pressure correction unit that executes control for correcting the pulley control pressure.

Here, the pressure compensator compares the difference between the target driving pulley speed and the actual driving pulley speed with the absolute value of the correspondingly set eighth set value, and as a result of the comparison, if the difference is greater than or equal to the absolute value of the eighth set value, the driving pulley It is judged that it is necessary to correct the control pressure, and the pressure of the driving pulley is corrected through real-time driving pulley pressure control through PID control, and the learning value is saved so that the corrected driving pulley control pressure can be learned and stored as a new driving pulley control pressure. provided to the department, and as a result of comparison, if the difference is less than the absolute value of the eighth set value, it is determined that the driven pulley control pressure needs to be corrected, and the driven pulley pressure is corrected through real-time driven pulley pressure control through PID control and the corrected driven pulley control pressure may be provided to the learning value storage unit to learn and store the new driven pulley control pressure.

According to an embodiment of the present invention, it is possible to quickly and accurately correct the pulley control pressure using the pulley ratio, which is the final object of control, without using a pressure sensor (sensor for detecting the pulley pressure), and as much as the use of a pressure sensor is excluded. It has advantages in terms of mass production and cost. In addition, there is an advantage that the pulley control pressure can be stably corrected compared to the conventional hydraulic sensor method.

1 is a schematic configuration diagram of a pulley control pressure guarantee apparatus of a continuously variable transmission according to an embodiment of the present invention.
2 is a view illustrating changes over time of various factors involved in shifting the continuously variable transmission in a coasting driving situation.
3 is a schematic configuration diagram of a control unit equipped with a processor programmed to perform a series of pulley control pressure correction and learning after the learning mode is switched.
4 is a flowchart for explaining a driving pulley control pressure correction method immediately after a kick-down shift of a continuously variable transmission according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Terms used in the following specification are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or It should be understood that the existence or addition of numbers, steps, operations, components, parts, or combinations thereof does not preclude in advance the possibility of addition.

Also, terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

In addition, terms such as “…unit”, “…unit”, “…module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. can

In addition, among the terms used to describe the present invention, 'pulley ratio of continuously variable transmission' is a term of 'drive pulley' and 'driven pulley' among variators involved in shifting of a continuously variable transmission (CVT). It means 'transmission ratio', that is, 'diameter ratio', and 'target gear ratio' is the 'drive pulley' output through the 'pulley ratio map' using the current vehicle speed and the throttle opening rate (%) as factors. It means 'target diameter ratio' of 'driven pulley'.

In the description with reference to the accompanying drawings, the same reference numerals will be assigned to the same components for the same components, and overlapping descriptions thereof will be omitted. In the description of the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

A pulley control pressure compensating device for a continuously variable transmission according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a pulley control pressure guaranteeing device for a continuously variable transmission according to an embodiment of the present invention, and FIG. 2 is experimental data illustrating changes over time of various factors involved in shifting a continuously variable transmission in a coaxing driving situation. am.

1 and 2 , the pulley control pressure compensating apparatus 1 according to an embodiment of the present invention detects and receives information necessary to determine whether to enter a learning mode from an electronic control device or sensors in a vehicle. It includes a detection unit 10 and a control unit 20 for controlling the actuator 50 of the continuously variable transmission based on the information provided by the information detection unit 10 .

The information detection unit 10 includes pulley speed detection units 16 and 17 for detecting the speed (rotational speed) of the driving pulley 72 and the driven pulley 74, and a pulley ratio (transmission ratio) from the detected pulley speed, and the pulley and a pulley ratio detection unit 18 for calculating the ratio change rate. The pulley speed detection unit again includes a driving pulley speed detection unit 16 for detecting the rotation speed of the driving pulley 72 and a driven pulley speed detection unit 17 for detecting the rotation speed of the driven pulley 74 .

The driving pulley speed detection unit 16 and the driven pulley speed detection unit 17 may preferably be a non-contact sensor that detects the rotational angular velocity of the pulley by recognizing a marker formed at a specific position in the rotational direction of the pulley, but is not limited thereto. Information detected by the two speed detection units (rotational speed information of the driving pulley 72 and driven pulley 74) is provided to a pulley ratio detection unit 18 constituting the information detection unit 10 and a control unit 20 to be described later, respectively. .

The pulley ratio detection unit 18 detects an actual pulley ratio (transmission ratio) from the detection information of the driving pulley speed detection unit 16 and the driven pulley speed detection unit 17 and calculates a pulley ratio change rate. The actual pulley ratio (speed ratio) may be a value obtained by dividing the drive pulley speed by the driven pulley speed (N _p /N _s ). It may be the slope of the actual pulley ratio.

The information detecting unit 10 also includes an APS (Accelerator Position Sensor) receiving unit 13 that receives information about the accelerator pedal operation from the ECU 60 . The APS receiver 13 detects the position (change amount) of the accelerator pedal of the continuously variable transmission vehicle. The detection information of the APS receiver 13 is transmitted to the control unit 20, and the control unit 20 determines a corresponding throttle valve control value based on the detection information and controls the opening rate of the throttle valve with the determined control value. .

In addition to this, the information detecting unit 10 includes a brake pressure receiving unit 14 that receives brake pressure information from the EUC 60 , a vehicle speed detecting unit 11 detecting the current vehicle speed, and the engine from the EUC 60 . and an engine torque receiver 15 for receiving information on torque.

Here, the configuration for detecting the brake pressure, the vehicle speed, and the engine torque is a known technology, and thus a detailed description thereof will be omitted below.

The control unit 20 controls the actuator 50 that controls the variator 70 of the continuously variable transmission based on the information provided by the information detection unit 10 . More specifically, the control unit 20 determines a corresponding target pulley ratio in the pulley ratio map 40 according to the current vehicle speed and the accelerator pedal operation amount (the output value of the APS receiver 13 ), and the current pulley ratio corresponds to the target pulley ratio. The control pressure of the driving pulley 72 and the driven pulley 74 is controlled through the actuator 50 to follow.

That is, the control unit 20 uses a dedicated map (the pulley ratio map 40) to optimize the driving performance at the current vehicle speed (output of the vehicle speed detection unit 11) and the accelerator pedal position (target pulley ratio). ), and by controlling the control pressure of the driving pulley 72 and the driven pulley 74 through the actuator 50 so that the shift can be made in accordance with the determined pulley ratio (target pulley ratio), the actual pulley ratio is set Follow the pulley.

In particular, the control unit 20 determines whether the current operation state of the vehicle identified from the information provided by the information detection unit 10 satisfies a specific condition for entering the learning mode, and when the condition is satisfied, to correct the control pressure of the pulley carry out learning To this end, the control unit 20 may be equipped with one or more processors operating by a program programmed to perform each step of the control method to be described later.

Specifically, when the operation state of the vehicle meets a specific condition for entering the learning mode, the control unit 20 switches the control mode to the learning mode for correcting the control pressure of the pulley. And the difference between the target pulley ratio and the actual pulley ratio or the change rate of the target pulley ratio and the actual pulley ratio change rate of the continuously variable transmission variator (70) is compared immediately after the learning mode is switched.

For reference, the target pulley ratio is automatically determined from the pulley ratio map 40 according to the current vehicle speed and the accelerator pedal operation amount (APS output value), and the actual pulley ratio is determined from the pulley ratio detection unit 18 based on the output of the pulley speed detection unit. is derived In addition, the target pulley ratio change rate is a change amount of the target pulley ratio for a predetermined time, and means the slope of the target pulley ratio in a box indicated by a dotted line in FIG. 2 .

The control unit 20 determines whether the difference between the target pulley ratio and the actual pulley ratio determined in the pulley ratio map 40 or the change rate of the target pulley ratio and the actual pulley ratio change rate according to the current vehicle speed and the accelerator pedal operation amount corresponds to each If it exceeds the set value, the pulley pressure is corrected through real-time pulley pressure control, and the corrected pulley control pressure is learned and stored as a new pulley control pressure.

A process of correcting the pulley control pressure performed by the controller 20 will be described in more detail.

When the operation state of the vehicle is the operation state for coasting drive, the controller 20 may determine that the specific condition for entering the learning mode is satisfied. More specifically, to correct the control pressure of the pulley when the shift lever is positioned in the D stage, the APS (Accelerator Position Sensor) is zero, and the coasting drive condition is satisfied when the brake pressure is less than or equal to the first set value. You can switch to the learning mode for

In some cases, the learning mode switching condition includes, in addition to the coercive driving condition, the road slope is smaller than the absolute value of the second set value, the engine torque is smaller than the third set value, and the current vehicle speed is in a specific speed section It may further include a condition in which the transmission oil temperature is higher than the fourth set value, and a difference (vehicle mileage) between the accumulated mileage of the current vehicle and the accumulated mileage at a time point when the previous learning is completed (vehicle mileage) is equal to or greater than the fifth set value.

Here, the road slope is a value (gradient value) derived from the G sensor output, and is a condition included to avoid a situation in which the vehicle speed rapidly increases or decreases while learning is performed in a steering driving situation, and a specific speed section is preferably It may be 40 to 60 km/h, but is not limited thereto. And, the temperature of the transmission oil is preferably 40° C. or higher as a condition in consideration of the reactivity of the hydraulic pressure controlling the pulley.

And the vehicle mileage condition is a condition in consideration of the fact that the pulley ratio is different due to the inertia of the pulley in the case of a vehicle having a certain mileage from the initially shipped vehicle, and at the same time, the burden of the control unit 20 due to frequent entry into the learning mode ( It is desirable to understand it as a condition for reducing computational load).

In the case of a coasting drive, as shown in the experimental data of FIG. 2 , changes in the target pulley ratio and the actual pulley ratio over time appear relatively stably. Therefore, in determining whether to correct the pulley control pressure, it is possible to more accurately determine whether the pulley control pressure correction is required compared to a sudden acceleration situation or sudden braking situation in which the target pulley ratio and the actual pulley ratio change rapidly.

That is why in the present invention, the coasting drive condition is set as the learning mode conversion condition for correcting the pulley control pressure.

3 is a schematic configuration diagram of a control unit equipped with a processor programmed to perform a series of pulley control pressure correction and learning after the learning mode is switched.

Referring to FIG. 3 , the control unit 20 may include an information storage unit 22 , an average value deriving unit 24 , a determination unit 26 , and a pressure correcting unit 28 . Each function constituting the control unit 20 will be described in more detail.

The information storage unit 22 stores the actual pulley ratio and the actual pulley ratio change rate of the variator 70 provided by the pulley ratio detection unit 18 immediately after the learning mode is switched. And the average value derivation unit 24 only when the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit 22 is equal to or greater than a certain number, the average value deriving unit 24 stores a certain number of actual pulley ratios and actual pulley ratios stored in the information storage unit 22 It serves to calculate the average value of the pulley ratio change rate.

Even if the learning mode switching conditions are the same, the actual pulley ratio detected in the learning process may vary slightly depending on the driving state of the vehicle. Therefore, if you use the average value of the results obtained with slightly different values under the same condition (the total of the actual pulley ratios measured for N times/N, the total of the actual pulley ratio changes derived for N times/N, where N is the number of measurements), the It can improve the learning accuracy.

Therefore, in the present invention, the average value of the actual pulley ratio measured several times and the actual pulley ratio change rate derived several times is used, and if the stored number (the number of storage of the actual pulley ratio and the actual pulley ratio change rate) is a certain number If the above condition is not satisfied, it may be programmed to repeat the above-described process (information collection-determining whether the condition is satisfied) until it is satisfied.

Information derived from the average value deriving unit 24 (the average value of the actual pulley ratio and the actual pulley ratio change rate at the time when a specific condition is satisfied) is provided to the determining unit 26 . The determination unit 26 analyzes the information provided by the average value derivation unit 24 and compares it with a corresponding target value, thereby controlling the pulley control pressure, more specifically, the fluid supplied to the driving pulley 72 and the driven pulley 74 . Determines whether to correct the current value of the solenoid valve that controls the pressure.

Specifically, the determination unit 26 determines the target pulley ratio of the variator 70 determined from the pulley ratio map according to the APS output and the vehicle speed immediately after switching the learning mode according to the above-described specific condition satisfaction and the derived actual pulley ratio. Whether to correct the pulley control pressure may be determined from the difference between the average value or the difference between the target pulley ratio change rate (the target pulley ratio change amount for a predetermined time immediately after entering the learning mode) and the average value of the derived actual pulley ratio change rate.

More specifically, the determination unit 26 determines whether the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio is a set value set corresponding to each (hereinafter, 'first pulley ratio'). 5' and '6th set value'), it can be determined that the pulley control pressure correction is necessary, and in this case, the pressure compensating unit 28 executes control for the pulley control pressure correction.

When the pressure compensating unit 28 corrects the pulley control pressure, the difference between the target driving pulley speed (derived from the pulley ratio map 40) and the actual driving pulley speed (the detected value of the driving pulley speed detecting unit 16) is matched. It is compared with the absolute value of the set set value (hereinafter referred to as the 'seventh set value'). And, as a result of the comparison, if the difference is greater than or equal to the absolute value of the eighth set value, it is determined that the control pressure of the driving pulley 72 needs to be corrected.

When it is determined that it is necessary to correct the driving pulley control pressure in this way, the pressure compensating unit 28 controls the driving pulley 72 in real time through PID control (Proportional Integral Derivative control), which is a kind of feedback control. The pressure at (72) is corrected and the corrected driving pulley control pressure (control current) is provided to the learning value storage unit 30 to learn and store the new driving pulley control pressure.

On the contrary, as a result of comparing the difference between the target driving pulley speed (derived from the pulley ratio map 40) and the actual driving pulley speed (the detected value of the driving pulley speed detection unit 16) with the absolute value of the eighth set value, the difference If is less than the absolute value of the eighth set value, it is determined that there is no problem in the control pressure of the driving pulley and there is a problem in the control pressure of the driven pulley 74 . That is, it is determined that the control pressure of the driven pulley 74 needs to be corrected.

When it is determined that it is necessary to correct the driven pulley control pressure as described above, the pressure of the driven pulley 74 through real-time driven pulley 74 pressure control through PID control (Proportional Integral Derivative control), which is a kind of feedback control. and provides the learning value storage unit 30 to learn and store the corrected driving pulley control pressure (control current) as a new driving pulley control pressure.

Meanwhile, the learning value (corrected control pressure value) stored in the learning value storage unit 30 may be used as a control value for controlling the pressure of the driving pulley 72 or the driven pulley 74 in a shift situation after learning.

In FIG. 1, reference numeral 73, which is not described, denotes a belt constituting a variator of the continuously variable transmission.

Hereinafter, a process of correcting the pulley control pressure performed by the above-described pulley control pressure correcting apparatus of the continuously variable transmission will be described with reference to the flowchart of FIG. 4 . For convenience of description, the configuration shown in FIG. 1 described above will be described with reference to the corresponding reference numerals.

Referring to FIG. 3 , the pulley control pressure correction process is largely composed of an information collection step ( S100 ), a state determination step ( S200 ), and a learning step ( S300 ). At this time, in the information collection step (S100), information necessary to determine whether to enter the learning mode from the electronic control device or sensors in the vehicle is received, and in the state determination step (S200), the vehicle operation state is determined based on the received information.

Information necessary for determining whether to enter the learning mode in the information collection step S100 includes shift lever position information, brake pressure information, driving road gradient information, engine torque information, vehicle speed information, transmission oil temperature information, vehicle mileage information, etc. may include In some cases, only some of the listed information may be included or additional information may be required in addition to the listed information.

In the state determination step (S200), the information received in the information collection step (S100) is analyzed. And it is determined whether the current operation state of the vehicle grasped from the received information meets a specific condition for entering the learning mode. Here, the specific condition for entering the learning mode may include a coasting drive situation in which the vehicle moves only with driving inertia without manipulation of the accelerator pedal.

Preferably, if the shift lever is positioned in the D stage, the accelerator position sensor (APS) is zero, and the brake pressure is less than or equal to the first set value, it is determined that the coasting drive condition is satisfied, and the subsequent steps ( A learning step (S300)) for correcting the control pressure of the pulley may be performed.

In some cases, the learning mode entry condition includes: in addition to the coercive driving condition, the road slope is smaller than the absolute value of the second set value, the engine torque is smaller than the third set value, and the current vehicle speed is in a specific speed section location, the transmission oil temperature is higher than the fourth set value, and a difference (vehicle mileage) between the accumulated mileage of the current vehicle and the accumulated mileage at a time point when the previous learning is completed may further include a condition greater than or equal to the fifth set value.

Here, the road slope is a value (gradient value) derived from the G sensor output, and is a condition included to avoid a situation in which the vehicle speed rapidly increases or decreases while learning is performed in a steering driving situation, and a specific speed section is preferably It may be 40 to 60 km/h, but is not limited thereto. And, the temperature of the transmission oil is preferably 40° C. or higher as a condition in consideration of the reactivity of the hydraulic pressure controlling the pulley.

And the vehicle mileage condition is a condition in consideration of the fact that the pulley ratio is different due to the inertia of the pulley in the case of a vehicle having a certain mileage from the initially shipped vehicle, and at the same time, the burden of the control unit 20 due to frequent entry into the learning mode ( It is desirable to understand it as a condition for reducing computational load).

In the learning step (S300), immediately after entering the learning mode, the difference between the target pulley ratio and the actual pulley ratio of the variator 70 or the difference between the change rate of the target pulley ratio and the actual pulley ratio change rate is compared, and each difference corresponds to If it exceeds the set value, the pulley pressure is corrected through real-time pulley pressure control, and the corrected pulley control pressure is learned and stored as a new pulley control pressure.

The learning step (S300) will be looked at in more detail.

The learning step (S300) includes a step (S302) of entering the learning mode according to the learning start signal output at the time when a specific condition for entering the learning mode is satisfied. Also, immediately after entering the learning mode, detecting the actual pulley ratio and the actual pulley ratio change rate of the variator 70 (the amount of change in the actual pulley ratio for a predetermined time) and storing the detected value in the information storage unit 22 (S304) ) is included.

Next, a step S306 of determining whether the number of the actual pulley ratio and the actual pulley ratio change rate (the number of times of measuring and storing the actual pulley ratio and the actual pulley ratio change rate) stored in the information storage unit 22 is equal to or greater than a certain number (S306) is performed . If the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit 22 is less than a predetermined number, it returns to the information collection step S100 and repeats the subsequent steps.

If the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit 22 is greater than or equal to a certain number, an average value of a predetermined number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit 22 is calculated and the calculated The value is stored again in the information storage unit 22 (S308), and whether to correct the pulley control pressure is determined using the stored average value (the average value of the actual pulley ratio and the average value of the actual pulley ratio change rate) (S310).

In step S310, preferably, immediately after entering the learning mode, the difference between the average value of the target pulley ratio of the variator and the actual pulley ratio determined according to the vehicle speed and the accelerator pedal operation amount (APS output) or the rate of change of the target pulley ratio (set immediately after entering the learning mode) It is possible to determine whether to correct the pulley control pressure based on the difference between the target pulley ratio change amount over time) and the average value of the actual pulley ratio change rate.

If, as a result of the comparison in step S310, the difference between the average value of the target pulley ratio and the actual pulley ratio and the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio are respectively corresponding set values (the sixth setting value and the seventh setting value) value), it is determined that the pulley control pressure is normal, and the process returns to step S100 and repeats the subsequent steps, but in this case, the vehicle mileage condition included in step S200 is caught and the process can be terminated without further progress.

On the contrary, in step S310, the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio is set corresponding to the set value (the sixth set value and the seventh set value) ), it is determined that the pulley control pressure correction is necessary and a predetermined process for the pulley control pressure correction may be executed (S312).

Step S312 specifically includes comparing the difference between the target driving pulley speed and the actual driving pulley speed with the absolute value of the correspondingly set eighth set value. As a result of comparison, if the difference is greater than or equal to the absolute value of the eighth set value, it is determined that the driving pulley control pressure needs to be corrected, and the driving pulley pressure is corrected through real-time driving pulley pressure control through PID control. Then, the corrected driving pulley control pressure is learned and stored as a new driving pulley control pressure.

On the contrary, as a result of comparing the difference between the target driving pulley speed and the actual driving pulley speed with the absolute value of the correspondingly set eighth set value, if the difference is less than the absolute value of the eighth set value, the driven pulley control pressure can be corrected Judging that it is necessary, it compensates the driven pulley pressure through real-time driven pulley pressure control through PID control, and learns and stores the corrected driven pulley control pressure as a new driven pulley control pressure.

Among the methods to solve the pressure deviation (the difference between the actual pressure and the target pressure) that occur in CVT vehicles, the conventional method of using a hydraulic sensor requires a separate hardware component, which is disadvantageous in terms of mass productivity and cost of the product. In particular, since feedback control is impossible when the hydraulic pressure sensor is abnormal, there is a problem that the pulley control pressure correction cannot be performed normally.

On the other hand, in the present invention, the pulley control pressure can be quickly and accurately corrected using the pulley ratio, which is the final object of control, without using a pressure sensor (sensor for detecting the pulley pressure), and the use of a pressure sensor is not used, so it is not necessary for mass production. There are advantages in terms of cost. In addition, it has the advantage of stably correcting the pulley control pressure compared to the hydraulic sensor method.

In the above detailed description of the present invention, only specific embodiments thereof have been described. However, it is to be understood that the present invention is not limited to the particular form recited in the detailed description, but rather, it is to be understood to cover all modifications and equivalents and substitutions falling within the spirit and scope of the present invention as defined by the appended claims. should be

1: Pulley control pressure compensation device
10: information detection unit
11: vehicle speed detection unit
12: oil temperature detection unit
13: APS receiver
14: brake pressure receiver
15: engine torque receiver
16: drive pulley speed detection unit
17: driven pulley speed detection unit
18: pulley ratio detection unit
20: control unit
22: information storage unit
24: average value derivation unit
26: judgment unit
28: pressure compensation unit
30: learning value storage unit
40: Pulibi Map
50: actuator
60: ECU
70: Variator
72: drive pulley
73: belt
74: driven pulley

Claims (12)

A method of compensating a pulley control pressure of a continuously variable transmission (CVT) in which a transmission ratio continuously changes according to an operation of an accelerator pedal, the method comprising:
(a) an information collection step of receiving information necessary to determine whether to enter the learning mode from the electronic control device or sensors in the vehicle;
(b) a state determination step of determining whether the current operation state of the vehicle identified from the received information satisfies a specific condition for entering the learning mode;
(c) when it is determined that the current operation state of the vehicle satisfies the specific condition, a learning step of entering a learning mode and performing learning to correct the control pressure of the pulley; includes,
The specific condition includes a coasting drive condition,
The learning step is
c-1) entering the learning mode according to the learning start signal output when a specific condition for entering the learning mode is satisfied;
c-2) immediately after entering the learning mode, detecting the actual pulley ratio and the actual pulley ratio change rate of the variator (the amount of change in the actual pulley ratio for a predetermined time) and storing the detected value in the information storage unit;
c-3) determining whether the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit is equal to or greater than a predetermined number;
c-4) If the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit is less than a certain number, return to the information collection step and repeat the subsequent steps, and the actual pulley ratio and the actual pulley ratio stored in the information storage unit if the number of ratio change rates is equal to or greater than a predetermined number, calculating an average value of a predetermined number of actual pulley ratios and actual pulley ratio change rates stored in the information storage unit and storing the average values in the information storage unit;
c-5) The difference between the average value of the target pulley ratio and the actual pulley ratio of the variator determined by the vehicle speed and APS output immediately after entering the learning mode, the rate of change of the target pulley ratio (the amount of change in the target pulley ratio for a set time immediately after entering the learning mode) and determining whether to correct the pulley control pressure from the difference between the average values of the actual pulley ratio change rates; and
c-6) In the step c-5), the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the change rate of the target pulley ratio and the average value of the change rate of the actual pulley ratio is set corresponding to the set value (the sixth set value) and seventh set value) or more, correcting the pulley control pressure and learning and storing the corrected pulley control pressure as a new pulley control pressure;
The method of claim 1,
The information required to determine whether to enter the learning mode collected in the information collection step is,
A method of compensating a pulley control pressure of a continuously variable transmission including some or all of shift lever position information, brake pressure information, driving road gradient information, engine torque information, vehicle speed information, transmission oil temperature information, and vehicle mileage information.
The method of claim 1,
In the state determination step,
When the shift lever is positioned at the D stage, the accelerator position sensor (APS) is zero, and the brake pressure is less than or equal to the first set value, the pulley control pressure of the continuously variable transmission is determined to satisfy the coasting drive condition. Calibration method.
4. The method of claim 1 or 3,
In the state determination step,
While satisfying the above coasting drive condition,
The slope of the driving road is smaller than the absolute value of the second set value,
The engine torque is less than the third set value,
The current vehicle speed is located in a specific speed range,
The transmission oil temperature is higher than the fourth set value;
If the difference between the accumulated mileage of the current vehicle and the accumulated mileage at the time when the previous learning is completed is equal to or greater than the fifth set value,
A method of correcting a pulley control pressure of a continuously variable transmission for determining that a specific condition for entering the learning mode is satisfied.
delete The method of claim 1,
In step c-5), the difference between the average value of the target pulley ratio and the actual pulley ratio and the difference between the change rate of the target pulley ratio and the average value of the actual pulley ratio change rate are set corresponding to the set values (the sixth set value and the seventh set value) value), it is determined that the pulley control pressure is in a normal state, and the method of correcting the pulley control pressure of the continuously variable transmission returns to the information collection step.
The method of claim 1,
In step c-6),
Comparing the difference between the target drive pulley speed and the actual drive pulley speed with the absolute value of the correspondingly set eighth set value,
As a result of comparison, if the difference is greater than or equal to the absolute value of the eighth set value, it is determined that the driving pulley control pressure needs to be corrected, and the driving pulley pressure is corrected and corrected driving through real-time driving pulley pressure control through PID control. It learns and stores the pulley control pressure as a new driving pulley control pressure,
As a result of comparison, if the difference is less than the absolute value of the eighth set value, it is determined that the driven pulley control pressure needs to be corrected. A pulley control pressure compensation method of a continuously variable transmission that learns and stores the control pressure as a new driven pulley control pressure.
A device for compensating the pulley control pressure of a continuously variable transmission (CVT) in which the transmission ratio continuously changes according to the operation of the accelerator pedal,
an information detection unit that receives information necessary to determine whether to enter a learning mode from an electronic control device or sensors in the vehicle, and provides the received information to a control unit;
a control unit for controlling the actuator of the continuously variable transmission based on the information provided by the information detection unit; and
The control unit is
It is determined whether the current operation state of the vehicle identified from the information provided by the information detection unit meets a specific condition for entering the learning mode, and when the specific condition is satisfied, the vehicle switches to the learning mode for correcting the control pressure of the pulley,
An information storage unit for storing the actual pulley ratio and the actual pulley ratio change rate of the variator provided by the pulley ratio detection unit immediately after switching the learning mode;
If the number of the actual pulley ratio and the actual pulley ratio change rate stored in the information storage unit is greater than or equal to a certain number, an average value derivation unit for calculating an average value of a predetermined number of actual pulley ratios and the actual pulley ratio change rate stored in the information storage unit;
The difference between the average value of the derived actual pulley ratio and the target pulley ratio of the variator determined by the vehicle speed and APS output immediately after switching to the learning mode, or the change rate of the target pulley ratio (the amount of change in the target pulley ratio for a predetermined time immediately after entering the learning mode) and the above a determination unit that determines whether to correct the pulley control pressure from the difference between the derived average values of the actual pulley ratio change rates;
When the difference between the average value of the target pulley ratio and the actual pulley ratio or the difference between the average value of the change rate of the target pulley ratio and the actual pulley ratio change rate is greater than or equal to the corresponding set value (the sixth set value and the seventh set value), pulley control A pulley control pressure compensating device for continuously variable transmission comprising a pressure compensating unit that corrects the pressure and provides correction information to the learning value storage unit to learn and store the corrected pulley control pressure as a new pulley control pressure.
9. The method of claim 8,
The control unit is
When the shift lever is located in the D stage, the APS (Accelerator Position Sensor) is zero, and the brake pressure is below the first set value, the learning mode is changed to correct the control pressure of the pulley when the coasting drive condition is satisfied. A pulley-controlled pressure compensating device for a continuously variable transmission.
9. The method of claim 8,
The control unit is
With the shift lever positioned in the D stage, the APS (Accelerator Position Sensor) is zero, and the brake pressure is below the first set value, the coasting drive condition is satisfied.
Among the information provided by the information detection unit, the slope of the driving road is smaller than the absolute value of the second set value,
The engine torque is less than the third set value,
The current vehicle speed is located in a specific speed range,
The transmission oil temperature is higher than the fourth set value;
If the difference between the accumulated mileage of the current vehicle and the accumulated mileage at the time when the previous learning is completed is equal to or greater than the fifth set value,
A pulley control pressure compensating device of a continuously variable transmission that switches to a learning mode for adjusting the control pressure of the pulley.
delete 9. The method of claim 8,
The pressure compensator,
Comparing the difference between the target drive pulley speed and the actual drive pulley speed with the absolute value of the correspondingly set eighth set value,
As a result of comparison, if the difference is greater than or equal to the absolute value of the eighth set value, it is determined that the driving pulley control pressure needs to be corrected, and the driving pulley pressure is corrected and corrected driving through real-time driving pulley pressure control through PID control. Provide the learning value storage unit to learn and store the pulley control pressure as a new driving pulley control pressure,
As a result of comparison, if the difference is less than the absolute value of the eighth set value, it is determined that the driven pulley control pressure needs to be corrected. A pulley control pressure compensating device of a continuously variable transmission that provides the learning value storage unit to learn and store the control pressure as a new driven pulley control pressure.

Images