KR20190078412A - Clutch creep torque control apparatus and control method thereof - Google Patents

Abstract

The present invention relates to a clutch creep torque control apparatus and a control method thereof, which can reduce judder when a vehicle with a dual clutch transmission creeps. The clutch creep torque control apparatus comprises: a control signal collection unit collecting a control signal when a vehicle creeps; a calculation unit receiving the control signal to determine whether the control signal corresponds to a judder generation area, and calculating compensation clutch torque; and a control unit controlling a clutch in accordance with the compensation clutch torque.

Description

CLUTCH CREEP TORQUE CONTROL APPARATUS AND CONTROL METHOD THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a clutch creep torque control device and a control method thereof, and more particularly, to a clutch creep torque control device and a control method for reducing a judder during a creep traveling of a dual clutch transmission vehicle.

Recently, a dual clutch transmission (hereinafter referred to as DCT) capable of simultaneously achieving the driving convenience of the automatic transmission, the fuel economy of the manual transmission, and the high power efficiency has been developed. The DCT is a type of automatic transmission (hereinafter referred to as AMT) based on a manual transmission system, and has two torque transmission axes to reduce or prevent torque drop during shifting, thereby ensuring shift quality. This system has the advantage of high fuel efficiency. However, since DCT or AMT tighten the clutch by directly coupling the clutch without the torque converter, the clutch control performance affects the oscillation and shifting performance of the vehicle. As described above, the clutch used in the DCT or AMT is divided into a wet clutch controlled by hydraulic pressure and a dry clutch having a simple mechanical operation. In a normal driving situation, the dry clutch is more than 3% It is well known that it is known as technology to improve fuel efficiency. However, when the dry clutch is overheated, such as when the vehicle is starting from the back plate, there is a problem that the clutch performance is degraded, for example, the friction coefficient of the dry clutch changes or vibration occurs. That is, the phenomenon in which the dry clutch vibrates in a specific slip section according to the difference in rotational speed between the engine flywheel and the clutch disk in accordance with the weight or rigidity of the vehicle as well as the high temperature condition of the dry clutch as described above is referred to as a judder . Such judder causes the driver to feel the longitudinal vibration of the vehicle, which lowers the drivability and negatively affects the durability of the transmission.

There are two types of judder. Geometric girders and frictioners. The geometric judder is caused by the clamp load variation, and the friction judder is caused by the pacing friction characteristics of the clutch disc. The judder phenomenon may occur during creep running or oscillation.

Creep driving means that the vehicle moves only by the idle RPM of the engine or the electric power of the motor without depressing the accelerator pedal. It is usually a creep when the road is blocked or when the driver is willing to slow down. The creep torque means torque at the time of creep driving. In general, the creep torque only occurs when the vehicle is in a low speed or stopped state and the driver does not have the acceleration will, that is, when the pedal is not pressed. The generated creep torque is generated by the engine, at which time the engine generates a creep torque with minimal power.

The mechanism of generating a jerk at the time of creep travel or oscillation will be described in the following order. First, a high temperature is generated in the double clutch. Durability deterioration of clutch parts and deterioration of disk pacing occur due to high temperature. Next, vibration of the clutch occurs due to unstable pressure plate wear and pacing friction coefficient. The vibration of the clutch acts as a factor to cause tremor when starting the vehicle.

KR 10-2014-0083767 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a clutch creep torque control apparatus and a control method for reducing a judder at the time of traveling a creep of a dual clutch transmission vehicle.

According to an aspect of the present invention, there is provided a clutch creep torque control method including the steps of: collecting a control signal at the time of oscillation or creep of a vehicle; confirming whether the region is a judder generating region based on the control signal; Calculating a compensating clutch torque, and controlling the clutch based on the compensating clutch torque.

The control signal includes at least one or more information on the RPM of the engine and the input shaft, information on the torque of the engine and the clutch, information on the temperature of the clutch plate, information on the touch point, .

The step of determining whether the judder is generated is determined as a region where the judder occurs if the difference between the engine RPM and the input shaft RPM is equal to or less than the first RPM and equal to or greater than the second RPM.

The clutch creep torque control method according to the embodiment further includes checking whether the gear lever is located when the judder has occurred, after confirming whether the region is the judder generating region.

Wherein the step of calculating the compensating clutch torque includes the step of calculating using the creep torque included in the control signal and updating the creep torque included in the control signal by adding the creep torque and the compensating clutch torque, Is limited to a predetermined ratio (%) or less of the creep torque.

Wherein the step of calculating the compensating clutch torque includes an area determining step of determining whether it is a geometric judder area or a friction judder area and a calculating step of calculating a compensating clutch torque according to the determined judder area.

And the area determination step is determined using the sleep RPM.

Wherein the calculation is performed on the basis of the temperature of the clutch plate (Clutch Pressure Plate 1/2) and the touch point in the case of the geometric judder region, and in the case of the friction judder region, Plate 1/2, Clutch Center Plate) and the friction coefficient of the clutch disc.

The clutch creep torque control apparatus according to another embodiment of the present invention includes a control signal collection unit for collecting a control signal at the time of traveling a creep, an operation unit for determining whether the control signal corresponds to a judder generation region, And a control unit for controlling the clutch in accordance with the compensating clutch torque, wherein the control signal includes information on the RPM of the engine and the input shaft, information on the torque of the engine and the clutch, information on the temperature of the clutch disk, And information on the friction coefficient of the clutch disc.

The computing unit may calculate the compensating clutch torque using the creep torque included in the control signal, and update the creep torque of the control signal to a value obtained by adding the creep torque and the compensating clutch torque.

The present invention controls the clutch using the compensating clutch torque according to the geometric judder and the friction judder during the creep traveling of the dual clutch transmission vehicle, thereby improving the shifting feeling at the time of oscillation and creep.

The present invention reduces the occurrence of judder, thereby improving the durability of the transmission.

1 is a graph for explaining a clutch control method for creep traveling of a dual clutch transmission vehicle.
2 is a graph showing actual data of judder at the time of creep traveling of a dual clutch transmission vehicle.
3 is a view showing a clutch creep torque control apparatus according to an embodiment of the present invention.
4 is a graph exemplarily showing a judder generating region at the time of creep traveling of a dual clutch transmission vehicle.
5 is a graph showing changes in characteristics of a touch point according to temperature.
6A is a graph showing the clutch stability according to the slope of the friction coefficient.
6B is a graph showing the friction coefficient according to the slip speed.
7 is a flowchart showing a clutch creep torque control method according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be construed as ideal or overly formal in meaning unless explicitly defined in the present application Should not.

Hereinafter, a clutch creep torque control apparatus and a control method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a graph for explaining a clutch control method for creep traveling of a dual clutch transmission vehicle.

 Referring to the graph of FIG. 1 (a), A1 is the idle RPM of the engine and A2 is the speed of the input shaft. The creep starts at the point X1, the input shaft speed gradually increases, and the creep is gradually reduced at the point X2.

Referring to the graph of FIG. 1 (b), OUT1 is the creep target velocity setting value and OUT2 is the creep target velocity to which the filter is applied. OUT_real is the actual output speed. Judder occurs in the process where Output Speed is controlled to OUT2 (creep target speed), especially C2 in Figure 1 (c) graph.

Referring to the graph of FIG. 1 (c), clutch control is performed in such a manner that the clutch is engaged at the point X1, the clutch torque is gradually increased (C1), and the clutch torque is gradually decreased (C2) .

2 is a graph showing actual data of judder at the time of creep traveling of a dual clutch transmission vehicle.

Referring to FIG. 2, the input shaft RPM, the I2 curve, vibrates before converging (J1 box). I1 is a curve representing engine RPM.

In the P region, the I3 (clutch torque) curve rises and falls gradually and the I2 (input shaft RPM) gradually increases as the clutch is engaged and disengaged.

In the Q region, a judder occurs as the clutch torque gradually decreases, and this portion is indicated by a dotted line. This J2 region is called the resonance area.

The R region is out of the region where the judder occurs and the I2 (input shaft RPM) curve shows convergence without vibration.

In order to reduce the occurrence of this jerk, the compensation of the clutch torque which offsets the vibration of the input shaft RPM is required, and the compensation is made in the Q region corresponding to the resonance area. Compensation Torque means the torque to be applied in addition to the clutch torque for creep travel in the Q region. Although shown in bold with dotted lines for the sake of explanation, it does not mean the actual value of the compensation torque and is illustrative.

3 is a diagram showing a configuration of a clutch creep torque control apparatus 100 according to an embodiment of the present invention.

3, the clutch creep torque control apparatus 100 includes a control signal collection unit 101, an operation unit 102, and a control unit 103. [

The control signal collection unit 101 collects control signals from the sensors 10 of the vehicle at the time of oscillation and creep. The sensor 10 of the vehicle means sensors for detecting RPM, torque, temperature, and the like. The control signal collected by the control signal collection unit 101 may include a control signal updated by the operation unit 102. [

The control signal may include four pieces of information. For example, information about the RPM, information about the torque, information about the temperature, and other information.

More specifically, the information about the RPM may include an engine RPM, an input shaft RPM, an output RPM, an error RPM, and the like.

The information on the torque may include engine torque, flywheel torque, clutch torque, creep torque, and the like.

The temperature information may include the temperature of the clutch center plate, the temperature of the clutch pressure plate (Clutch Pressure Plate), and the like.

Other information may include information about the touch point, friction coefficient of the clutch disc, and a factor for calculating the compensating clutch torque according to the judder. The touch point refers to a stroke in which power is transmitted to the vehicle based on the actuator of the clutch.

In the present specification, the torque to be applied to reach the target RPM during the creep traveling will be referred to as a reference torque as the creep torque. This means that a compensating clutch torque is added to the Creep Torque Old during feedback control to include an updated torque value.

The control signal collecting unit 101 collects the control signals at the time of oscillation and creep traveling and transmits the collected control signals to the calculating unit 102.

The calculation unit 102 determines whether the region is a judder generating region using the control signal received from the control signal collecting unit 101, and calculates a compensation clutch torque. The calculating unit 102 calculates the compensating clutch torque and transmits it to the control unit 103. [ According to another embodiment of the present invention, the calculating unit 102 calculates the compensating clutch torque using the creep torque included in the received control signal, and adds the compensating clutch torque into the control signal as a sum of the creep torque and the compensating clutch torque The updated creep torque can be updated.

The control section (103) controls the clutch (20) based on the compensating clutch torque transmitted from the calculating section (102).

4 is a graph exemplarily showing a judder generating region at the time of creep traveling of a dual clutch transmission vehicle.

Referring to FIG. 4, the point 1 is a point where the difference between the engine RPM and the input shaft RPM (slip RPM) is E rpm. If the slip RPM is less than E rpm in the right direction of the point 1, it enters the judder generating region (entry condition of the judder occurrence area, Entry Condition). The second point is the point at which the slip RPM is T rpm. If the slip RPM is less than T rpm, the right hand side of the two points will deviate from the judder generation area (exit condition of judder occurrence area, Exit Condition). Therefore, the judder generating region in FIG. 4 can be said that the difference between the engine RPM and the input shaft RPM is equal to or less than E rpm and equal to or greater than T rpm. As the slip RPM, E rpm, which is the entry condition of the judder occurrence area, and T rpm, which is the escape condition of the judder occurrence area, are predetermined values, which are determined by the experimental data and may vary depending on the vehicle and the transmission.

5 is a graph showing changes in characteristics of a touch point according to temperature.

Referring to FIG. 5, the odd is the first clutch and the even is the second clutch. The left vertical axis represents the stroke value corresponding to the touch point, and the right vertical axis represents the difference between the maximum value and the minimum value of the stroke. In the case of the clutch No. 1, the touch point value gradually increases as the temperature rises. In the case of the second clutch, as the temperature rises, the touch point tends to decrease gradually. The experimental values for the calculation of the geometric judder torque can be obtained using the tendency of the touch point to show different values depending on the temperature, which will be described in more detail in FIG.

6A is a graph showing the clutch stability according to the slope of the friction coefficient.

Referring to FIG. 6A, as the slip speed increases in the graph, as the friction coefficient increases, the slope is positive and the clutch is stable. As the slip speed increases, as the friction coefficient decreases, the slope becomes negative and the clutch is unstable. Judder occurs when the clutch characteristic is unstable.

6B is a graph showing the friction coefficient according to the slip speed.

In FIG. 6B, characteristic curves of the friction coefficient according to the slip velocity are shown by temperature. In the L1 curve and the L2 curve, the slope of the creep region is negative, and the clutch characteristic is unstable. Therefore, it can be expected that judder will occur in the creep region at room temperature (Room Temp) and 50 deg. The remaining L3 to L6 curves have a positive slope and the clutch characteristics are stable, so no judder occurs. In general, it can be seen that all the curves converge to constant friction coefficient values as the slip speed increases.

7 is a flowchart showing a clutch creep torque control method according to an embodiment of the present invention.

Control starts with the oscillation or creep of the dual clutch transmission vehicle. The control signal collecting unit 101 collects control signals from the sensors 10 at the time of oscillation or creep of the vehicle (S210). The collected control signals are the same as those described in Fig. The calculating unit 102 determines whether the judder is generated using the control signal (S220).

When it is determined that the calculation unit 102 corresponds to the area where the judder is generated, the lever position of the gear is checked (S230). Table 1 shows gears and clutches according to the lever position.

Lever Position D R Gear 1st stage R stage clutch Odd Even

The signals according to the lever position are basically P, R, N and D. The signals to check for control are D, R. When the lever is at D, the gear is one stage and the Odd clutch is engaged. If the lever is at R, the gear is in R and the even clutch is engaged. It is determined whether the lever position is D or R, and clutch control corresponding to the lever position is performed. Then, the calculation unit 102 calculates a compensation clutch torque (S240). The calculation of the compensation clutch torque is calculated using the creep torque included in the control signal. There are two types of judder, and the compensating clutch torque is calculated by the following equation (1).

The compensating clutch torque is the sum of the value obtained by multiplying the geomagnetic judder torque by the factor 1 and the value obtained by multiplying the friction judder torque by the factor 2. [

The determination method of the factor 1 and the factor 2 will be described with reference to FIG. The judder occurrence area is the sum of the geometric judder occurrence area (G area) and the friction judder occurrence area (F area). That is, there may be regions where two types of judder coexist because of overlapping regions, and there may be a region where only one kind of judder exists. In the case of the area where the G area and the F area overlap, both the factor 1 and the factor 2 are used to calculate the compensation clutch torque. As the other case, the compensation clutch torque is calculated using the factor 1 or the factor 2 only in the area where the G area and the F area do not overlap. The area is distinguished by slip RPM. The values of concrete Factor 1 and Factor 2 are selected according to the ratio (%) of slip RPM as shown in Table 2 below.

Item Slip ratio (Engine rpm - Input Shaft rpm) / Engine rpm * 100 (%) 0 25 50 75 100 Factor - - - - -

In Table 2, the concrete value of the factor according to the slip ratio is not a theoretical value but a data value according to the test result. Therefore, it may vary depending on the vehicle type and the transmission. Regarding the selection of the factor value, the factor value is set to 0 in the non-judder area and the compensation clutch torque is selected so that it does not exceed the creep torque much.

The geometric judder torque is calculated taking into account the temperature of the clutch plate (Clutch Plate), which is considered to be the biggest influence on the transmission system, and the touch point of the clutch plate.

The geometric judder torque can be calculated using the following equation (2).

In Equation (2), the geometric judder torque can be obtained by multiplying the creep torque by Map1. Map1 is one of the values of the data sheet which is formed considering the change of the touch point caused by the temperature. The form of the data sheet of Map1 is shown in Table 3 below.

Item Clutch plate temperature Area1 Area2 Area3 Area4 0 50 100 150 200 250 300 350
Touch point T1 - - - - - - - - T2 - - - - - - - - T3 - - - - - - - - T4 - - - - - - - - T5 - - - - - - - -

In Table 3, the geomagnetic judder torque is calculated by selecting a value corresponding to the temperature of the clutch plate included in the control signal and information about the touch point. The values used in Table 3 are not values with physical quantities, but general constants, which are selected using experiential values based on test data. As shown in FIG. 5, since the tendency of the touch point according to the temperature is ambiguous, it is difficult to apply the generalized formula to the entire region. The specific value may vary depending on the vehicle type or the transmission, and the range of the compensating clutch torque to be finally calculated is set to be within a certain percentage (%) of the creep torque.

Friction judder torque is a major factor in the friction material properties of the clutch disc. In general, it dominates the u-V (friction coefficient-slip speed) characteristic of the clutch disc and there are differences in characteristics depending on the friction material component.

The friction judder torque can be obtained by the following equation (3).

In equation (3), the friction judder torque can be obtained by multiplying the creep torque by Map2. Map2 is one of the values of the data sheet which is formed considering the change of friction coefficient of the clutch disc according to the temperature.

As shown in FIG. 6B, since the friction coefficient initially converges to a constant value, the friction coefficient is selected in association with the mileage information, and the data sheet regarding Map2 is constructed in consideration of the stable region and the unstable region according to the temperature characteristic. The data sheet regarding Map2 is configured as shown in Table 4 below.

Item Clutch plate temperature Area1 Area2 Area3 Area4 0 50 100 150 200 250 300 350

Coefficient of friction u1 - - - - - - - - u2 - - - - - - - - u3 - - - - - - - - u4 - - - - - - - - u5 - - - - - - - -

In Table 4, frictional judder torque is calculated by selecting a value corresponding to the temperature of the clutch plate included in the control signal and the friction coefficient of the clutch disk. The values used in Table 4 are not values with physical quantities, but general constants, which are selected using experiential values based on test data. The specific value may vary depending on the vehicle type and the transmission.

The operation unit 102 selects the maximum value of the creep torque using the compensated clutch torque calculated in the above-described manner and transmits a new creep torque to the step S210 for feedback control (S250).

The calculated compensating clutch torque should be limited to less than a predetermined percentage (%) of the creep torque. This is because a sudden change in torque may cause discomfort or discomfort to the driver. The predetermined ratio may vary depending on the transmission and the vehicle design method. Therefore, when the calculated value of the compensating clutch torque exceeds a predetermined ratio of the creep torque, a value corresponding to a predetermined ratio becomes the value of the compensating clutch torque. The creep torque maximum value (Creep Torque Max) can be expressed by the following equation (4).

In Equation (4), the maximum value of the creep torque can be obtained by adding the value obtained by multiplying the creep torque by a predetermined ratio (%) to the creep torque. The "Cryptot * predetermined ratio (%)" portion corresponds to the maximum value (upper limit) of the calculated compensating clutch torque value.

The creep torque is updated to a value obtained by adding the compensating clutch torque calculated in the step S240 to the next step in a range not exceeding the maximum value of the creep torque, and at the same time, the creep torque included in the control signal is also updated.

The control unit 103 controls the clutch 20 using the torque value (final creep demand torque) finally received from the operation unit 102 (S260). The finally received torque value is the same as the value transmitted as the updated creep torque in the control signal collecting unit 101 to step S210.

In step S220, even if it is determined that it is not a judder-generated area, step S260 is immediately performed. In this case, a creep torque Old without adding a compensating clutch torque is used for controlling the clutch 20. [

Therefore, when a judder occurs, control is performed using the compensating clutch torque obtained through steps S220 and S250, thereby reducing judder occurrence and improving the shifting feeling at the time of oscillation and creep traveling. It also positively affects the durability of the transmission.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

10: Sensor
20: clutch
100: Creep torque control device
101: control signal collecting unit
102:
103:

Claims (9)

Collecting a control signal at the time of oscillation or creep of the vehicle;
Determining whether a judder generating region is present based on the control signal;
Calculating a compensation clutch torque when a judder occurs; and
And controlling the clutch based on the compensating clutch torque,
The control signal includes at least one or more information on the RPM of the engine and the input shaft, information on the torque of the engine and the clutch, information on the temperature of the clutch plate, information on the touch point, The clutch torque control method comprising: The method according to claim 1,
The step of verifying whether the judder occurrence region is
When the difference between the engine RPM and the input shaft RPM is equal to or less than the first RPM and equal to or greater than the second RPM, the judging portion determines that the judder occurs. The method according to claim 1,
After confirming whether it is the judder occurrence area
Further comprising the step of confirming the position of the gear lever when the judder occurs. The method according to claim 1,
The step of calculating the compensating clutch torque
Calculating a creep torque included in the control signal, and updating a creep torque included in the control signal by adding the creep torque and the compensating clutch torque, and the value of the compensating clutch torque is set to a predetermined Is limited to a ratio (%) or less. The method according to claim 1,
The step of calculating the compensating clutch torque
An area determining step of determining whether the area is a geometric judder area or a friction judder area;
And calculating a compensating clutch torque according to the determined judder area. 6. The method of claim 5,
The area determination step
And determining the clutch creep torque using slip RPM. 6. The method of claim 5,
The calculating step
And calculating, based on the touch point, the temperature of the clutch plate (Clutch Plate 1/2) in the case of the geometric judder region,
Wherein the friction force is calculated based on a temperature of the clutch plate (Clutch Plate 1/2) and a friction coefficient of the clutch disc in the friction judder region. A control signal collector for collecting a control signal at the time of traveling a creep;
An operation unit that receives the control signal to determine whether the control signal corresponds to a judder generating region and calculates a compensating clutch torque;
And a control unit for controlling the clutch in accordance with the compensating clutch torque,
The control signal includes at least one or more information on the RPM of the engine and the input shaft, information on the torque of the engine and the clutch, information on the temperature of the clutch disk, information on the touch point, And the clutch torque control unit is configured to control the clutch torque control unit. 9. The method of claim 8,
Wherein the calculating unit calculates the compensating clutch torque using the creep torque included in the control signal and updates the creep torque included in the control signal by adding the creep torque and the compensating clutch torque. Torque control device.

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