Method for finding a contact point of a clutch in a dual-clutch transmission

Abstract

A method for finding a contact point of a clutch in a dual-clutch transmission, comprising: (a) a step (S210) of checking whether a contact point search condition for a non-drive clutch (2) and a drive clutch (1) is satisfied or not; (b) if the search condition of step (a) is satisfied, a step (S240) of detecting a search point at which an absolute value of a difference between an acceleration value (IV) of an engine and an acceleration value (V) of the drive clutch (1) is greater than a threshold value after a torque (S220) of the non-drive clutch (2) has been applied to the engine; and wherein in step (b) the search for the contact point is terminated if the acceleration value of the engine does not change despite the application of the torque of the non-drive clutch (2) to the engine; and (c) a step of determining a position of the non-drive clutch corresponding to the search point as the contact point.

Description

General state of the art1. Technical field

[0001] The present invention relates to a method for searching for a contact point of a clutch of a dual-clutch transmission. 2. Description of the state of the art

[0002] In a transmission system where engine power is transmitted through a clutch, control is generally performed based on a TS (torque-stroke) characteristic diagram (hereinafter referred to as the "TS curve"), which indicates a change in clutch torque with respect to a clutch position (stroke). Therefore, to perform highly reliable control, the TS curve, which changes according to a control environment (clutch temperature, etc.), should be learned.

[0003] In the TS curve, a contact point serves as a control element and has an important significance as the starting point of the TS curve, which transmits the power of the engine to the clutch by bringing a clutch plate and an engine plate into contact with each other.

[0004] A dual clutch transmission is designed to learn the TS curve by periodically examining the contact point of the clutch shaft, which is not driven between two clutches.

[0005] In other words, since the dual-clutch transmission is equipped with a clutch that can automatically decouple a force by means of an actuator, and the contact point as the starting point of operation of the clutch changes when using a dry clutch, for example due to a change in temperature or wear of the clutch, a precise examination of the contact point is necessary to ensure the long-term functionality of the clutch.

[0006] The conventional search for the contact point was usually based on the speed change value of an idle shaft at the time when the clutch is operated after confirming the idle state of a non-drive shaft.

[0007] However, the dual-clutch transmission has the advantage of preparing for the next transmission by engaging a gear in advance with the clutch that is not currently driven. However, in a state where a gear is engaged in advance with the clutch, it is not possible to search for a contact point using the conventional method, and control quality cannot be guaranteed during the next transmission if the condition persists. Summary

[0008] One aspect of the present invention is to provide a method for searching a contact point of a clutch, and more particularly, to provide a method for searching a contact point of a clutch that enables searching a contact point using the clutch position of the non-drive shaft when the drive shaft is slip-controlled in the engaged state of the non-drive shaft.

[0009] It should be understood that the objects of the present invention are not limited to the above-mentioned object. Other objects of the present invention will become apparent to those skilled in the art from the following descriptions. Furthermore, it should be understood that the objects and advantages of the present invention may be realized by the means and combinations of the appended claims.

[0010] According to one aspect of the present invention, there is provided a method for searching a contact point of a clutch in a dual-clutch transmission, comprising: (a) a step of checking whether or not a contact point search condition for a non-drive clutch and a drive clutch is satisfied; (b) when the search condition of step (a) is satisfied, a step of detecting a search point at which an absolute value of a difference between an acceleration value of a motor and an acceleration value of the drive clutch is greater than a threshold value after a position value of the non-drive clutch is applied to the motor; and (c) a step of determining a position of the non-drive clutch corresponding to the search point as a contact point.

[0011] In step (c), the touch point can be determined by adding an offset compensation value corresponding to a torque of the motor to the position of the non-drive clutch corresponding to the search point.

[0012] In step (a), the touch point search condition may be satisfied when the non-drive clutch is engaged and the drive clutch is in a slip control state.

[0013] In step (b), the search for the touch point can be terminated if the acceleration value of the motor does not change despite the application of the position value of the non-drive clutch to the motor. Brief description of the drawings

[0014] Fig. 1 is a functional diagram for explaining a method for searching a contact point of a clutch of a dual-clutch transmission according to an embodiment of the present invention.

[0015] Fig.2 is a flowchart illustrating a method for searching the contact point of the clutch of the dual-clutch transmission according to the embodiment of the present invention. Detailed description

[0016] The above objects, features, and advantages will become apparent from the detailed description with reference to the accompanying drawings. Embodiments are described in sufficient detail to enable those skilled in the art to easily apply the technical idea of ​​the present disclosure. Detailed disclosures of well-known functions or configurations may be omitted in order not to unnecessarily obscure the gist of the present disclosure. Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout.

[0017] Fig.1 is a functional diagram for explaining a method for searching a contact point of a clutch of a dual-clutch transmission according to an embodiment of the present invention.

[0018] Clutches are divided into a drive clutch (Clutch 1), which receives power from the engine, and a non-drive clutch (Clutch 2), which is decoupled from the engine under normal driving conditions. In this case, the non-drive clutch rotates through the gear ratio according to the vehicle's speed, engaging the next anticipated gear ratio in advance.

[0019] To find the contact point for an engaged non-drive clutch shaft, the present invention proposes a novel method that utilizes slip variations of an engine and a drive shaft by applying a torque of the non-drive clutch to the engine when the drive clutch is actuated with a torque equal to a torque of the engine via a slip control of the drive clutch.

[0020] In other words: A speed ( I ), as in Fig. 1, increases as the idle non-drive clutch (clutch 2) engages. Furthermore, it can be observed that the torque ( II ) of the engine and the torque ( III ) of the drive clutch have a similar position value because the drive clutch (Clutch 1), which receives the power from the engine, is in the slip control state.

[0021] In a state where such search conditions are satisfied, that is, in a state where the driving clutch is slip-controlled and the non-driving clutch is engaged, when the torque (position value) of the non-driving clutch is applied to the engine, that is, when position values ​​of the non-driving clutch changing from the idle state to the engaged state are applied to the engine, the instantaneous change at an acceleration value ( IV ) of the engine. Furthermore, the drawings confirm that using the information from the changes induced in this way allows the contact point of the non-drive clutch to be located.

[0022] In other words: A position ( WE ) of the non-drive clutch can be determined as the contact point at the time when a difference between the engine acceleration value ( IV), which is generated by applying the position value of the non-drive clutch to the motor, and an acceleration value ( V ) of the drive clutch, which maintains a constant height in a slip control state, ie at the time when the absolute value of the difference between the engine acceleration value ( IV ) and the acceleration value ( V ) of the drive clutch 1, exceeds a threshold value (see vertical dashed line in Fig. 1).

[0023] To determine the contact point more accurately, the contact point is preferably compensated at this time by applying a contact point offset corresponding to the torque of the motor (marked as a horizontal dashed line in Fig. 1) is added.

[0024] Fig.2 is a flowchart illustrating a method for searching the contact point of the clutch of the dual-clutch transmission according to the embodiment of the present invention.

[0025] According to Fig. 2, the clutch contact point search method of the dual-clutch transmission according to the embodiment of the present invention includes a step S210 of checking whether the contact point search condition is satisfied or not, a step S220 of applying the position value of a non-drive clutch to the motor, a step S240 of detecting a search point, etc.

[0026] Step S210 of checking whether the condition for searching the contact point is satisfied or not can be performed in two separate processes of checking whether the drive clutch is slip-controlled and the non-drive clutch is engaged.

[0027] If it is determined that the touch point search condition is satisfied in step S210, step S220 of applying the position value of the non-driving clutch to the motor is performed. As previously explained, this is the process of generating a modified acceleration value of the motor by applying the position values ​​of the non-driving clutch changing from the neutral state to the engaged state to the motor.

[0028] When the position value of the non-drive clutch is applied to the motor in step S220 and thus the acceleration value of the motor changes in step S230, step S240 may be performed to detect a search point.

[0029] The search point is a point where the absolute value of the difference between the motor acceleration value and the drive clutch acceleration value exceeds a threshold (reference value). That is, the search point satisfies the relationship [|(motor acceleration value) – (drive clutch acceleration value)| > threshold].

[0030] A position of the non-drive clutch corresponding to the search point detected in step S240 of detecting a search point can be determined as the contact point of the non-drive clutch. Furthermore, a compensation step S250 can be included, in which the position of the non-drive clutch corresponding to the detected search point is compensated by adding a contact point offset corresponding to the torque of the motor. Preferably, in step S260, the contact point is determined more accurately by the compensation step S250.

[0031] Here, if it is determined that the condition in step S210 of checking whether the condition for searching the contact point is satisfied or not is not satisfied, that is, if the drive clutch is not slip-controlled or the non-drive clutch is not engaged, as shown in Fig. 1, the process of searching for a contact point for the drive coupling can be terminated.

[0032] In addition, the operation of searching for a touch point can be set to stop when the acceleration value of the motor does not change (S230), even though the position value of the non-drive clutch is applied to the motor (S220).

[0033] That is, meshing can occur when the position value of the clutch reaches a predetermined maximum value while the acceleration value of the motor remains unchanged despite the application of the position value of the non-drive clutch to the motor. Thus, in the present invention, the search for a touch point can be completed by an additional process as described above.

[0034] As stated above, the present invention provides the clutch touch point searching method in which the touch point is detected by applying the position value of the non-drive clutch to the motor when the drive shaft is slip controlled and the non-drive shaft is in the engaged state.

[0035] By increasing the probability of learning the touch point by searching for the non-drive clutch touch point, the reliability of a TS curve can be improved. Accordingly, it is possible to achieve various effects, such as maximizing the advantage of the dual-clutch transmission that rapid transmission during gear shifting can be achieved simply by changing the clutch torque by engaging the clutch with the transmission in advance.

[0036] According to the present invention described above, there is an advantage that the reliability of a TS curve can be improved because the probability of learning a clutch touch point increases both by searching the clutch touch point for an engaged non-drive shaft and in searching the clutch touch point.

[0037] Accordingly, it is possible to improve the advantage of the dual clutch transmission that, when changing gears, a quick transmission can be achieved simply by changing the clutch torque by engaging the clutch with the transmission in advance.

[0038] Those skilled in the art will recognize that the present invention can be variously substituted, modified and changed without departing from the technical spirit of the invention, and that the present invention is not limited to the embodiments described above and the accompanying drawings.

Claims

[1] Method for searching a contact point of a clutch in a dual-clutch transmission, comprising: (a) a step of checking whether a touch point search condition for a non-drive clutch and a drive clutch is satisfied or not; (b) if the search condition of step (a) is satisfied, a step of detecting a search point at which an absolute value of a difference between an acceleration value of a motor and an acceleration value of the drive clutch is greater than a threshold value after a position value of the non-drive clutch has been applied to the motor; and (c) a step of determining a position of the non-drive clutch corresponding to the search point as a contact point. [2] The method according to claim 1, wherein the contact point is determined in step (c) by adding an offset compensation value corresponding to a torque of the engine to the position of the non-drive clutch corresponding to the search point. [3] The method according to claim 1, wherein in step (a) the touch point search condition is satisfied when the non-drive clutch is engaged and the drive clutch is in a slip control state. [4] The method of claim 3, wherein in step (b) the search for the touch point is terminated when the acceleration value of the motor does not change despite the application of the position value of the non-drive clutch to the motor.

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