T-S curve correction method for clutch system

Abstract

A T-S curve correction method for a clutch system may include: detecting differences between actual positions of a clutch in first and second torque regions and a position on a T-S curve; determining whether the difference between the actual position in the first torque region and the position on the T-S curve is equal to or more than a first reference value; determining whether the difference between the actual position in the second torque region and the position on the T-S curve is equal to or less than a third reference value, when the difference of the actual position in the first torque region is equal to or more than the first reference value; and correcting the slope of the T-S curve in the increasing direction, when the difference of the actual position in the second torque region is equal to or less than the third reference value.

Claims

1. A T-S (Torque-Stroke) curve correction method for a clutch system, comprising: detecting, by a controller, differences between actual positions of a clutch in first and second torque regions and a position on a T-S curve; determining, by the controller, whether the difference between the actual position in the first torque region and the position on the T-S curve is equal to or more than a first reference value; determining, by the controller, whether the difference between the actual position in the second torque region and the position on the T-S curve is equal to or less than a third reference value, when the difference between the actual position in the first torque region and the position on the T-S curve is equal to or more than the first reference value; correcting, by the controller, a slope of the T-S curve to be increased from a current slope of the T-S curve with a predetermined amount, when the difference between the actual position in the second torque region and the position on the T-S curve is equal to or less than the third reference value; and controlling, by the controller, a stroke of an actuator, based on the T-S curve with the corrected slope so that the clutch transmits a target torque from an engine, the actuator changing a position of the clutch, wherein the first torque region is a preset torque region in which the clutch transmits a torque less than a predetermined torque, and the second torque region is a preset torque region in which the clutch transmits a torque equal to or higher than the predetermined torque.

2. The T-S curve correction method of claim 1, further comprising: determining, by the controller, whether the difference between the actual position in the first torque region and the position on the T-S curve is equal to or less than a second reference value, when the difference between the actual position in the first torque region and the position on the T-S curve is less than the first reference value; determining, by the controller, whether the difference between the actual position in the second torque region and the position on the T-S curve is equal to or more than a fourth reference value, when the difference between the actual position in the first torque region and the position on the T-S curve is equal to or less than the second reference value; and correcting, by the controller, the slope of the T-S curve to be decreased from the current slope of the T-S curve with a predetermined amount when the difference between the actual position in the second torque region and the position on the T-S curve is equal to or more than the fourth reference value.

3. The T-S curve correction method of claim 1, wherein a second reference value is additionally used as a reference value for comparing the actual position in the first torque region to the position on the T-S curve, in addition to the first reference value.

4. The T-S curve correction method of claim 3, wherein the first and second reference values are set to the same value in the first torque region.

5. The T-S curve correction method of claim 1, wherein a fourth reference value is additionally used as a reference value for comparing the actual position in the second torque region to the position on the T-S curve, in addition to the third reference value.

6. The T-S curve correction method of claim 5, wherein the third and fourth reference values are set to the same value in the second torque region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagram illustrating a schematic configuration of a general DCT control apparatus.

(2) FIG. 2 is a flowchart illustrating a T-S curve correction method for a clutch system in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

(3) Hereafter, a T-S (Torque-Stroke) curve correction method for a clutch system in accordance with an embodiment of the invention will be described in detail with reference to the accompanying drawings.

(4) Through the specification, it should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or sizes of components for descriptive convenience and clarity only. Furthermore, the terms as used herein are defined by taking functions of the invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosures set forth herein.

(5) The present embodiment provides a method for determining differences between actual positions at low and high torques and a position on a T-S curve indicating the relation between transmittable torque and clutch position, and correcting the slope of the T-S curve in the increasing or decreasing direction in a dry clutch system which controls the position of a clutch using a motor and has an incorrect temperature characteristic because a clutch for transmitting or blocking power in a transmission for transmitting power of a vehicle engine is operated in an air-cooling manner.

(6) For reference, a wet transmission increases the position of a solenoid, and converts the position into clutch torque. However, since a dry transmission (for example, DCT) mainly uses a motor, the dry transmission increases the position (stroke) of the motor and converts the position into clutch torque.

(7) That is, while the position s (stroke) of the motor is increased, a clutch disk is pushed to generate a force F. The force F is multiplied by a friction coefficient , thereby defining a torque t applied to the clutch disk, that is, a T-S curve characteristic.

(8) Thus, in order to satisfy a target clutch torque, a target motor position is calculated and converted into a T-S curve. Then, a TCU (Transmission Control Unit) controls the target motor position to raise the clutch torque.

(9) FIG. 2 is a flowchart illustrating a T-S curve correction method for a clutch system in accordance with an embodiment of the present invention.

(10) As illustrated in FIGS. 1 and 2, the controller 130 for controlling the DCT determines differences between actual positions at low and high torques and a position on a T-S curve indicating the relation between transmittable torque and clutch position, and corrects the slope of the T-S curve in the increasing or decreasing direction.

(11) Referring to FIG. 2, the controller 130 detects a difference between an actual position of the clutch in a preset low-torque region (that is, first torque region) and a position on the T-S curve, at step S101.

(12) Furthermore, the controller 130 detects a difference between an actual position of the clutch in a preset high-torque region (that is, second torque region) and a position on the T-S curve, at step S102.

(13) The low-torque region (first torque region) may be differently set depending on embodiments. Furthermore, the high-torque region (the second torque region) may be set to a relative concept of the low-torque region (the first torque region).

(14) The low-torque region (first torque region) and the high-torque region (second torque region) may be set by dividing the entire torque region into two parts, or set at both sides of an intermediate region (normal region) of the entire torque region.

(15) For convenience of description, the present embodiment is based on the supposition that the entire torque region is divided into two parts, that is, the low-torque region (first torque region) and the high-torque region (second torque region).

(16) When the difference between the actual position of the clutch in the low-torque region (first torque region) and the position on the T-S curve is detected at step S101, the controller 130 determines whether the difference of the position in the low-torque region (first torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or more than a first reference value, at step S103.

(17) When the difference of the position in the low-torque region (first torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or more than the first reference value (example of step S103), the controller 130 determines whether the difference of the position in the high-torque region (second torque region), that is, the difference between the actual position and the position on the T-S curve is equal to less than a third reference value, at step S104.

(18) When the difference of the position in the high-torque region (second torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or less than the third reference value (example of step S104), the controller 130 corrects the slope of the T-S curve in the increasing direction, at step S105.

(19) When the difference of the position in the low-torque region (first torque region), that is, the difference between the actual position and the position on the T-S curve is less than the first reference value (No at step S103), the controller 130 determines whether the difference of the position in the low-torque region, that is, the difference between the actual position and the position on the T-S curve is equal to less than a second reference value, at step S106.

(20) The first and second reference values are reference values used for comparing the actual position in the low-torque region (first torque region) to the position on the T-S curve. Depending on embodiments, the first and second reference values may be set to the same value.

(21) Then, when the difference of the position in the low-torque region (first torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or less than the second reference value (example of step S106), the controller 130 determines whether the difference of the position in the high-torque region (second torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or more than a fourth reference value, at step S107.

(22) When the difference of the position in the high-torque region (second torque region), that is, the difference between the actual position and the position on the T-S curve is equal to or more than the fourth reference value (example of step S107), the controller 130 corrects the slope of the T-S curve in the decreasing direction, at step S108.

(23) The third and fourth reference values are reference values used for comparing the actual position in the high-torque region (second torque region) to the position on the T-S curve. Depending on embodiments, the third and fourth reference values may be set to the same value.

(24) The T-S curve correction method in accordance with the present embodiment can determine differences between actual positions at low and high torques and positions on the T-S curve and correct the slope of the T-S curve, thereby preventing an occurrence of slip or gear shifting shock.

(25) Although preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as defined in the accompanying claims.