Method for learning touch point of dual clutch transmission

A method for learning a touch point of a clutch in a Dual Clutch Transmission (DCT) vehicle, comprising:

• a synchronization determination step in which a controller determines whether a difference between speed of a drive input shaft and speed of a non-drive input shaft is less than a reference value when a gear is engaged with the drive input shaft;
• a drive shaft slip inducement step in which the controller induces a clutch of the drive shaft to slip by partially releasing torque of the clutch of the drive shaft when it is determined in the synchronization determination step that the difference between the speed of the drive input shaft and the speed of the non-drive input shaft is less than the reference value;
• a non-drive shaft torque application step in which the controller applies torque to a clutch of the non-drive shaft so as to make the speed of the non-drive input shaft follow engine speed;
• and
• a touch point learning step in which, while the speed of the non-drive input shaft follows the engine speed in the non-drive shaft torque application step, the controller searches for a certain point at which the speed of the non-drive input shaft changes and differs from the speed of the drive input shaft, and learns the point as the touch point of the clutch of the non-drive shaft.