Method for controlling a damper clutch

A method for controlling a damper clutch in a torque converter of a combustion engine using only a power of an engine, comprising:

• determining, by an electronic control unit (ECU) or a transmission control unit (TCU), whether the damper clutch is in a slip or lock-up state in a driving state of a vehicle;
• determining whether a condition of the vehicle is within a predetermined resonant range;
• determining whether a torque of the vehicle is within a predetermined resonant torque range;
• detecting, by a sensor, a subharmonic vibration when the damper clutch is in the slip or lock-up state, the condition of the vehicle is within the predetermined resonant range, and the torque of the vehicle is within the predetermined resonant torque range;
• and
• controlling, by the electronic control unit (ECU) or the transmission control unit (TCU), the damper clutch to slip or be open when the subharmonic vibration is larger than a predetermined value;
• wherein the damper clutch has a 2-stage stiffness structure by applying dual damper springs, and the resonant torque range is a predetermined range that includes a torque corresponding to a break point of stiffness of the damper clutch;
• and
• wherein the controlling of the damper clutch to slip or be open includes controlling the damper clutch to slip when the subharmonic vibration is larger than a predetermined first index value.