System and method for controlling engine clutch delivery torque of hybrid electric vehicle

A system for controlling engine clutch delivery torque of a hybrid electric vehicle, the system comprising:

• an engine clutch configured to control power transmission between an engine and a motor;
• an integrated starter-generator (ISG) configured to start the engine or to generate electric power by output of the engine;
• a transmission configured to change power applied to wheels;
• and
• a controller configured to control the engine, the motor, the ISG, and the engine clutch in a predetermined condition and to check their states under the predetermined condition,
• wherein the controller is configured to:
• determine whether a state of a transmission of the hybrid electric vehicle satisfies a learning condition of the engine clutch delivery torque;
• control speed of the engine to a predetermined engine target speed, and control speed of the motor to a predetermined motor target speed, wherein the predetermined engine target speed and the predetermined motor target speed are different from each other, when the learning condition of the engine clutch delivery torque is satisfied;
• detect a speed change and a torque change of the engine and the motor, respectively, while supplying a hydraulic pressure to the engine clutch;
• and
• operate the ISG, when the detected speed change of the engine is equal to or greater than a predetermined value, in order for the predetermined engine target speed to be maintained by compensating the speed change of the engine.