Method and system for changing running mode when battery discharge of hybrid vehicle is limited

A system for changing a running mode when a battery discharge of a hybrid vehicle that is operated with a power of an engine and a drive motor is limited, the system comprising:

• an engine clutch to control a power transmission between the engine and the drive motor;
• a battery to supply electric power that is necessary to operate the drive motor and a starting motor that starts the engine;
• and
• a controller configured to control the engine, the starting motor, and the drive motor,
• wherein the controller is operated by a program, and the program includes a series of commands for executing a method of changing the running mode when the battery discharge of the hybrid vehicle is limited, comprising:
• detecting each state of the drive motor and the battery;
• determining whether the change to the running mode in which a need for an operation of the engine is requested when the drive motor operates and the battery discharge is limited;
• operating a starting motor first with available power of the battery when the change to the running mode is requested;
• and
• controlling the engine so that the starting motor may perform a charging operation for synchronization of an engine clutch, and for driving the drive motor with the available power of the battery when the engine has been started by the starting motor.