Fuel cell stack including ejector and blower for anode recirculation and method for controlling the same

A method for controlling a fuel cell system for vehicles which comprises a stack comprising a plurality of unit cells for generating electrical energy by electrochemical reaction of a fuel and an oxidizing agent, a blower for recirculating a gas exhausted from the stack so as to supply the gas back to the stack, and an ejector for recirculating the gas exhausted from the stack, receiving hydrogen so as to mix the hydrogen to the recirculated gas, and supplying a mixture to the stack, the method comprising:

• detecting a driving condition of the vehicle;
• calculating a recirculated hydrogen amount by using the driving condition of the vehicle and a performance map of the blower and a performance map of the ejector;
• calculating a stoichiometric ratio (SR) of the hydrogen in the stack;
• comparing the SR of the hydrogen in the stack with a value;
• and
• increasing the recirculated hydrogen amount if the SR of the hydrogen in the stack is smaller than the value,
• wherein the performance map of the blower stores a first recirculated hydrogen amount based on a pressure difference between an inlet and an outlet of the stack and a blower RPM, and the performance map of the ejector stores a second recirculated hydrogen amount based on the pressure difference between the inlet and the outlet of the stack and a hydrogen amount supplied to the ejector.