Fuel cell control system and related method

A fuel cell control system 1 includes a cooling liquid inlet temperature sensor 16 and a cooling liquid outlet temperature for detecting an operating temperature of a fuel cell stack 11A, a radiator 14 by which the operating temperature of the fuel cell stack 11A is regulated, and a control box 19 operative to set a fundamental target operating temperature, which forms an operating temperature to be a target for the fuel cell stack 11A to operate, to either an appropriate operating temperature range on a high temperature side or an appropriate operating temperature range on a low temperature side, which maximizes a system efficiency of the fuel cell system on a high temperature side, to control a bypass rate of the radiator 14 through a three-way valve 15 so as to allow the operating temperature of the fuel cell stack 11A to approach to the fundamental target operating temperature.