Fuel cell system, fuel cell mountable vehicle and method of controlling fuel cell system

A fuel cell system to be mounted on a fuel cell mountable vehicle, comprising:

• a fuel cell;
• a cooling liquid supply flow path for supplying cooling liquid to the fuel cell;
• a cooling liquid pump provided at the cooling liquid supply flow path;
• a radiator for cooling the cooling liquid;
• a first temperature sensor, provided at an outlet of the radiator, for measuring a temperature of the cooling liquid;
• an ambient temperature sensor;
• and
• a controller, wherein the controller is programmed to execute:
• estimating a temperature of the cooling liquid inside the cooling liquid supply flow path based on an ambient temperature measured by the ambient temperature sensor;
• before it is determined that a predetermined volume of the cooling liquid has flowed into the radiator, controlling operation of the cooling liquid pump to adjust a flow rate of the cooling liquid flowing inside the cooling liquid supply flow path based on the estimated temperature;
• determining, based on the flow rate of the cooling liquid flowing inside the cooling liquid supply flow path via the operation of the cooling liquid pump, that the predetermined volume of the cooling liquid has flowed into the radiator;
• after the determination, acquiring a temperature of the cooling liquid inside the cooling liquid supply flow path based on the temperature measured by the first temperature sensor;
• and
• controlling the operation of the cooling liquid pump to adjust the flow rate of the cooling liquid flowing inside the cooling liquid supply flow path based on the acquired temperature of the cooling liquid.