Ebullient cooling device

An ebullient cooling device comprising:

• an internal combustion engine cooled by boiling a coolant flowing through a coolant passage formed within the internal combustion engine;
• a gas-liquid separator that is disposed between the internal combustion engine and an expander, and separates a coolant discharged from the internal combustion engine into a liquid-phase coolant and a gas-phase coolant;
• a condenser that is disposed on a downstream side of the expander, and cools the gas-phase coolant having passed through the expander so as to be changed into a liquid-phase coolant;
• a first passage that supplies the liquid-phase coolant from the condenser to the coolant passage formed within the internal combustion engine;
• a second passage that is branched from the first passage, and is connected to the gas-liquid separator;
• a control valve that controls a supply state of a liquid-phase coolant supplied to the gas-liquid separator from the condenser through the second passage;
• a temperature sensor that obtains a temperature value of the coolant flowing through the coolant passage;
• a pressure sensor that obtains a pressure value within the gas-liquid separator;
• and
• a controller that controls the control valve based on a temperature value obtained by the temperature sensor and on a pressure value obtained by the pressure sensor.