Sealed fuel tank system

A sealed fuel tank system comprising:

• a fuel tank of a vehicle equipped with an internal combustion engine;
• a canister configured to adsorb and desorb fuel evaporated inside the fuel tank;
• a vapor passage connecting the fuel tank and the canister;
• a purge passage connecting the canister and an intake passage of the internal combustion engine;
• a shut-off valve disposed in the vapor passage and configured to seal the fuel tank;
• a purge valve configured to open and close the purge passage;
• a tank pressure detection unit configured to detect internal pressure of the fuel tank;
• a lid door operation unit configured to unlock a lid door;
• a lid lock portion;
• a control unit implemented by at least one programmed processor and configured to control the purge valve, the shut-off valve, and the lid lock portion;
• and
• a pre-refueling operation unit,
• wherein the lid lock portion is configured to lock and unlock the lid door covering a fuel tank opening, and unlock the lid door when the lid door operation unit is operated by a user and the internal pressure of the fuel tank is less than or equal to a specified pressure, and
• wherein the pre-refueling operation unit is configured to open the shut-off valve to reduce the internal pressure of the fuel tank to less than or equal to the specified pressure when operated prior to operation of the lid door operation unit.