Closed tank system

A control method for a closed tank system, the closed tank system comprising:

• a fuel tank that is adapted to store fuel to be supplied to an internal-combustion engine mounted on a vehicle;
• a canister that is connected via a communication passage to the fuel tank and adapted to adsorb evaporative fuel generated in the fuel tank;
• a fill-up limiting valve that is provided in a chamber of the fuel tank so as to be communicated with the communication passage and adapted to operate to close the communication passage by allowing a float to float on the fuel when a fuel level reaches a predetermined full tank liquid level;
• a shut-off valve that is provided on a downstream side of the fill-up limiting valve in the communication passage when seen from the fuel tank and adapted to operate to open or close the communication passage;
• a pressure sensor adapted to detect a tank internal pressure of the fuel tank;
• a tilt angle detector adapted to detect a tilt angle of the vehicle;
• a fuel remaining amount detector that is adapted to detect a remaining amount of fuel stored in the fuel tank;
• and
• a hardware processor having a control section and a determining section,
• wherein the control method comprises:
• determining, using the determining section, whether or not the internal-combustion engine is in operation;
• determining, using the determining section, whether or not the tank internal pressure detected by the pressure sensor exceeds a tank internal pressure threshold;
• determining, using the determining section, whether or not the remaining amount of fuel detected by the fuel remaining amount detector exceeds a fuel remaining amount threshold;
• determining, using the determining section, whether or not the tilt angle of the vehicle detected by the tilt angle detector exceeds a tilt angle threshold;
• and
• inhibiting, using the control section, control for allowing the shut-off valve to be opened when:
• it is determined that the internal-combustion engine is in operation;
• the tank internal pressure detected by the pressure sensor exceeds the tank internal pressure threshold;
• the remaining amount of fuel detected by the fuel remaining amount detector exceeds the fuel remaining amount threshold;
• and the tilt angle of the vehicle detected by the tilt angle detector is equal to or smaller than the tilt angle threshold.