A method for purging a fuel tank includes providing a three-way valve connected to the fuel tank via a first purging line, connected to a second purging line opening into a suction duct and connected to a third purging line opening into an adsorption container. A first path can be released in the three-way valve, based on the pressure inside the fuel tank exceeding a first predetermined opening pressure inside the fuel tank and the engine being in operation, such that the fuel vapors are caused to be purge out of the fuel tank into the suction duct. A second path can also be released in the three-way valve, based on the pressure inside the fuel tank exceeding a second predetermined opening pressure inside the fuel tank and the engine being not in operation, such that the fuel vapors are caused to be purged out of the fuel tank into the adsorption container.