Patent ID: 11927153
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Chemical engineering (Chemistry)
Classification: CPC F  B  G | IPC B  F  G

Claim 0:
1. A diagnostic system for an evaporated fuel treatment system, the diagnostic system comprising:
a fuel tank configured to store liquid fuel;
a canister configured to adsorb evaporated fuel generated in the fuel tank to collect the evaporated fuel;
a vapor passage connecting the fuel tank with the canister;
a float valve disposed in the fuel tank and configured to move up and down in accordance with a change in level of liquid fuel to close and open an opening of the vapor passage adjacent to the fuel tank;
a remaining amount sensor disposed in the fuel tank and configured to detect a remaining amount of liquid fuel;
a pressure reducing mechanism configured to reduce a pressure in the vapor passage; and
a diagnostic device configured to determine whether there is a blockage of the vapor passage, wherein:
the diagnostic device is configured to execute
a first acquisition process of acquiring a remaining amount of liquid fuel in the fuel tank when an ignition switch of a vehicle on which the fuel tank is mounted turns off, as an end remaining amount,
a determination process of, after the first acquisition process, determining whether there is a blockage of the vapor passage by reducing a pressure in the vapor passage with the use of the pressure reducing mechanism when the end remaining amount is smaller than a predetermined prescribed value while the ignition switch of the vehicle is off,
a second acquisition process of, after the determination process, acquiring a remaining amount of liquid fuel in the fuel tank when the ignition switch of the vehicle turns on, as a start remaining amount, and
an invalidation process of invalidating a determination result that a blockage is present in the vapor passage in the determination process when the start remaining amount is larger than or equal to a predetermined set value.