Abstract: In a fuel tank system, a control unit diagnoses a failure of a fuel storage unit and a processing unit. The fuel storage unit includes a vapor passage through which a fuel tank and a sealing valve are communicated with each other, a first pressure detection unit, and a second pressure detection unit disposed at a position different from the first pressure detection unit. The control unit specifies a presence or an absence of a clogging of the vapor passage based on a first pressure value detected by the first pressure detection unit and a second pressure value detected by the second pressure detection unit when the pressure in the fuel tank is changed by the pressure generation unit in a condition that the sealing valve is controlled to be opened.

Abstract: A fuel tank system includes a fuel storage unit, a processing unit, and a control unit. The control unit performs a first failure diagnosis of diagnosing a failure of the fuel storage unit in a state where the sealing valve is closed. When the control unit diagnoses that the fuel storage unit is normal, the control unit performs a second failure diagnosis of diagnosing a failure of a purge valve and a bypass valve by causing a pressure generation unit to generate pressure in a state where the sealing valve is closed. When there is a possibility that the purge valve and the bypass valve are in closed-sticking, the control unit performs a third failure diagnosis of specifying a failure in any one of closed-sticking of the purge valve and closed-sticking of the bypass valve by opening the sealing valve.

Abstract: A control unit diagnoses a failure of a fuel storage unit that seals a fuel tank and a processing unit that processes fuel evaporative gas in the fuel tank. A first pressure detection unit of the fuel storage unit detects the pressure of the fuel tank. A second pressure detection unit of the fuel storage unit is disposed at a position different from the first pressure detection unit, and detects the pressure of the fuel tank. The control unit specifies a failure portion of the fuel storage unit and the processing unit based on a change in either one or both of a first pressure value detected by the first pressure detection unit and a second pressure value detected by the second pressure detection unit when the pressure of the fuel tank is changed.

Abstract: A fuel tank system includes a fuel storage unit, a processing unit, and a control unit. The control unit performs a first failure diagnosis of diagnosing a failure of the fuel storage unit in a state where the sealing valve is closed. When the control unit diagnoses that the fuel storage unit is normal, the control unit performs a second failure diagnosis of diagnosing a failure of a purge valve and a bypass valve by causing a pressure generation unit to generate pressure in a state where the sealing valve is closed. When there is a possibility that the purge valve and the bypass valve are in closed-sticking, the control unit performs a third failure diagnosis of specifying a failure in any one of closed-sticking of the purge valve and closed-sticking of the bypass valve by opening the sealing valve.

Abstract: In a fuel tank system, a control unit diagnoses a failure of a fuel storage unit and a processing unit. The fuel storage unit includes a vapor passage through which a fuel tank and a sealing valve are communicated with each other, a first pressure detection unit, and a second pressure detection unit disposed at a position different from the first pressure detection unit. The control unit specifies a presence or an absence of a clogging of the vapor passage based on a first pressure value detected by the first pressure detection unit and a second pressure value detected by the second pressure detection unit when the pressure in the fuel tank is changed by the pressure generation unit in a condition that the sealing valve is controlled to be opened.