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.

Abstract: A controller has a leak determiner determining the presence or absence of an evaporative gas leak in a fuel evaporative gas emission suppressing device, based on a first pressure which is the pressure of a canister when a first predetermined period has elapsed in a state where a first opening/closing section and a second opening/closing section are closed, a third opening/closing section is opened, a fourth opening/closing section is closed, and a pressure generating section is operated; and a second pressure which is the pressure within the canister when, after a lapse of the first predetermined period, a second predetermined period has elapsed in a state where the third opening/closing section is closed.

Abstract: A controller has a leak determiner determining the presence or absence of an evaporative gas leak in a fuel evaporative gas emission suppressing device, based on a first pressure which is the pressure of a canister when a first predetermined period has elapsed in a state where a first opening/closing section and a second opening/closing section are closed, a third opening/closing section is opened, a fourth opening/closing section is closed, and a pressure generating section is operated; and a second pressure which is the pressure within the canister when, after a lapse of the first predetermined period, a second predetermined period has elapsed in a state where the third opening/closing section is closed.

Abstract: After an engine is started, pump monitoring is performed as follows: a canister is opened to the atmosphere; a negative pressure pump is activated; and abnormality of the negative pressure pump is evaluated on the basis of canister pressure Pc detected with a pressure sensor in an evaporative leakage check module, and after the pump monitoring is completed, a switching valve is closed so that the negative pressure pump communicates with the canister for purge any fuel evaporative gas into an intake passage of the engine, and whether or not leakage has occurred in a fuel evaporative gas emission suppressor is evaluated based on the canister pressure Pc.

Abstract: After an engine is started, pump monitoring is performed as follows: a canister is opened to the atmosphere; a negative pressure pump is activated; and abnormality of the negative pressure pump is evaluated on the basis of canister pressure Pc detected with a pressure sensor in an evaporative leakage check module, and after the pump monitoring is completed, a switching valve is closed so that the negative pressure pump communicates with the canister for purge any fuel evaporative gas into an intake passage of the engine, and whether or not leakage has occurred in a fuel evaporative gas emission suppressor is evaluated based on the canister pressure Pc.

Abstract: When a leak test for a purge pipe and a vapor pipe as targets is executed, a sealing valve that is being closed is opened while an open state of a bypass valve is kept prior to the execution of the leak test, fuel evaporative gas in a fuel tank is caused to flow out to a canister side to reduce a tank internal pressure Ptan to a valve opening guarantee determination value P0, and after the bypass valve is closed subsequently, the leak test is started.

Abstract: When a leak test for a purge pipe and a vapor pipe as targets is executed, a sealing valve that is being closed is opened while an open state of a bypass valve is kept prior to the execution of the leak test, fuel evaporative gas in a fuel tank is caused to flow out to a canister side to reduce a tank internal pressure Ptan to a valve opening guarantee determination value P0, and after the bypass valve is closed subsequently, the leak test is started.