Fuel tank system

1. A fuel tank system for a vehicle having an internal combustion engine, the fuel tank system comprising:

a fuel storage unit having a sealing valve and configured to seal a fuel tank that stores fuel;

a processing unit configured to process fuel evaporative gas in the fuel tank; and

a control unit configured to diagnose a failure of the fuel storage unit and the processing unit,

wherein the fuel storage unit includes

a first pressure detection unit configured to detect a pressure of the fuel tank, and

a second pressure detection unit disposed at a position different from the first pressure detection unit and configured to detect a pressure of the fuel tank, and

a vapor passage through which the fuel tank and the sealing valve are communicated with each other,

wherein the processing unit includes

a purge passage through which the sealing valve and an intake passage of the internal combustion engine are communicated with each other,

a first on-off valve configured to be opened and closed between the intake passage and the purge passage,

a canister connected to the purge passage between the sealing valve and the first on-off valve and configured to adsorb fuel evaporative gas in the fuel tank, and

a pressure generation unit connected to the canister and configured to generate pressure, and

wherein the control unit is configured to specify 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.

2. The fuel tank system according to claim 1 ,

wherein control unit is configured to

record a presence or an absence of a sticking of the second pressure detection unit, during an ignition switch of the vehicle is switched on,

specify that the vapor passage is clogged, when the first pressure value is changed, the second pressure value is unchanged, and there is no sticking in the second pressure detection unit, after a predetermined time period has passed in a condition that the sealing valve is opened and the pressure in the fuel tank is changed by the pressure generation unit.

3. The fuel tank system according to claim 1 ,

wherein the control unit is configured to perform

a pressure control for lowering the pressure in the fuel tank, and

a fuel supply control for allowing a fuel supply port to be opened, the fuel supply port being a supply port of the fuel tank, and

wherein the control unit is configured to prohibit the pressure control and the fuel supply control, when the vapor passage is specified as being clogged.

4. The fuel tank system according to claim 1 , wherein the first pressure detecting unit comprises an absolute pressure sensor configured to detect an absolute pressure in the fuel tank, and

wherein the second pressure detecting unit comprises a differential pressure sensor configured to detect the pressure in the fuel tank based on an atmospheric pressure.

5. The fuel tank system according to claim 1 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

6. The fuel tank system according to claim 2 ,

wherein the control unit is configured to perform

a pressure control for lowering the pressure in the fuel tank, and

a fuel supply control for allowing a fuel supply port to be opened, the fuel supply port being a supply port of the fuel tank, and

wherein the control unit is configured to prohibit the pressure control and the fuel supply control, when the vapor passage is specified as being clogged.

7. The fuel tank system according to claim 2 , wherein the first pressure detecting unit comprises an absolute pressure sensor configured to detect an absolute pressure in the fuel tank, and

wherein the second pressure detecting unit comprises a differential pressure sensor configured to detect the pressure in the fuel tank based on an atmospheric pressure.

8. The fuel tank system according to claim 3 , wherein the first pressure detecting unit comprises an absolute pressure sensor configured to detect an absolute pressure in the fuel tank, and

wherein the second pressure detecting unit comprises a differential pressure sensor configured to detect the pressure in the fuel tank based on an atmospheric pressure.

9. The fuel tank system according to claim 6 , wherein the first pressure detecting unit comprises an absolute pressure sensor configured to detect an absolute pressure in the fuel tank, and

wherein the second pressure detecting unit comprises a differential pressure sensor configured to detect the pressure in the fuel tank based on an atmospheric pressure.

10. The fuel tank system according to claim 2 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

11. The fuel tank system according to claim 3 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

12. The fuel tank system according to claim 4 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

13. The fuel tank system according to claim 6 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

14. The fuel tank system according to claim 7 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

15. The fuel tank system according to claim 8 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.

16. The fuel tank system according to claim 9 , wherein the first pressure detecting unit is provided to the vapor passage, and

wherein the second pressure detecting unit is provided to the fuel tank.