| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that per pressure increase control for pulling up a sealed fuel tank from excessive negative pressure to low negative pressure, when a seal valve is opened/closed in a case where a cabin is extremely silent, operation sound is transmitted to a crew member to cause deterioration of a noise characteristic.SOLUTION: A control unit 32, when pressure of a fuel tank 14 lowers predetermined negative pressure Pnear fuel saturation vapor pressure, and a cabin sound level is a threshold or more, operates a seal valve 28 to increase the pressure of the fuel tank 14 to a normal negative pressure area P-Phigher than the predetermined negative pressure P.SELECTED DRAWING: Figure 1 |
