Patent attributes
In pressure increasing control for raising a pressure within a sealed type fuel tank from an excessive negative pressure to a low negative pressure, an opening or closing operation of a sealing valve, when the interior of a vehicle is very quiet, may cause the working noise thereof to be transmitted to a passenger, thereby deteriorating the noise characteristic. When the pressure within a fuel tank is below a predetermined negative pressure near a saturated vapor pressure of the fuel and an interior noise level is equal to or greater than a threshold value, a controller may operate a sealing valve to thereby raise the pressure of the fuel tank to a normal negative pressure region which may be higher than the predetermined negative pressure.