FUEL SYSTEM FOR IMPROVEMENT OF FUEL FILLING CHARACTERISTIC HAVING NEGATIVE PRESSURE TANK FORMED TO OUTLET SIDE OF AIR FILTER FORMED TO CANISTER

摘要

PURPOSE: A fuel system for improvement of a fuel filling characteristic is provided to prevent shut-off, spit back, and over flow in filling fuel by forming a negative pressure tank to the outlet side of an air filter formed to a canister and facilitating the filling of fuel into a fuel tank. CONSTITUTION: In a fuel system for improvement of a fuel filling characteristic, an ORVR(On-board Refueling Vapor Recovery) valve(4) is installed to an upper side of a fuel tank(1) and evaporation gas exhausted through the ORVR valve is collected by a canister(6) and is supplied to an engine by the opening and shutting action of a purge control valve(7). A fuel filling pipe(3) is formed to another side of the fuel tank. The fuel system for improvement of the fuel filling characteristic comprises an air filter(10) exhausting just air in the evaporation gas collected to the canister; a negative pressure tank(11) installed to the output side of the air filter; a pressure control valve(12) automatically opening if the negative pressure of the negative pressure tank falls under a predetermined value and making the negative pressure tank filled with negative pressure by the suction-negative pressure produced from the surge tank side during operation; a first solenoid valve(13) installed to a connection part between the air filter and the negative pressure tank and opened and shut according to the control of an ECU(Electronic Control Unit,9); a pressure sensor(8) sensing the pressure state in the fuel tank; and the ECU improving the fuel filling characteristic by detecting the filling state of fuel according to the pressure information sensed from the pressure sensor, opening the first solenoid valve during filling of fuel, and making the evaporation gas in the fuel tank exhausted to the canister side by the negative pressure of the negative pressure tank.