Fuel-mixing prevention filler neck device

A fuel-mixing prevention filler neck device, comprising:

• a fuel dispensing gun insertion unit into which a fuel dispensing gun is received;
• a coupling unit communicating with a bottom of the fuel dispensing gun insertion unit, the coupling unit disposed on an exterior circumferential surface thereof with coupling protrusions to couple the slots in a filler pipe, having a coupling region which is opened one side of a lower portion of the coupling unit;
• and
• a misfueling prevention unit slidably moved toward the coupling region and coupled to the coupling unit,
• wherein the misfueling prevention unit is closed when a gasoline fuel dispensing gun is inserted and is opened when a diesel fuel dispensing gun is inserted,
• wherein the misfueling prevention unit includes:
• a housing introducing the fuel dispensing gun that passes through the coupling unit thereinto;
• sliding protrusions mounted in a lower portion of the housing to be slidable adjusted in a lateral direction, the sliding protrusions being laterally spaced apart and adjacent to each other;
• a spring horizontally coupling and elastically supporting the sliding protrusions;
• a stopper having an engaging groove in any one of the sliding protrusions;
• and
• a flapper hinge-coupled to a remaining sliding protrusions of the sliding protrusions, the flapper released from the engaging groove to open an opening in a lower end of the housing as a distance between the adjacent sliding protrusions increases when the diesel fuel dispensing gun is inserted.