Blow molding device and blow molding method for plastic fuel tank

The invention relates to a blow molding device and a blow molding method for a plastic fuel tank. The blow molding device is symmetrically provided with two sets of profile blank extrusion devices; each set of profile blank extrusion device comprises six extruders, six hoppers, six melt metering pumps, a composite distributor and a servo plane die head; the melt metering pumps are respectively arranged at the outlets of the six extruders, the melts pumped by the melt metering pumps are fused together through the composite distributor, and the fused melt is fed into the servo plane die head and extruded into left and right plane profile blanks; the left and right plane profile blanks are respectively clamped by a right half die of a left oil tank to close, and a pre-formed shim plate is clamped in the middle; a blowing needle pierces the cavities of the profile blanks to perform pre-blowing, so that the profile blanks are outwards expanded and jointed to the inner wall of the die cavity; the right half die of the left oil tank is opened, the pre-formed shim plate is moved out, and a built-in component is stuck to the inner wall of the die cavity; and the right half die of the left oil tank is newly closed, the left and right profile blanks are stuck to form an oil tank, and the cavity of the oil tank is subjected to high-pressure blowing so that the oil tank is formed. The fueltank manufactured by the method has the advantages that: leakage is reduced, and efficiency and quality of the finished product are improved.