To provide a flexible tube usable for pulsing reduction of a fuel pipe system and a quick connector by restraining vibration derived by standing wave which occurs in a fuel delivery pipe in connection with fuel injection of an engine for electronic fuel injection type automobile vehicle, thereby preventing a vehicle from causing abnormal sound which is transmitted from a vehicle body to a vehicular inside.
A pulsing reduction system provides a smaller diameter tube portion which includes inner diameter smaller than that of a main fuel pipe inside of a resin tube or in the vicinity of a connecting portion and establishes length of the smaller diameter tube portion to that of 10 to 50 times as long as the inner diameter of it. Cross section area of a flow passage in the smaller diameter tube portion is established to 5 to 40% of cross section area of flow passage in the main fuel pipe. It reduces, by the smaller diameter tube portion, the standing wave occurring in the fuel delivery pipe. If the smaller diameter tube portion is formed inside the flexible tube and the quick connector, the system is capable of being utilized in the pulsing reduction.
TSUCHIYA HIKARI
HAYASHI KOICHI
OGATA TETSUO
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