| 摘要 |
PROBLEM TO BE SOLVED: To provide a fuel pump, in which high efficiency is implemented, rising of fuel discharge pressure is expedited upon starting, and fluctuation in fuel discharge amount by vapor is small. SOLUTION: A vapor discharge port 62 makes a pump flow passage mutually communicate to an outer space of the fuel pump, that is, an inner space of a fuel tank. An angleθof a center of arrangement of the vapor discharge port is set to be positive pressure of approximately 15% or more and 30% or less of fuel discharge pressure. The angleθof the center of arrangement of the vapor discharge port is determined according to pump flow passage structure. By setting the angleθof the center of arrangement of the vapor discharge port, retention of vapor in the pump flow passage is prevented, lowering of efficiency of the fuel pump caused by forming of the vapor discharge port 62 is suppressed, and the rising of the fuel discharge pressure upon starting is expedited. COPYRIGHT: (C)2004,JPO
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