| 摘要 |
A fuel pump in which fuel injection conditions are not deteriorated by a discharge of vapor to the engine side and that achieves a large fuel suction height and a short fuel suction time. An air discharge opening and an air discharge valve mechanism are provided in a downstream channel including the end of the pump channel. The air discharge opening has a channel area s satisfying s >= 0.07 mm^2. The air discharge valve mechanism is opened in the start of a pump to discharge sucked air, and the mechanism is closed upon the start of fuel pressurization, preventing the fuel from being discharged to the outside of the pump channel. Further, a vapor discharge opening and a vapor discharge valve mechanism are provided in that part of the pump channel which is between the air discharge opening and an inlet section of the pump channel. The vapor discharge valve mechanism is closed in the start of the pump, preventing negative pressure at a fuel suction opening from being reduced, and the mechanism is opened in the start of fuel pressurization, discharging fuel containing vapor to the outside of the pump channel.
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