Vapor lock preventing mechanism in motor-driven fuel pump

摘要

A multi-stage motor-driven fuel pump including a motor section provided with an electric motor and a pump section to be driven by the electric motor, the pump section having a plurality of pump chambers partitioned by intermediate plates and communicated with each other by a fuel communication hole formed through each of the intermediate plates. A ratio of a sectional area of the fuel communication hole of any one of the intermediate plates between adjacent ones of the pump chambers to a sectional area of the pump chamber on a lower pressure side is set in a predetermined range such that a gradient of fuel pressure increase in the pump section is increased to early prevent vapor lock.