Patent ID: 6761547
Filing Date: 2004-07-13
Classification: F04C

Abstract:
A trochoid fuel pump comprising:a single pair of inner and outer gears, said outer gear including inner teeth, said inner gear including outer teeth being eccentrically arranged at an inner periphery of said outer gear, said inner gear engaging with said outer gear to define pump chambers between the teeth thereof for forming a pump, wherein volumes of said pump chambers are continuously increased and decreased to suck and discharge fuel while said pump chambers are moved in a rotation direction by rotation of both said gears, said pump includes two discharge ports through which the fuel is discharged, each of said discharge ports being arranged so that said pump chambers sequentially communicate with said discharge ports, phases of discharge pressure pulsations of the fuel discharged from said two discharge ports are shifted from each other by an almost half wavelength, the fuel discharged from said two discharge ports is merged, said discharge ports include an upstream side discharge port and a downstream side discharge port, a start position of said upstream side discharge port is located in a vicinity of an end of a pump chamber which becomes maximum in volume, an end position of said upstream side discharge port is located in a vicinity of an end of a pump chamber which is formed when both said gears move by half phase, and a start position of said downstream side discharge port is located in a vicinity of an end of a pump chamber next to the end position of said upstream side discharge port when both said gears move by half phase.