Patent ID: 8206131

Claim:
A fuel pump for pressurizing fuel and pumping the fuel to an accumulation chamber, the fuel pump comprising: a housing having a compression chamber and a first passage, the first passage being configured to communicate the compression chamber with the accumulation chamber; a plunger axially movable in the pump housing for pressurizing fuel in the compression chamber; a discharge valve provided in the first passage and configured to open to supply fuel from the compression chamber to the accumulation chamber in response to increase in pressure in the compression chamber; a second passage configured to communicate one passage portion, which is at a side of the accumulation chamber with respect to the discharge valve, with an other passage portion, which is at a side of the compression chamber with respect to the discharge valve, the second passage defining a valve seat midway therethrough; a valve element having a valve element portion configured to be seated on the valve seat and configured to allow fuel flow substantially only from the accumulation chamber to the compression chamber, and a cylindrical portion extending from the valve element portion substantially in an axial direction of the second passage, the cylindrical portion being smaller than the valve element portion in outside diameter, an outer circumferential periphery of the cylindrical portion defining a sliding portion configured to slide along an inner wall of the second passage, to guide lifting and seating of the valve element portion; and a biasing unit for biasing the valve element to seat the valve element on the valve seat, wherein the second passage has a throttle midway therethrough for restricting fuel flow from the accumulation chamber to the compression chamber, and the throttle is defined between a sidewall of the outer circumferential periphery of the cylindrical portion of the valve element and the inner wall of the second passage.