Distributor type fuel injection pump

摘要

In an inner-cam system fuel injection pump, two balance ports that are offset symmetrically relative to a distribution port in a circumferential direction to form a Y-shape are formed at a rotor. The opening ends of the balance ports and the opening end of the distribution port are positioned on the same plane that is perpendicular to the axis of the rotor. The offset angle theta by which the balance ports are offset in the circumferential direction relative to the axis of the distribution port, the opening area S1 of the distribution port and the opening area S2 of each of the balance ports are set to satisfy a relationship expressed as S1=|2xS2xcos theta |. The phase intervals of the fuel delivery passages and the phase interval of the two balance ports are set equal to each other. Seizure at the area where the rotor slides in contact with its supporting member is prevented effectively and stable injection characteristics are achieved by equalizing the residual pressures in the individual fuel delivery passages.