FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To prevent the cavitation erosion in a suction and overflow hole from occurring. SOLUTION: In a fuel injection pump, incoming and outgoing of fuel to at least one suction and overflow hole 8 formed in a pump plunger bush 3 are controlled with an upper side control edge 11 and a lower side control edge 12 of a pump plunger 4 reciprocating in the pump plunger bush 3, and an early stage control groove 10 is formed in the wall of the suction and overflow hole 8. The suction and overflow hole 8 is comprised of a minor diameter hole 81 having an opening surface 14 to peep through the inside of the pump plunger bush 3 at one end 81A and a major diameter hole 82 to communicate to the other end 81B of the minor diameter hole 81. A bottom 10A of the early stage control groove 10 is extended inclining toward upwards in the direction apart from the opening surface 14. The inside surface of an communicating end of the major diameter hole 82 to the minor diameter hole 81 is formed to a spherical surface 82C. COPYRIGHT: (C)2005,JPO&NCIPI