FUEL PUMP FOR A DIRECT INJECTION SYSTEM WITH A BETTER HYDRAULIC SEALING OF THE INTAKE VALVE

摘要

A fuel pump for a direct injection system having: a pumping chamber; a piston, which is mounted in a sliding manner on the inside of the pumping chamber; an intake channel, which originates from a wall of the pumping chamber and has a housing portion; an intake valve, which is inserted into the housing portion of the intake channel; and a locking ring nut with an annular shape, which is threaded and is screwed into the housing portion of the intake channel so as to strike against the intake valve; the housing portion has an annular abutment, which reduces the diameter of the housing portion and against which the intake valve strikes; the locking ring nut is screwed into the housing portion with a tightening force that is sufficient to determine a plastic deformation of the annular abutment against the intake valve.

主权项

1. A fuel pump (4) for a direct injection system (1) provided with a common rail (3); the fuel pump (4) comprises:
a pumping chamber (14) defined in a main body (12); a piston (15), which is mounted in a sliding manner on the inside of the pumping chamber (14) so as to cyclically vary the volume of the pumping chamber (14); an intake channel (17), which originates from a wall of the pumping chamber (14) and has a housing portion (28), which is arranged in the area of the pumping chamber (14); an intake valve (18), which is inserted into the housing portion (28) of the intake channel (17); a delivery channel (19), which originates from a wall of the pumping chamber (14); a delivery valve (20), which is arranged along the delivery channel (19) in the area of the pumping chamber (14); a locking ring nut (30) with an annular shape, which is threaded and is screwed into the housing portion (28) of the intake channel (17) so as to strike against the intake valve (18); wherein the housing portion (28) of the intake channel (17) has an annular abutment (29), which reduces the diameter of the housing portion (28) and against which the intake valve (18) strikes; the fuel pump (4) is characterized in that: the intake valve (18) is made of a metal material having a greater hardness than the metal material of which the annular abutment (29) is made; and the locking ring nut (30) is screwed into the housing portion (28) of the intake channel (17) with a tightening force that is sufficient to determine a plastic deformation of the annular abutment (29) against the intake valve (18).