High pressure fuel pump 10 for internal combustion engine, having a body 12B provided with a pumping bore 22 extending along a pumping axis Z1 and a piston 26 reciprocating therein and defining a compression chamber 24, an inlet conduit 28 controlled by an inlet valve 30 and an outlet conduit 18 controlled by an outlet valve 32 opening into said chamber, the pump further comprising a pressure relief valve or PRV 34 only opening to enable a return flow from the outlet conduit back to the compression chamber, wherein the PRV is arranged in an elongated PRV chamber (36, fig. 3) parallel with and offset from the pumping bore, sealed at an end by a plug member (44, fig. 3). The plug member, preferably press-fitted into the PRV chamber, may also serve as the valve seat (56, fig. 4) and be provided with internal conduits, i.e. an axial and a transverse drilling (54, 58, Fig. 4), and with a hollow such as an annular groove (52, fig. 4) on its peripheral face (46, fig. 4), the transverse drilling opening into said groove. Thus, fluid communication between the PRV inlet channel (38, fig. 3) and the compression chamber is ensured.
展开▼
