Fuel pump with reduced seal wear for a direct injection system

A fuel pump for a direct injection system comprising:

• at least one pumping chamber;
• a piston slidingly mounted inside the pumping chamber to cyclically vary a volume of the pumping chamber;
• an intake duct connected to the pumping chamber and regulated by an inlet valve;
• a delivery duct connected to the pumping chamber and regulated by a one-way valve allowing only outgoing-fuel flow from the pumping chamber;
• a seat arranged below the pumping chamber around a lower portion of the piston;
• an annular seal housed in the seat and preventing fuel leakage along a side wall of the piston;
• an annular element delimiting, on an upper side thereof, the seat housing the seal such that an axial dimension of the seat is not greater than an axial dimension of the seal to prevent the seal from axially “shaking” inside the seat as a consequence of cyclic axial movement of the piston;
• and
• an annular cap that is welded to a lower portion of a main body of the filet pump and the seat housing the seal is delimited laterally and at a bottom by corresponding walls of the annular cap and at a top by the annular element, wherein the annular element has a flat upper edge that rests against an upper side of the annular cap, a lateral edge that rests against a side wall of the annular cap, and a lower edge that protrudes perpendicularly from the side wall of the annular cap and has a U-shaped cross-section so as to provide a certain elastic deformability.