A nozzle body of a fuel injector includes a proximal end, a distal end spaced apart from the proximal end, and at least one spray hole positioned at the distal end. The at least one spray hole includes an inlet having a first cross-sectional shape and an outlet having a second cross-sectional shape different from the first cross-sectional shape. In other embodiments, the nozzle body has a first row of spray holes and a second row of spray holes, and a cross-sectional shape of spray holes in the first row is different from the cross-sectional shape of spray holes in the second row.

A fuel injector in an engine system includes a nozzle having a plurality of spray orifices, and forming a check seat and a sac. A nozzle check is movable in the nozzle between a closed position in contact with the check seat, and an open position. The nozzle check includes a tip having a flat nib and an outer tip surface profiled to define a seating line for sealing with the check seat. The arrangement is associated with fuel flow patterns having reduced risk of cavitation damage via biasing high-velocity flows of fuel away from an outer sac wall. Related apparatus and methodology is also disclosed.

A plurality of injection holes include at least one flat injection hole while an outlet opening of the at least one flat injection hole has a long axis and a short axis, and the at least one flat injection hole includes at least one specific flat injection hole. The specific flat injection hole has an injection hole axis that connects between a center of an inlet opening and a center of the outlet opening, and the long axis of the outlet opening is perpendicular to a plane which includes the injection hole axis and is parallel with the valve axis. An inner wall of the outlet opening has two planar portions which are opposed to each other while the long axis is interposed between the planar portions.

A fuel injector nozzle (9) is disclosed. The nozzle (9) comprises a nozzle tip (9) comprising an inner surface (39) and an outer surface (41). The nozzle (9) further comprises a number of fuel injection holes (11) each forming an inlet opening (31) at the inner surface (39) and an outlet opening (32) at the outer surface (41). At least one fuel injection hole (11) has a geometrical centre line (c1) being curved along at least a first portion (p1) of the at least one fuel injection hole (11). The radius of curvature (r1) of the geometrical centre line (c1) increases as seen in a direction (d1) from the inlet opening (31) towards the outlet opening (32). The radius of curvature (r1) increases continuously along the full first portion (p1) of the at least one fuel injection hole (11) as seen in the direction (d1) from the inlet opening (31) towards the outlet opening (32). A fuel injector (1), an internal combustion engine (40), and a vehicle (2) are also disclosed.