Fuel injector for internal combustion engines

A fuel injector (10) for internal combustion engines, the fuel injector comprising

• a nozzle body (12) having therein a blind hole (14), from which at least one injection opening (22) starts, and
• a nozzle needle (26;
• 26a to 26g), which is arranged in a longitudinally movable manner in the nozzle body (12) and which has, on a side facing the blind hole (14), a sealing surface (28), by which the nozzle needle (26;
• 26a to 26g) interacts with a seat surface (17) of the nozzle body (12) in order to control a fuel flow to the at least one injection opening (22), and the nozzle needle having a needle tip (34), which adjoins the sealing surface (28) in a direction of the blind hole (14) and which has a first edge (41) with a first diameter (D1) extending radially around a longitudinal axis (15), wherein a second edge (42) adjoins the first edge (41) in the direction of the blind hole bottom (20) and has a second diameter (D2) extending radially around the longitudinal axis (15), wherein, in a lowered position of the nozzle needle (26;
• 26a to 26g) forming a sealing seat (30), the second edge (42) is arranged below a lower inlet edge (44) of the injection opening (22) when viewed in a direction of the longitudinal axis (15), wherein, in a partially open position of the nozzle needle (26;
• 26a to 26g), the first edge (41) is arranged below an upper inlet edge (45) of the injection opening (22) when viewed in the direction of the longitudinal axis (15), and wherein, in a fully open position of the nozzle needle (26;
• 26a to 26g), the second edge (42) is arranged above the lower inlet edge (44) of the injection opening (22) when viewed in the direction of the longitudinal axis (15),
• wherein a diameter (D1) of the nozzle needle (26;
• 26a to 26g) in a region of the first edge (41) is greater than a diameter (D2) of the nozzle needle (26;
• 26a to 26g) in a region of the second edge (42), and wherein a distance (a) between the first and second edges (41, 42), when viewed in the direction of the longitudinal axis (15), corresponds to 0.4 times to 1.6 times a diameter (d) of the injection opening (22) in an inlet region (24) to the blind hole (14) in the non-rounded state of the inlet region (24).