Fuel injector

A fuel injector, comprising:

• an upper housing portion that defines an inlet passage adapted to receive fuel, wherein the inlet passage includes:
• (i) an insert-receiving section that has an insert-receiving diameter;
• and
• (ii) a narrowed section that occurs after the insert-receiving section along a direction in which fuel is adapted to flow through the inlet passage and that has a narrowed diameter that is less than the insert-receiving diameter;
• a lower housing portion that defines an injector outlet adapted to dispense fuel;
• an electromagnetic coil assembly;
• a movable pintle that is:
• (i) biased to a closed position that is adapted to prevent fuel from flowing through the injector outlet;
• and
• (ii) movable, responsive to magnetic force produced by energizing the electromagnetic coil assembly, to an open position that is adapted to permit fuel to flow through the injector outlet;
• a spring that:
• (i) imparts a force to the movable pintle, with a first end of the spring contacting a first spring-seating surface of the movable pintle;
• and
• (ii) biases the movable pintle to the closed position;
• and
• a calibration insert that:
• (i) is located within the insert-receiving section of the inlet passage;
• (ii) has a periphery that is wider than the narrowed diameter of the narrowed section of the inlet passage;
• (iii) defines a calibration insert fuel passage that extends through the calibration insert;
• (iv) defines a ledge that is within the calibration insert fuel passage and that is offset from a bottom end of the calibration insert that is oriented toward the injector outlet, with the ledge providing a second spring-seating surface that contacts a second end of the spring;
• and
• (v) is user movable back and forth along a range of positions within the inlet passage, while the upper housing portion and the lower housing portion are assembled together, to change a distance between the first spring-seating surface of the movable pintle and the second spring-seating surface of the ledge of the calibration insert, and to calibrate the force imparted by the spring to the movable pintle.