Injector for reductant delivery unit having fluid volume reduction assembly

A fluid injector, comprising:

• a fluid inlet disposed at a first end and configured to receive a fluid, and a fluid outlet disposed at a second end of the fluid injector for discharging the fluid, the fluid injector defining a fluid path for the fluid from the fluid inlet to the fluid outlet;
• a tube member having an end disposed at the fluid inlet of the fluid injector, the tube member configured to pass fluid along the fluid path;
• a filter disposed in the tube member proximal to the fluid inlet of the fluid injector;
• a calibration filter tube disposed in the tube member, the calibration filter tube having a first end portion and a second end, and further including a bore defined in an axial direction through the calibration filter tube, the bore defining at least a portion of the fluid path through the fluid injector, the calibration filter tube including a plurality of holes which extend from the bore to an outer surface of the calibration filter tube;
• wherein the outer surface of the calibration filter tube is an outer radial surface of the calibration filter tube which extends between axial end surfaces of the calibration filter tube,
• wherein the plurality of holes extend in a radial direction between the bore of the calibration filter tube and the outer surface thereof,
• a volume reduction member having a bore though which the calibration filter tube extends, the volume reduction member occupying a space between the outer surface of
• the calibration filter tube and an inner surface of the tube member, the volume reduction member being constructed from resilient, compressible material;
• an actuator unit disposed within the fluid injector downstream of the calibration filter tube, the actuator unit engaging the second end of the calibration filter tube;
• and a valve assembly operatively coupled to the actuator unit, wherein a position of the calibration filter tube within the tube member sets an opposing opening force of the valve assembly.