Method and fuel injector for setting gaseous injector static flow rate with injector stroke

A fuel injector comprising:

• a housing having a hollow passage;
• a longitudinal axis extending through the hollow passage;
• a seat disposed at one end of the hollow passage;
• a needle slidably mounted in the hollow passage and operable between a first position when the needle engages the seat and a second position when the needle is disposed away from the seat, a first flow area being formed by a minimum frusto-conical area between the seat and the needle when the needle is disposed away from the seat;
• and having an opening at the one end of the hollow passage proximate to the seat, the opening having a second flow area larger than the first flow area, the second flow area is approximately two times larger than the first flow area.

A method for assembling a fuel injector having a housing and a valve disposed within the housing, the valve including a seat having an opening and a needle, the method comprising:

• determining a desired fuel flow rate for the injector;
• providing an opening of a first flow area in the seat to permit a fuel flow rate greater than the desired fuel flow rate;
• and
• setting an injector stroke of the needle that forms a second flow area of approximately one-half the first flow area so as to provide the desired flow rate.

A method for generating different flow rates from each of a plurality of fuel injectors, the method comprising:

• providing substantially uniformly dimensioned components for each of the plurality of fuel injectors so that a seat provides a first flow area;
• determining a desired respective gaseous flow rate for each of the plurality of fuel injectors;
• setting an injector stroke with respect to each of the plurality of fuel injectors such that the injector stroke forms a second flow area between a needle and the seat of approximately one half the first flow area to provide a plurality of flow rates greater than a first flow rate;
• and
• securing the components of the first of the plurality of fuel injectors in a first position to obtain a first injector stroke and securing the components of the second of the plurality of fuel injectors in a second position to obtain a second injector stroke.