Distributed stiffness biasing spring for actuator system and fuel injector using same

摘要

A fuel injector includes a fuel injector body defining a fuel inlet and at least one fuel outlet, a valve having a first valve state and a second valve state and an actuator for the valve. The fuel injector includes a biasing spring including a cylindrical rolled sheet having a first spring end, a second spring end and defining a longitudinal center axis. The cylindrical rolled sheet is configured to change in length to bias the actuator toward the first actuator position and includes a helical seam located between the first spring end and a second spring end which has a shape adapted to reduce non-uniformity in a spring constant via distributing stiffness about the longitudinal center axis.