| 摘要 |
A fuel injector train having a variable injection rate includes a fuel injector having a plunger and a plunger biasing device having a predetermined spring rate for controlling the injection rate of the injector. A cam assembly is mounted to impart force through a push rod to a rocker arm which communicates the force of the cam assembly to the fuel injector plunger. In some embodiments, the push rod collapses axially a short distance in response to axial force applied thereto. The push rod has an inherent bias against collapsing that is less than the total bias of the injector biasing device so that during a portion of the injection cycle, part of the force imparted to the push rod collapses the push rod to operate the injector at a reduced rate. In another embodiment, the rocker arm is formed with a closable gap between its first and second ends, and the gap has an inherent bias against closing that is less than the total bias of the fuel injector biasing device. During a portion of the injection cycle, part of the force imparted to the rocker arm closes the gap to operate the injector at a reduced rate.
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