ARMATURE MOTION CONTROL METHOD AND APPARATUS FOR A FUEL INJECTOR

摘要

An injector needle (14)/armature (12) assembly stroke is controlled so as to minimize opening and closing impact forces. The controlled motion eliminates or significantly reduces the problems associated with valve bounce, providing less acoustic emission, reduced wear, improved spray characteristics and better flow regulation. The current applied (TS) to the electromagnetic coil (22) of the injector in accordance with a modified injector timing pulse waveform (TS, T1, T2, T3, T4, TF) serves to reduce impact velocities at each end of the armature stroke. The waveform can be optimized for a class of injectors with a pulse width modulated waveform, repeatedly re-energizing and de-energizing the electromagnetic coil in accordance with an optimized on/off pulse train.