Internal combustion engine fuel injector actuating unit has cavity between piezoelectric actuator and casing filled with vibration damping material

摘要

The actuating unit, comprising a piezoelectric actuator (2) inside a casing (25), has the cavity (27) between the actuator and the casing filled at least partially with a vibration damping material (28). The damping material can be a solid with flexional elasticity which fills the cavity and transverse grooves (252) in the casing's inner surface (251), and the actuator is inserted in a hollow sleeve (22) with recessed connecting it to the damping material. In a variant the damping material can be a liquid which fills the cavity to a level related to the mechanical vibration frequency transmitted by the actuator to the casing.