HYDRAULIC COMPENSATOR FOR A PIEZOELECTRICAL FUEL INJECTOR

摘要

A fuel injector comprises a body having a longitudinal axis, a piezoelectric actuator that has first and second ends, a needle coupled to the first end of the piezoelectric actuator, and a hydraulic compensator coupled the second end of the piezoelectric actuator. The piezoelectric actuator includes a plurality of piezoelectric elements along the axis between the first and second ends. The needle is movable between a first configuration permitting fuel injection and a second configuration preventing fuel injection. And the hydraulic compensator axially positions the piezoelectric actuator with respect to the body in response to temperature variation. Also, a method of compensating for thermal expansion or contraction of the fuel injector comprises providing fuel from a fuel supply to the fuel injector; and axially adjusting the piezoelectric actuator with respect to the body in response to temperature variation. The axially adjusting includes moving hydraulic oil through an orifice connecting first and second hydraulic oil reservoirs.