Piezoelectric fuel injector system, method for estimating timing characteristics of a fuel injection event

摘要

This disclosure provides a fuel injector system and method in which the timing of events in during period of fuel injection of a piezoelectric-actuated fuel injector are estimated based on sensed forces within the injector. The force sensor is positioned between a piezoelectric actuator and a hydraulic link assembly mechanically coupled with the piezoelectric actuator, and the force sensor operable to output a signal corresponding to forces between the piezoelectric actuator and the hydraulic link assembly. From information contained in the sensor output signal, timing in the injection period of at least one fueling characteristic based can be estimated to allow for adjusting fuel injector characteristics to compensate for variations affecting fuel injection, such as manufacturing tolerances, environmental conditions, and deterioration/wear.

主权项

1. A piezoelectric-actuated fuel injector system for injecting fuel into a combustion chamber of an internal combustion engine, comprising:
an injector body including a plunger, a nozzle housing having a nozzle cavity, injector body and said nozzle housing, and an injector orifice communicating with one end of said nozzle cavity to inject fuel into the combustion chamber; a nozzle valve element positioned in said nozzle cavity adjacent said injector orifice, said nozzle valve movable between an open position in which fuel flows through said injector orifice into the combustion chamber and a closed position in which fuel flow through said injector orifice is blocked; a piezoelectric actuator movable to expand in a first direction and to contract in a second direction; a hydraulic link assembly positioned within said nozzle cavity, said hydraulic link assembly operably connected with the piezoelectric actuator such that movement of the piezoelectric actuator in the first direction causes the nozzle valve element to move to said open position and movement of said piezoelectric actuator in said second direction causes the valve element to move to said closed position; and a force sensor positioned between said piezoelectric actuator and said hydraulic link assembly, said force sensor adapted to provide a signal indicative of forces between the piezoelectric actuator and the hydraulic link assembly during a fuel injection period; a controller adapted to receive the signal provided by the force sensor, identify at least one of a maximum value and a valley minima value of the monitored output signal, and estimate timing in the injection period of at least one fueling characteristic based on the at least one identified value.