Modelling and identification of a piezoelectrically driven fuel injection control valve

Abstract

In this article, the modelling and identification of a piezoelectrically driven control valve of a common-rail diesel fuel injector in an experimental setup is presented. The piezoelectric actuator of the control valve exhibits a strong temperature dependence. Furthermore, an unknown mechanical parameter in the control valve mechanics, the idle stroke value, has to be determined. An optimization-based method is used for temperature adaptation as well as for the identification of the unknown idle stroke value. Both the suppression of the temperature dependence and the exact knowledge of the idle stroke value are essential for the opening width and opening point of time of the control valve and thus for the accuracy of the fuel injection. The identification task becomes even more challenging because only the electrical signals of the actuator, namely voltage and current, are measurable. The method is successfully validated in an experimental setup.