Development of an adaptive driving module for piezo actuated diesel fuel injector

Piezo actuated diesel fuel injector is gradually replacing the conventional solenoid injector since it can provide a more flexible control ability of the fuel injection. Engine performance can be benefitted from such flexible injection. For fully utilizing the advantages of the piezo actuated injector, precision control of the piezo actuator is therefore needed. In this work, a programmable injector driving module is presented. Comparison between different control strategies of piezo and solenoid injectors is summarized. Based on this driving module, an adaptive controller with online self-tuning capability is designed and implemented. Internal control parameters are estimated by simulation and subsequently tuned online in real application by a self-tuning algorithm to reduce the deviations between the driving current profile and the reference profile. This module is verified under different fuel pressures and injection durations with various configurations of executing power voltages and current profiles. Results show that this driving module and self-tuning algorithm are capable to operate accurately and assure the injection quality of the piezo injectors.