Modeling and control of a novel pressure regulation mechanism for common rail fuel injection systems

This paper presents the modeling and control of a novel pressure regulation mechanism for the common rail (CR) fuel injection system of internal combustion engines (ICE). The pressure pulsations inside the common rail caused by the incoming and outgoing flows negatively affect the accuracy of both injected fuel quantities and flow rates. The objective of this work is to design a new regulating mechanism to suppress the pressure pulsation in the rail. We first present the one-dimensional distributed model for the common rail developed by using fluid flow equations, which can capture the distributed dynamics of the pressure pulsations in the rail and validating it with a physics based model developed in AMESim®. We then propose the concept of an active fluid storage device like a piezoelectric actuator (PZT) to minimize the pressure fluctuations. The location of the actuator on the common rail has also been evaluated to maximize its effect. The periodic nature of the injection event due to the stroke by stroke engine operation generates pressure pulsations in the rail which are periodic when represented in the rotational angle domain. To leverage this unique dynamic phenomenon we design a time-varying internal model-based controller to compensate the pressure pulsations.