Fractional-Order Modeling of High-Pressure Fluid-Dynamic Flows: An Automotive Application

Performance of internal combustion engines is strictly affected by the metering of the air/fuel mixture. Achieving accuracy in metering is difficult due to the complex fluid-dynamics of the fuel injection process. However, injection control can benefit from appropriate models describing the process dynamics. To this aim, this work develops a mathematical model of the common rail diesel electro-injector. Fractional-order modeling of pressure wave propagation in the pipes is investigated with respect to the integer order modeling approach. A comparison between simulation and experimental results validates the fractional-order model, that also shows better prediction capabilities than an integer-order model. Then the proposed model is suitable for mechanical optimization of the injector and for deriving fuel rate shaping strategies.