Modeling and control of a high pressure diesel common rail injection system for maritime applications

Feeding pressure control is paramount for injection system performance stability, in order to provide the engine the same fuel quantity when equal electric command is provided to the injector driver. The present work is aimed at modeling a high pressure common rail diesel injection system and designing a rail pressure controller to be easily implemented on the electric board of a current controller for the injection system high pressure pump. In this project a simple but effective way of restoring rail pressure after an injection event is presented and compared with a more sophisticated approach involving a coupled controller with a compensator. In particular, system identification activity has been performed on the injection system model, so as to characterize its transfer function in Laplace domain. Then the system control strategy has been defined and modified due to actuator saturation limits. Finally, relying once again on system identification, a disturbance compensator has been designed and added to the controller system, in order to improve the rail pressure control performance.