Modeling, identification and state estimation of diesel engine torque and NOx dynamics in response to fuel quantity and timing excitations

A systems approach to modeling the response of brake torque and NOx emissions of a high-speed common-rail diesel engine to combined excitations in fuel quantity and timing is investigated. A multivariate mean-value model is proposed, identified and validated. The model structure is derived from and extends an existing physical model (Jankovic, E., et al., 1998), (Upadhyay, D, et al, 2002). This model structure is linearized and its parameters are then identified at selected engine operating points. Observers are presented for the physically based model and it is shown that torque and NOx can be predicted using existing measurements of manifold pressure and mass air flow.