Extracting physical parameters from system identification of a natural gas engine

Simulation results are shown for linear system identification carried out to identify key physical parameters of a lean-burn natural gas engine with transmission. The natural gas engine can be described by a nonlinear plant with three states. The dynamic state equations of the model involve parameters that might vary depending on ambient conditions, type of transmission connected to the engine, and parametric variation from engine to engine. Linear system identification is used around an operating point to identify key physical parameters of the nonlinear model (e.g., engine/transmission inertia) that can be used to tune linear or nonlinear controllers.