Robust Model-Based Detection of Faults in the Air Path of Diesel Engines

This paper discusses the robust model-based fault detection filter design problem for faults in the air path of diesel engines. Two failure modes in the air path, namely, the Exhaust Gas Recirculation (EGR-Actuator) and Variable Geometry Turbocharger (VGT-Actuator) bias faults were considered. The objective of the design is the detection of failures, which is robust against model uncertainties and external disturbances. By using aH-infinity optimization approach the filter robustness is ensured by the application of a design trade-off that is made between the worst-case disturbance and the L2 norm of the filter error. Beyond the classical state estimation, the method requires the solution of a linear-quadratic optimization problem that leads to the solution of the Modified Filter Algebraic Riccati Equation.