Actuator fault detection and isolation for diesel engines

This work addresses the issues of actuator fault detection and isolation for diesel engines. We are particularly interested to diagnosis faults affecting the Exhaust Gas Recirculation (EGR) and the variable Nozzle Turbine (VNT) actuator valves. To accomplish this goal, a residual generator based on a nonlinear mean value model of the diesel engine is proposed using a bank of observer. Each residual on the proposed scheme is based on a nonlinear unknown input observer and designed to be insensitive to only one fault. By using this kind of scheme, the actuator faults can be easily isolated since only one residual goes to zero while the others do not. A decision algorithm based on multi-CUSUM is used. The performances of the proposed approach are shown through the application to a diesel engine model.