A Mixed Causality Approach to Residual Generation Utilizing Equation System Solvers and Differential-Algebraic Equation Theory

The FDI approach to model-based diagnosis is considered. We present a method for residual generation that combines integral and derivative causality, and also utilizes equation system solvers and theory of differential-algebraic equation systems. To achieve this, a framework for computation of variables from sets of dependent differential and/or algebraic equations is introduced. The proposed method is applied to a model of the gas flow in an automotive diesel engine. The application clearly shows the benefit of using a mixed causality approach for residual generation compared with solely integral or derivative causality