Nonlinear unknown input observer for intake leakage estimation in diesel engines

Intake leakage estimation problem in diesel engines is addressed in this paper. The need to guarantee high-performance engine behavior and in particular to respect the environmentally-based legislative regulations motivates this work. Today, diesel engines monitoring has become an obligation and a necessity. In this paper, based on a Takagi-Sugeno (TS) fuzzy model of the engine, a nonlinear unknown input observer (NUIO) is used to estimate the intake leakage mass flow rate. The advantage of the proposed method is that no a priori assumption on the intake leakage size is required. The diagnosis system is successfully evaluated using an advanced diesel engine professional simulator AMEsim(LMS).