Exhaust Gas Recirculation Control for Large Diesel Engines – Achievable Performance with SISO Design

This paper investigates control possibilities for Exhaust Gas Recirculation (EGR) on large diesel engines. The goal is to reduce the amount of NOx in the exhaust gas by reducing the oxygen concentration available for combustion. Control limitations imposed by the system are assessed using linear analysis of the highly non-linear dynamics. Control architectures are investigated and performance in terms of disturbance rejection and reference tracking are investigated under model uncertainty. Classical feed-forward and feedback controller designs are investigated using classical and Quantitative Feedback Theory (QFT) designs. Validation of the controller is made on the model with focus on disturbance reduction ability.