Adaptive Boost Pressure Control for Four-Stroke Diesel Engine Marine Application in the Presence of Dynamic Uncertainties

Robustness of the control system in marine engines with respect to its time-varying dynamics has recently become an important research topic. The variation of dynamics, caused primarily by the mechanical wear of components or their faults originating from tough operating condition, can lead to the overall control system instability (or marginal stability, depending on how severe the variation is). The biggest issue is that the marine engines cannot always be fixed fast enough (especially on large cargo vessels, spending hundreds of hours cruising). In this paper, a control adaptation (indirect model-reference adaptive control) is proposed to deal with the engine parameter variation in a way that the original system response is preserved. The stability and robustness of the proposed control system are studied by means of numerical simulations. Finally, the performance of the control concept is validated on the medium-speed diesel engine test bed at constant speed under load transients. Superior performance compared with fixed-parameter proportional-integral control is demonstrated.