Optimization of the Combustion in Large Marine Diesel Engine by Controlling the Exhaust Gas

The diesel engine performance and emissions are strongly linked to the air-fuel mix which is a function of the oxygen content in the exhaust gases. It is possible to regulate the air-fuel mixture in a diesel engine, by controlling the turbocharger speed through a bypass valve by a regulator whose reference is the oxygen content in the exhaust gas. For the execution of this work we have taken as a model a marine diesel engine type Wartsila NSD 12 ZAV 40S with 8200 Kw nominal power, using the engine shop trials data. Engine manufacturers provide charts on relationships gas flow, power etc. The work is based on these curves for modeling the control system

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Simulation is carried out using Matlab and Simulink and simulation results are presented to illustrate the performances of this approach.