Modeling and design optimization of a hybrid power generator for full-electric naval propulsion

The purpose of this work is to build a model of diesel engine useful for studying new hybrid solutions for power generation. This kind of study is of significant interest particularly for the marine sector, due to recent limitations on fuel consumption and constraints imposed on the minimum powertrain efficiency. In this paper a variable-speed diesel generator model is presented. The model simulates both the dynamic behavior of the engine and the fuel consumption during the operating cycle. This model was developed using experimental results of bench tests conducted on the VL1716C2-MLL engine by Isotta Fraschini Motori (IFM) SpA. Diesel engine dynamics is based on the formulation found in the technical literature on mean value models and then adjusted through experimental data. Special attention was paid to developing the procedure to find the minimum specific fuel consumption for a given load. Initially, the presented resutls concern the correct response of the model under different load conditions. Then, the improvement in specific fuel consumption (obtained by adjusting the engine speed according to the load), in comparison with fixed speed operation, is shown.