Development of an extended mean value engine model for predicting the marine two-stroke engine operation at varying settings

This study focuses on the development of an extended MVEM capable of predicting the engine performance parameters (thermodynamic, flow and mechanical) of two-stroke marine engines at varying settings of injection timing and turbine area. The extension employed mapping of a number of the engine parameters carried out based on a zero-dimensional model. Both the zero-dimensional and the mean value engine models were developed in MATLAB/Simulink environment following the same modular approach and their accuracy was validated against experimental data from shop trials. Subsequently, the zero-dimensional model was used for engine parametric simulation by changing the start of fuel injection and the turbocharger turbine area. By analyzing the derived results, the relationships between the investigated engine parameters were established and the appropriate corrections were applied in the MVEM. The extended MVEM was benchmarked against the zero-dimensional model and MVEM at steady and transient conditions and the derived results were analysed and discussed revealing the advantages and limitations of the investigated modelling approaches. Based on the obtained results, the proposed extension methodology improves the MVEM prediction capability without considerably increasing the complexity and the execution time and therefore, it can be employed for the engine performance prediction in control system design investigations overcoming limitations of the MVEM.