In this study, a model is developed to simulate the dynamics of an internal combustion engine, and it is calibrated and validated against reliable experimental data, making it a tool that can effectively be adopted to conduct emission predictions. In this work, the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine, a four-stroke engine used in the maritime field. Results from the bench tests are used for the calibration of the model. Finally, the calibration of the model and its validation with full-scale data measured at sea are presented. The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions, which are compared with similar results obtained with emission factors. The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7% on power, torque, and consumption. The model provides encouraging results, suggesting further applications, such as in the study on transient conditions, coupling of the engine model with the ship model for a complete simulation of the operating conditions, and optimization studies on consumption and emissions. The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work.

The performance of a marine dual-fuel engine, equipped with an innovative hybrid turbocharger producing electric power to satisfy part of the ship’s electric load, is presented by a simulation comparison with the traditional turbocharging technology. The two distinct fuel types, combined with the hybrid turbocharger, involve a substantial change in the engine control modes, resulting in more flexible and efficient power management. Therefore, the investigation requires a numerical analysis depending on the engine load variation, in both fuelling modes, to highlight different behaviours. In detail, a dual-fuel engine simulation model is validated for a particular application in order to perform a complete comparison, reported in tabular and graphical form, between the two examined turbocharging solutions. The simulation analysis is presented in terms of the engine working data and overall energy conversion efficiency.

The paper describes an original Waste Heat Recovery (WHR) variable layout plant to produce steam from the exhaustgases of marine dual-fuel engines. A large part of the steam feeds an electric turbogenerator to improve the ship's energy efficiency.The layout of the proposed steam plant is conceived in a double configuration to satisfy both the stack temperature constraints of theengine exhaust gas, due to the use of diesel oil (no less than 160°C as outlet gas temperature) or natural gas (there are no particularstack temperature limits). The comparison with a traditional WHR single pressure steam plant shows the potential benefits of thevariable configuration. Indeed, the proposed solution allows a better exploitation of the potential thermal energy of the natural gas,without precluding a proper performance even in diesel mode, with a moderate weight increase compared to a single pressure WHR system.