Generic Marine Diesel Engine Modelling and Simulation Based on 20-sim

Abstract

This Master thesis is about creating a generic marine diesel engine model and simulating in 20-sim. The methodology is applying marine diesel engine working principle into bond graph. The first step is to build a single cylinder engine model consists of governor, cylinder, reciprocating components, crank shaft and load model. The basic bond graph elements are applied. When the single cylinder model is completed, due to the same working theory, connect 6 cylinders in series to build a 6-cylinder engine model. There are small adjustments such as crank angle differences are set up by submodels. The models are built separately both for two-stoke diesel engine and four-stroke diesel engine. The differences between these two types of engines are also explained. To achieve creating a generic model, the model should fit other types of engines. By inputting some main data of engine such as bore diameters, stroke length and maximum cylinder pressure, the model can work as selected new engine. Scaling factors and scaled parameters are discussed in details. There is a propeller model which was built by previous student is connected to the diesel engine model. The propeller selection is discussed as well, so that the engine model and the propeller model can match each other and work well. When the bond graph model is ready, input it and parameters into 20-sim and simulate it. After receiving the simulation results, explanations are offered to each plot. The plots are reasonable and close to the assumptions. The simulation results prove that the engine model can be used in the future projects as a generic model. Due to the limitation of time and ability, future work is listed so the future students or researchers can develop the model more perfect or integrate this model to other ship systems.