Modeling And Simulation Of Ship Dual-fuel Engine Work Process

With the stricter requirements of International Maritime Organization for shipping waste emissions and the higher level of the oil price,natural gas as a kind of clean energy has its own advantages such as lower price,considerable reserves and almost no pollution.Therefore,it has been using in the shipping fuel and becoming one of the substitute of the traditional diesel.The strategy of natural gas as the fuel of the dual fuel engine has developed rapidly and widely used.In the thesis,6S80ME-GI dual fuel engine from MAN B&W company is the study object.First,studying the working process of the dual fuel engine in details.Second,introducing the differences between the model engine and the regular diesel engine:including the fuel injection system,double wall structure and gas leakage monitoring system,etc.finally,it introduces three models of the operation modes:dual fuel mode,diesel mode and the maximum gas mode.In this thesis,the following work includes several parts.Building the mathematics model of the 6S80ME-GI dual fuel engine based on the working process,these models are the main components of the model engine:cylinder model,inlet and exhaust system model,turbocharger model,scavenging box model,and air cooler model.Then simulating each of the model in the Simulink platform.In the simulation of the cylinder working process,the working state of the engine in the double fuel mode,analyzing the diesel mode and the maximum gas mode.And then under the condition that the engine load is constant,changing the ratio of gas and fuel,and analyzing the influence of different gas substitution rate on the working state of the engine.Finally,confirming the difference between the dual fuel engine and the ordinary engine,and analyzing whether the feasibility of the cylinder module is obtained.Multi-cylinder combined output model,through the multi-cylinder joint output torque and pressure,setting a single cylinder to stop the supply of fuel and gas failure analysis of the parameters of the changes,getting the feasibility of multi-cylinder joint module.In the dual-fuel engine working process of the dynamic model,the feasibility of the model is verified by changing the engine loading.Finally,the simulation experiment of the engine's integral model is used to verify the accuracy of the model established in this paper,and the study of dual fuel engine has some value.