Study On Working Process Modeling And Simulation Of Marine Inteligent Low Speed Diesel Engine

Intelligent diesel engine is more and more widely used in merchant ship. It is of great significance to establish mathematical models, which can accurately reflect the steady state and transient performance of intelligent diesel engine unit so that it can be used for its control, simulation and performance analysis.In this thesis, a 7RT-flex60C diesel engine is used as the modeling and simulation object. Main contributions of this thesis are listed as follows:1) The existing volume-method's mathematical model of diesel engine is revised so that the diesel engine working process division can be dynamically changed in terms of the change of operating condition. Therefore, a dynamic mathematical model of intelligent diesel engine is established. According to the working process dynamic mathematical model of intelligence diesel engine, a dynamic simulation model via Matlab/Simulink is established. It is shown that the simulation result is in good agreement with the stand test data, and the simulation indicating diagram is basically coincident with the measured one. It is also indicated that the dynamic process meets with the actual situation and calculation speed also meets with the requirements of real-time simulation.2) Based on the analysis of fuel common rail system in Wartsila 7RT-flex60C marine electronic-control diesel engine, the system's mathematical model is established. Matlab/Simulink is employed to establish its simulation model. From the model, fuel injecting process influence is analyzed at the condition of changing fuel common rail pressure, injection timing, common rail valve and servo oil rail control valve's structure parameters. The co-simulation is conducted to intelligent diesel engine working process simulation. Rail pressure curve and nozzle cavity pressure curve of fuel common rail system in a typical operating are obtained via co-simulation. These curves represent the fluctuations of common rail pressure, fuel injection timing and injection duration at different working conditions. The influence of fuel common rail pressure's fluctuations from fuel common rail pressure, injection quantity and the volume of the common rail is also attained. Simulation results show that the established fuel common rail system mathematical model is accurate and the simulation dynamic process meets with the actual situation.3) Web3D techniques including VRML, JAVA technology, animation & scripting language, media technology are applied in marine intelligent diesel engine's visual simulation, then three-dimensional visual model of overall structure and the cylinder internal structure of this kind of diesel engine is set up. Interface and communication programmes are developed using C++, then dynamic interactive process is completed among diesel engine visual simulation model, the work process simulation model and the common rail system simulation model. This study serves as a solid foundation for development of the online real-time interactive intelligent diesel engine virtual training system.Diesel engine modeling and simulation is an important aspect for ship power plant. In this thesis, the 7RT-flex60C diesel engine working process mathematical model and fuel common rail system mathematical model are established using improved volumetric method. By meaning of Matlab/Simulink, the simulation models which are mentioned above are constructed and visual simulation model based on Web3D technique is also set up, then dynamic interaction is achieved among visual simulation model, the working process and the fuel oil common rail system simulation model. All of the work in this thesis serves as a good foundation for development of a novel intelligent diesel engine simulator.