Modeling And Simulation Of Marine Two-stroke Electronically Fuel Injection Diesel Engine

Since the 21 st century,the development of Marine diesel engine has entered a new development stage of electronic control,and the control and management of diesel engine have been realized electronically,informationized and intelligentized.As a typical electronically fuel injection(EFI)diesel engine,W(?)rtsil(?) RT-flex intelligent diesel engine has been widely promoted and applied.At the same time,the Marine Engine Room Simulator(MERS)has become a necessary equipment for marine education and training due to its high efficiency and safety.Therefore,the in-depth study of the complete mathematical model of the EFI diesel engine and the simulation verification can provide the basis for the further development of the EFI diesel engine and MERS by the design and development of the new version of the simulator,which has a wide range of practical significance.In view of the lack of an integrated model in the current domestic research on modeling and simulation of EFI diesel engines,this thesis has improved the integrated modeling method of marine two-stroke EFI diesel engines.Generally,when modeling marine diesel engines,only the working process is modeled,and the fuel injection and exhaust processes controlled by the common rail system(CR)are only simple MAP settings,or simple matching with the main engine speed.In fact,the CR for fuel injection and exhaust control has a greater impact on the dynamic response performance of the diesel engine.This thesis takes W(?)rtsil(?)’s 6RT-flex58 TD intelligent diesel engine as the research object,analyzes the composition and working principle of the EFI diesel engine,and divides the components based on the volumetric modular modeling idea,the working process model of the diesel engine is established,including cylinder model,intake and exhaust manifold model,turbocharger model,air cooler model,dynamic model matching the engine speed and ship speed and thrust.Each sub-model is related to mass and energy.And on this basis,the CR model of fuel injection and exhaust control is refined,including fuel oil CR and servo oil CR.According to the fluid state continuity equation and motion equation,the complex heat transfer process of the working fluid is simplified,and continuous mathematical modeling of high-pressure oil pumps,intermediate oil reservoirs,accumulator,common rail pipes,ICU,VCU,fuel injectors,exhaust valves,etc.The statecontinuous mathematical modeling obtains the fuel injection volume of the CR and the opening and closing status of the exhaust valve,which completes the integrated dynamic model of the EFI diesel engine based on the volumetric method.Matlab/Simulink is used to simulate the mathematical models of each sub-module separately,and connect them according to the input and output relationship between the modules.Combining the various parameters of the actual ship’s main engine and the bench test data,the integrated model is debugged and verified based on the typical working conditions,and the integrated model simulation program design is completed.The simulation model can obtain the parameters dynamic change process curve which verified the accuracy of the model such as the pressure and temperature of cylinder and manifold,engine speed,power,quantity of fuel oil and exhaust state of CR and so on,which verified the accuracy of the dynamic model.By adjusting the stable speed of each working condition under the full-load working condition and the stable running state,it is verified that the real-time response performance of the integrated dynamic model;at the same time,by comparing with the diesel engine working process model and the simplified CR model,the error of the integrated model of the refined CR fuel injection and exhaust control is controlled below 2%,the error is further reduced,the model runs more stable,and more suitable for the actual ship operation mechanism.In order to solve the problems of low model reuse rate,data occlusion,and high coupling caused by the data pool hidden in the applications of the old version MERS,takes the integrated simulation model as the core,and the WPF framework and technology are used in the Visual Studio environment.The design of the main engine part of the 2D visual simulation simulator is carried out.