Research On Emission Prediction And Modeling Of 6RT-flex58T-D Marine Diesel Engine

The development of intelligence ship and the implementation of the ship “energy conservation” policy have requirements for high-efficiency,intelligent and low-emission marine diesel engines.In order to meet the requirements for rapid estimation of diesel engine performance parameters and emission parameters in design phase,it is necessary to build a high-precision diesel engine with emission prediction capabilities.In this thesis,using 6RT-flex58T-D diesel engine of 30000 DWT bulk carrier "Yupeng" as an objective,a volumetric engine model of the main engine and the exhaust emission model is established in Simulink.First,by carrying out steady-state simulation experiments,the performance parameters and in-cylinder indicator diagrams of diesel engines under different loads are given,compared with experimental data,the relative error of effective power and fuel consumption rate is less than 1.8%,the relative error of burst pressure and compression pressure is within 2.18%,and the relative error of other performance parameters is mostly less than 4%,which proves that the model has a high accuracy.Then,the dynamic simulation experiment of the model was carried out for the two common dynamic changes of the set speed sudden increase and decrease and load disturbance,and the correctness of the dynamic change process of the model was verified.Finally,the CO2 and SO2 emission calculation model was established,and based on the modeling method of the dual-zone combustion model,the NO generation rate model was established according to the extended Zeldovich mechanism.The simulation results showed that the relative error of CO2 was between 5%,and the NO concentration The maximum relative error is 9.58% under 25% load,and the maximum relative error of NOx specific emissions is 6.34% under 75% load.The results show that the diesel engine model and emission model established in this thesis can meet the requirements of diesel engine performance parameters and emission parameter prediction in the initial design stage of development.It has certain guiding significance for the intelligent control of marine diesel engine,ship performance prediction and marine engine simulator research.