Simulation Of Optimization Of Combustion Chamber For Diesel/Natural Gas Dual-Fuel Engine

As people pay more attention to energy and environmental problems,the regulations of marine diesel engine emission NOx are becoming more and more strict.Reducing the emission of NOx is one of the environmental pollution problems that need to be solved urgently.Therefore,reducing the emission of NOx has become the focus of research by scholars.This paper applies the Miller loop coupled external EGR technology to a certain launch.The machine mainly analyzes and studies its effect on reducing the amount of NOx generated.The engine parameters and the experimental data are input into the GT-Power simulation software.The main components are set up,the simulation model and the parameters are well debugged.The simulation results of the working process of the whole machine are compared with the experimental data of the simulation platform.The results are well verified and calibrated within the allowable range of error.The model is simulated by Miller cycle,EGR and Miller cycle combined with EGR.First,on the basis of the verified and calibrated simulation model,the Miller cycle is simulated first.The intake pressure plays a very important role in the Miller cycle simulation calculation,so the simulation calculation of the Miller cycle is to increase the pressure of the intake by the parameter setting interface of the turbocharger and increase the intake air intake.The size of the pressure pressure should be determined according to the actual pressure,and the influence of the intake pressure on the diesel engine parameters and the reduction of NOx production is analyzed.This paper simulates and calculates the Miller cycle of variable cam type inlet valve in advance.Under the load conditions of 25%,50%,75%and 100%respectively,the selection of Miller degree is 20,40,50 and 60 respectively.The influence of diferent Miller degrees on the pressure,power,fuel consumption,temperature and NOx production in the cylinder is simulated.The simulation results show that,under the condition of 100%load,under the condition of Miller degree 50,the reduction of NOx generation quantity reaches the best,the reduced 100 component reaches about 20%,and the diesel engine’s power and economy are basically unchanged.Secondly,on the basis of the verified and calibrated simulation model,the simulation calculation of an engine exhaust gas recirculation is carried out on a diesel engine.Under the conditions of 25%,50%,75%and 100%,the selection of EGR rate is 2%,4%,6%and 8%respectively,and the oil consumption,power and power of diesel engine are not equal to the EGR rate.The effect of temperature and the amount of NOx generated.The simulation results show that the amount of NOx generation decreases with the increase of EGR rate.Finally,on the basis of the verified and calibrated simulation model,the Miller cycle combined with EGR technology is applied to the simulation and analysis of the TBD234V6 diesel engine.Under the conditions of 25%,50%,75%and 100%,when Miller’s degree is 20,40,50,60,and the EGR rate is 2%,4%,6%,8%,the influence of the Miller cycle combined with EGR on the power,fuel consumption,temperature and NOx production of the diesel engine is analyzed.The analysis results show that under the condition of 100%load,6%EGR rate and M50,the Miller cycle combined with EGR technology can reduce the NOx optimum and reduce the 100%to 36.58%.The simulation of this paper provides a theoretical basis for the application of the Miller cycle combined with EGR technology to practical practice in the future,and lays a solid foundation for the practical application of the project.