Investigation On Effect Of EUP System Parameters On The Performance Of Diesel Engine

Compared with the gasoline engine,diesel engine is more and more widely used for its advantages of high thermal efficiency,strong power output and better fuel economy.For non-road mobile machinery especially,their main power supply sources are normally from diesel engine.Nevertheless,with environmental pollutants on the rise,more attention is paid globally towards environmental protection currently.This attention has resulted in the enactment of stringent emission regulations in many countries.The main emissions of diesel engines are NOx and PM(particulate matter).NOx is harmful to human health and PM is one of the main causes of air pollution,hence the need to effectively reduce these harmful pollutants has become issues of global concern,which will contribute significantly to improving the environment.In this paper a non-road turbocharged intercooled diesel engine for mobile machinery is used as the research object.Through the combination of simulation and experiment,the parameters of the combustion system are optimized while the emission and economic performances are also improved to meet the national emission regulations standards.Firstly,the geometrical and grid models of the diesel engine combustion chamber are built by using Pro-E and Hypermesh softwares.The initial conditions and boundary conditions are determined from diesel engine experimental test bench and empirical values.After the various submodels of the simulation model are discussed and selected,AVL FIRE software is used to establish the three-dimensional calculation of the diesel engine.The simulation results are compared with the diesel engine's experimental data to verify the accuracy of the simulation model.Secondly,the effect of nozzle diameter,injection timing and EGR rate on the combustion process of the engine is studied based on single variable method.Turbulence kinetic energy,fuel/air equivalence ratio distribution,average pressure,average temperature and temperature distribution are mainly analyzed.Lastly,the test bench is set up to carry out the emission experiment according to the simulation optimized program.The effects of nozzle protrusion,nozzle diameter,fuel injection timing and EGR rate on emission and fuel consumption are investigated.From experimental results,the nozzle protrusion of 3.2 mm and nozzle diameter of 0.24 mm are determined as the optimum parametric choice.The fuel injection timing and EGR rate for the diesel engine optimum performance under each working condition are also determined.The eight condition ESC test is operated on the optimized diesel engine in a national certification emission laboratory,and the result of NOx?CO?HC?PM are 4.179 g/(kW·h)?0.494 g/(kW·h)?0.238 g/(kW·h)and 0.159 g/(kW·h)respectively.The diesel engine can meet the non-road national stage ? emission regulation.