Optimization Analysis Of Fuel And Gas Parameters In Combustion Chamber Of Heavy Diesel Engine

The diesel engine has been occupying the dominant position of heavy power equipment for a long time because of its large power range,high torque output and low fuel consumption,At the same time,the internal combustion engine emissions pollution draws more and more attentions of the world,especially since the 13 th Five-Year national planning,and further strengthen the regulation of the environment,Therefore,more stringent emission regulations of the internal combustion engine industry which further enhanced the research of internal combustion engine,To improve the power and economy performance and thermal efficiency of combustion and less emission in the mean time.In this paper,a heavy diesel engine is as the research object,The engine performance simulation and simulation study of flow,spray and combustion characteristics in the combustion chamber were carried out which based on the engine bench test data.In the simulation of engine performance,the performance model of the diesel engine is established by using the software GT-power,and the engine performance model is calibrated;then the match analysis of diesel engine and turbocharger according to the test data o,and get a better matching of turbocharger.On the study of flow,spray and combustion characteristics,using the software Converge to establish a combustion chamber geometry model to adjust the spray,combustion and turbulence model.The calculation results and the test results were compared to ensure the accuracy of the model and analysis of combustion chamber the internal temperature、velocity、equivalence ratio distribution etc.Finally,based on the single factor and orthogonal design method respectively,the fuel and gas parameters were investigated by single variable analysis which are the injector nozzle hole number,injection pressure,injection timing,injection hole angle,swirl ratio of combustion.finally,By orthogonal design method 5 factors and five levels to analysis and optimization the engine power,economy and emission as optimization index of comprehensive optimization,finally obtains the fuel and gas parameters influence on the comprehensive evaluation index from big to small was the swirl ratio、nozzle angle、 injection timing、 injection pressure and nozzle hole number and the best matching scheme is that the number of nozzle holes is 6 holes,injection pressure is 200 MPa,the 7° of fuel injection timing,the inject angle is 155°,the swirl ratio is 1.2 which has the best comprehensive performance.Compared to the engine prototype,The optimized indicated power decreased by 1.31% compared with the pre optimization,and the fuel consumption increased by 1.31%.For the NOx emission,the amount of Soot was reduced by 12.7% compared with that before optimization,compared with 24.1% before the optimization.