Numerical Simulation For Effects Of Fuel Injector Parameters On Combustion Of Di Diesel Engine

The process of diesel engine's combustion is an automatic chemical reaction under the conditions of mixture, certain level of temperature and pressure. The formulation of mixture affects engine's combustion process and emission performance. A key aspect affecting the mixture and combustion is the spraying performance of fuel. Further the parameters of injector directly affect the performance of spray, so the research of injector's parameters means a lot for optimizing the combustion process and emission feature. Therefore, the study of effects of fuel injector parameters on combustion and emission of DI diesel engine is a meaningful work.This paper discussed the 3D numerical simulating model and numerical calculating method of in-cylinder combustion process, theoretically analyzed the in-cylinder air phase turbulence flowing model, diesel-fuel's spraying model and in-cylinder combustion model. Upon a prototype diesel engine of YT3105, we implemented the numerical simulation of it's in-cylinder flowing process, spraying process and combustion process utilizing the 3D CFD software AVL Fire, which analyzed the injector's main parameters'(such as hole number, spraying angle, injection timing etc.) affection rule against the direct injection diesel engine's combustion process and emission feature. Here we put our stress on analyzing the evolving regulation of the in-cylinder flow field, the spatial profile of fuel spray, the in-cylinder fuel to air equivalent ratio, temperature distribution feature and the emission formulation conditions. Furthermore, we compared the simulation result and experiment result, which verified the rationality of simulation model. We analyzed the model whose combustion chamber and injector are eccentric to the cylinder centerline when we already have analyzed the situation that they are concentric to the cylinder.The results show that, number of nozzle holes affects the quality of fuel's pulverization; spraying angle affects the fuel's spatial distribution. The mixture quality could be lifted when properly select those parameters above, as well as optimizing the DI diesel engine's combustion process and reduce emission.