近后喷射对柴油机颗粒粒径分布的影响  

Effect of Close Post-Injection on Particle Size Distribution in Diesel Engine

作　　者：罗悦齐[1] 李新令[1] 李昂[1] 黄震[1] 

机构地区：[1]上海交通大学动力机械与工程教育部重点实验室,上海200240

出　　处：《工程热物理学报》2016年第7期1577-1582,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金重大国际合作项目(No.51210010);科技部港澳台科技合作专项(No.2014DFH90020)

摘　　要：试验研究了近后喷射对柴油机排放颗粒物粒径分布及数量浓度的影响,结合不同工况下的燃烧分析对近后喷射影响颗粒物排放特性的机理进行了阐释。重点分析了在发动机低负荷和中等负荷条件下,后喷间隔和后喷油量两个参数对颗粒物总数量排放的抑制或促进作用。研究发现,低后喷油量和大后喷间隔的后喷策略是减少颗粒物排放的最优化策略;近后喷射的应用仅在较高发动机负荷工况下有利于减少颗粒物总排放量,而在低负荷下,近后喷射只对核态颗粒有显著的抑制效果;近后喷射的引入降低了燃烧前期的缸内温度,提高了燃烧后期的温度,有利于促进颗粒物氧化,从而达到减少颗粒物排放的效果;这一燃烧特性也有利于减少NO_x的生成。In this study,the effects of close post-injection strategies on particle size distributions and number concentrations in diesel engine are analyzed experimentally.The particle formation/oxidation conditions with different injection strategies were elucidated based on combustion analysis.One focus is the effects of post-injection fuel mass and interval on the total particle emissions.Two representative low and medium engine loads are chosen to perform the experiments.It was found that the optimal strategy for reducing particle emission is lower post-injection fuel mass with larger interval.Post-injection can only reduce particle emission effectively in higher load condition,while in lower load,post-injection only reduces nucleation particles notably.Combustion analysis showed that the post-injection lowered the incylinder temperature in the early stage and raised temperature in the later stage,therefore it reduced particle emission by promoting particle oxidation.NO_x is also reduced as post-injection is adopted due to the lowered peak temperature.

关 键 词：共轨柴油机 颗粒物粒径分布 近后喷射 燃烧分析 

分 类 号：TK431[动力工程及工程热物理—动力机械及工程]