EGR影响高速直喷柴油机NO_x和烟度排放机理的研究  

Experimental Study on Effect of EGR on NO_x and Smoke Emission of a High Speed Direct Injection Diesel Engine

作　　者：田维[1] 林学东[1] 李德刚[1] 黄丫[1] 

机构地区：[1]吉林大学汽车动态模拟国家重点实验室

出　　处：《汽车技术》2009年第9期26-29,共4页Automobile Technology

摘　　要：设计了基于步进电机的高精度EGR率可变电子控制系统,并利用该系统研究了不同工况下EGR率对柴油机NOx和烟度排放的影响。结果表明,随着负荷的增加,EGR对NOx的抑制效果明显,NOx排放对氧浓度变化的敏感性增强,而燃烧温度的增加是次要因素;随着转速的增加,NOx排放对氧浓度变化的敏感性降低,此时反应时间起主要作用,所以EGR对NOx的抑制效果减弱;烟度排放主要取决于氧的含量,故在各转速下随负荷的增加烟度随EGR率的变化越明显。In this study,an electronic control system with variable EGR rate and high precision was designed by using step motor and then the system was used to analyze the effect of EGR rate on NOx emission and smoke emission in different working conditions.The study resuhs show that as the load increased,the inhibitory effect of EGR on NOx emission becomes more obvious,the NOx emissions become more sensitive to oxygen concentration, and increase of the combustion temperature is just the secondary factor that affects the NOx emission.As the engine speed increased,the sensitivity of NOx emissions to oxygen concentration becomes weaker;the reaction duration becomes the key factor, so that the inhibitory effect of EGR on NOx emission weakened.The smoke emission depends on oxygen content to a great extent,therefore the variation of smoke emission with EGR rate becomes more sharply as the load increased.

关 键 词：柴油机 EGR NOx 烟度 

分 类 号：U464.172[机械工程—车辆工程]