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.
出处
《汽车技术》
北大核心
2009年第9期26-29,共4页
Automobile Technology
关键词
柴油机
EGR
NOx
烟度
Diesel engine,EGR,NOx,Smoke intensity
