柴油机起动过程缸内窜机油现象的可视化研究

摘要

在单缸机上利用内窥镜技术观察到了起动过程中缸内有窜机油的现象.采用图像分析和试验验证相结合的方法,分析了缸内窜机油现象发生的原因,研究了转速和进气压力对柴油机起动倒拖工况下缸内窜机油现象的影响,研究了起动着火运行时缸内的窜机油现象以及炭烟排放特性.研究表明:柴油机高转速起动倒拖工况下,在压缩上止点前后以及排气上止点后均有机油窜入缸内;当转速升高时,窜入缸内的机油量增加;当缸内压力升高时,窜入缸内的机油量减少;在起动着火过程中,运行初期缸内出现窜机油现象,随着发动机运行时间增加,窜机油现象消失,炭烟减少.%The phenomenon of lubrication oil flowing inside cylinder was observed by using endoscope technology on a single-cylinder engine .Adopting the methods of image analysis and experimental verification ,the reasons of that phenomenon were analyzed and the influences of speed and intake pressure on in-cylinder oil flow problem were studied under the motored condi-tion during the start process .In addition , the in-cylinder oil flow and soot emission were researched during the operation process after start .The results show that the phenomenon exists before and after the top dead center or after the bottom dead center of diesel engine when starting engine by dragging at a high speed .The amount of lubrication oil flowing inside cylinder increases when the speed increases and decreases when the cylinder pressure increases .The in-cylinder oil flow phenomenon during the earlier period of start disappeared with the increase of running time and the soot emission decreases .