机油液滴诱发早燃的快速压缩机试验研究

Experiment Study on Oil Droplet Induced Pre-Ignition in RCM

早燃是在火花点火内燃机中的一种非正常燃烧现象,容易诱发超级爆震并破坏发动机。本文在快速压缩机中引入机油液滴,研究了机油液滴对异辛烷可燃混合气着火特性的影响,同步采集了压力数据和燃烧图像。试验结果表明,高温高压异辛烷可燃混合气中的机油液滴能够自燃并点燃周围混合气,其火焰传播特征与火花点火接近。采用3种市场常用发动机机油引入燃烧室均出现了自燃现象,提高压缩终点压力会使机油液滴的着火延迟时间缩短。

Pre-ignition is an abnormal combustion phenomenon in the spark ignition internal combustion engine,which may lead to super-knock and engine destruction.In this paper,the oil droplet was introduced into the rapid compression machine（RCM） to investigate the effect of oil droplet on the ignition of iso-octane mixture.The pressure traces and combustion images were acquired synchronously.According to the test result,the oil droplet in the high temperature high pressure iso-octane mixture could self-ignite and caused the ignition of the ambient iso-octane mixture,whose flame propagation is similar to the case of spark ignition.Three kinds of different commercial engine oil were tested and they all self-ignited in the combustion chamber.Moreover,the ignition delay decreased with the pressure at the end of compression increasing.