论文部分内容阅读
在倒拖工况下对四气门火花点火式发动机缸内空气运动进行了实验研究和分析 .采用加长活塞结构及透明活塞顶 ,利用激光多普勒测速仪 (L DA) ,分别对气缸轴线上、燃烧室内和气缸上部两个平面上的速度进行了测量 ,结果表明 :在进气过程中 ,缸内产生了双涡结构 ;在压缩过程初期 ,由于从进气门流向排气门侧的滚动涡旋逐渐增强 ,而另一侧的反向涡旋逐渐减弱 ,形成了单一大尺度的滚动涡流 ;在压缩过程中后期 ,滚流经历了加强、衰减、变形和破碎的过程 .
The air movement in four-valve spark-ignited engine was studied experimentally under inverted working condition.Using extended piston structure and transparent piston top, laser Doppler velocimetry (L DA) , The combustion chamber and the cylinder on the upper two planes were measured, the results show that: in the intake process, the cylinder has a double vortex structure; early in the compression process, due to the flow from the intake valve to the exhaust valve side of the scroll The vortex increases gradually, while the reverse vortex gradually weakens on the other side, forming a single large-scale rolling vortex. In the latter part of the compression process, the tumble flow experiences strengthening, decay, deformation and crushing.