在倒拖工况下对一台四气门火花点火式发动机缸内流场进行了试验研究。试验采用加长活塞结构及透明活塞顶，利用激光多普勒测速仪（ＬＤＡ），对气缸轴线的速度分布进行了测量。结果表明：在进气过程中，气缸内产生了双涡结构；在压缩过程初期，由于从进气门经过排气门流入气缸的气流产生的涡旋逐渐增强，而从进气门侧缸壁直接流入气缸的气流形成的反向涡旋逐渐减弱，最后演变成了单一大尺度的滚动涡流；在压缩过程中后期，滚流经历了发展、衰减、畸变和破碎的过程。为了进一步理解滚流形成、发展及演变过程，对缸内流动过程进行了多维数值模拟计算，计算结果与实测分析结果基本一致 The experimental research on the flow field of a four-valve spark-ignition engine cylinder was carried out under the inverted condition. The experiment uses an elongated piston structure and a transparent piston crown, and the velocity distribution of the cylinder axis is measured using a laser Doppler velocimeter (LDA). The results show that double vortex structure is generated in the cylinder during the intake process. At the beginning of the compression process, the vortex generated by the airflow from the intake valve to the cylinder through the exhaust valve gradually increases, The reverse vortex formed by the airflow directly into the cylinder gradually weakened and finally evolved into a single large-scale rolling vortex. In the latter part of the compression process, the tumble flow experienced the process of development, attenuation, distortion and fragmentation. In order to further understand the formation, development and evolution of tumble flow, multi-dimensional numerical simulation of in-cylinder flow was carried out. The calculation results are basically the same as those of actual measurement