介绍了运用高速纹影摄影对火花点火发动机循环变动特性的研究.确定了纹影摄影胶片中可用于循环变动研究的部分,并对其进行了分析.结果表明:火花点火发动机的燃烧循环变动在燃烧一开始就已产生,并且表现为火焰中心、火焰速度、当量火焰半径、点火延迟时间、临界火焰半径、临界火焰速度等的变动. This paper introduces the research on the cycling characteristics of spark ignition engine by using high-speed schlieren photography, and makes a research on the part of the study on the cycle variation of the film for schlieren photography.It is shown that the combustion cycle of the spark ignition engine fluctuates in The combustion has taken place from the outset and is manifested by changes in the center of the flame, the flame velocity, the equivalent flame radius, the ignition delay time, the critical flame radius, the critical flame velocity, and the like.