System of Measuring the Flame Propagation of a Spark Ignition Engine by High-speed Photographs Using PLZT Shutter

This paper describes a system of measuring the flame propagation of a spark ignition engine. A system using an electrooptical shutter known as the PLZT was developed and examined. Flame propagation photographs were taken by the still camera with the PLZT shutter. One characteristic of this shutter is rather lower transmissivity of light when opened. Another is slight transmissivity when closed. To solve these problems, a solution of sodium ethylate was added to the fuels to increase the brightness of the flame and a mechanical shutter was used together with the PLZT shutter. This system was examined and it was confirmed that the system satisfied the required specifications for the most part. Furthermore, an example of the flame propagation photographs and the cyclic variation of the flame area were shown when the swirl velocity was varied.