Compression and End-Gas Temperatures from Iodine Absorption Spectra

THIS paper discusses a method of measuring compression temperature by means of the absorption of light.

An optical-electronic system measures the change in color of a trace of iodine gas that has been added to the intake mixture. From these measurements the temperature of the iodine and by inference, the temperature of the gases, is determined.

The apparatus used is described briefly and the test results obtained in measuring compression and end-gas temperatures in a spark-ignition engine are also presented.