Optical Combustion Measurements of a High Performance Two-Stroke Engine

This paper describes how an optical method has been used to investigate aspects of combustion in a high performance two-stroke engine.

The method involves measurement of the intensity of the light emitted at two wavelengths corresponding to the CH and C₂ radicals created in the combustion process on a cycle by cycle basis.

The effect of engine operating variables such as ignition timing and air-fuel ratio on the combustion light emission were examined. Comparisons are presented between the combustion light intensity measurements and conventional cylinder pressure based combustion analysis techniques.

Characteristics of the light emitted by these radicals are shown to be strongly related to cylinder pressure and air-fuel ratio.