SPECTROSCOPIC PROPERTIES OF UNBURNED SPECIES PRODUCED IN COMBUSTION PROCESSES

The reduction of pollutant emission from diesel engines can be achieved, by means of a suitable engine design and parameter regulations, needs the detailed knowledge of the combustion process. The aim of this work is to study the formation and the evolution of these species inside a combustion chamber of a diesel engine, using both optical "in situ" techniques and chemical and spectroscopic analysis. The optical techniques have a lot of advantages, when used to study very complex systems, in particular their high temporal and spatial resolution and non-intrusive nature. However they need a reliable interpretation in order to be used as speciation methods. On the contrary, the sampling and analysis of species collected in the engine, even presenting long time analytical procedure and many experimental difficulties in the sample collection, can give more qualitative and quantitative details on the evolution of organic products during the combustion cycle. In this work, chemical and spectroscopic analysis of the organic high molecular species produced was performed on a more controlled system, a premixed flame, to interpret the spectroscopic features obtained using optical techniques on a diesel engine.