Investigation of Fuel Effects on Soot Formation Using Forward Illumination Light Extinction (FILE) Technique

In-cylinder soot formation processes of Environmentally Controlled Diesel (ECD), Diesel #2 and Tetradecane were studied with the newly developed forward illumination light extinction (FILE) soot measurement technique. Quantitative soot measurement was achieved in the constant-volume spray chamber with the proper treatment of chamber window reflection and flame radiation when applying the FILE technique. A better understanding of the soot formation process of ECD combustion under the typical engine conditions was obtained based on FILE soot measurement and flame emission measurement. Diesel #2 with higher sulfur content demonstrates a similar combustion process as ECD but more soot is generated within combustion. In contrast, much lower soot amount was found within the flame of Tetradecane. However, during the last soot oxidation period, the differences were small for all fuels.