Abstract
In order to reduce soot emitted from Direct Injection Spark Ignition (DISI) engine, the key is to figure out a soot formation process which is timing during combustion and the location in a cylinder. In this study, the soot formation process was revealed by a piston fuel film analysis and soot spatial distribution analysis which were measured by an optically accessible engine. High density of soot is not located on the piston cavity but in the special area of the exhaust side combustion chamber during fast idle operation. In addition, the soot formation continues to increase as time goes on.
