EFFECTS OF FUEL PROPERTIES ON EXHAUST EMISSION FROM DI DIESEL-ENGINE

Exhaust emissions (HC, CO, NOx, PM, and PAH (polycyclic aromatic hydro carbons in PM)) from a commercial DI diesel engine were measured for p etroleum-derived fuels with a wide range of fuel properties. Fuel prop erties such as cetane number, aromatic content and type, and distillat ion temperature were adjusted to be independent from each other. The t est results showed that total aromatic content was the controlling fac tor for NOx emission, and PM emission mainly depended on polycyclic ar omatic content in the fuel. The increases in PM emission with increase in aromatics was mainly caused by the increase in SOF emission. Both of NOx and PM emissions were seldom affected by cetane number and 90% distillation temperature. Therefore, chemical characteristics of fuel are the controlling factor for NOx and PM emission, not the physical p roperties. The amount of sulfate in PM proportionally increased with i ncrease in sulfur content of fuel. PAK emission was evaluated by analy zing SOF using a high performance liquid chromatography with a chemilu minesence detector. Also, the PAH highly depended on aromatic content, and the emission characteristics caused by aromatics was quite simila r to PM emission.