Abstract: The effects of biodiesel and dimethyl carbonate (DMC) as oxygenate additives on combustion process power, output  and soot emission were investigated on an engine test bench to reduce the soot emission from a heavy duty diesel engine.  The test results show that the pressure curve in cylinder moves backward and the peak value drops when the proportion of the oxygenate fuel increases. The heat release rate curve moves backward either, but the peak value of the heat release increases. The oxygenated fuels decrease particulate matter (PM) emission. The addition of torque at full load biodiesel and DMC leads to less PM but more NOx emission. The engine drops about 5% with volume fraction 20% of biodiesel and 10% of DMC. After adjustment of the maximum fuel feeding, the power using oxygenate blends may be recovered to original value using pure diesel but the soot emission decreased 54.5%.

Key words: diesel engine, biodiesel, dimethyl carbonate (DMC), soot emission