Biodiesel Preparation by Transesterification Persian lilac Oil Seeds and Investigating the Effects of Utilizing it in a Diesel Engine on Exhaust Pollutants

Biodiesl is a renewable fuel that can be used alone or combined with diesel fuel in diesel engines. In this research biodiesel was synthesized using Persian lilac oil seeds. Biodiesel was purified by washing it with water and some of its physical properties was measured. Then it was mixed at 10, 20 and 30% proportion with regular diesel fuel and was tested in a four-cylinder diesel engine. The exhaust pollutants including CO, CO2, unburned carbohydrates (HC), NOx and the temperature of the exhaust gases were determined at three engine loadings of 200, 250, and 300 N.m and at six engine speeds ranging from 1300 to 1800 rpm. The measured pollutants were compared with those obtained from a regular diesel fuel. The results indicate that with increase in the percentage of biodiesel the emission of CO and HC and the temperature of the exhaust gases decreased but the CO2 and NOx emissions increased. By increasing the speed of the engine the emission of CO, CO2, HC and the temperature of the exhaust gases increased but the amount of NOx deceased.  Increase in the engine loading caused a decrease in NOx emission but other measured pollutant and the temperature of the exhaust gases increased.