Study On Combustion And Emission Characteristics Of A DI Diesel Engine Fueled With Biodiesel

Biodiesel is mainly composed by fatty acid-first ester and second ester, which is produced from vegetable oils or animal fats through the transesterification reaction. Its physical and chemical characteristics are similar with diesel. Because biodiesel is non-toxic, biodegradable and renewable, and can also reduce the harmful emissions from diesel engines, so it is a green and clean alternative fuel, and it attracts people's attention for its good environmental benefits gradually.Based on deeply understanding to the application of methods, the biodiesel's produce process and its physical and chemical characteristics, this paper studied the using performance of biodiesel and the concoction of biodiesel/diesel, and learned more about that biodiesel has the impact on diesel engine's combustion, dynamic, economy and emission characteristics.The results show that: Compared with the diesel, when the diesel engine fueled with pure biodiesel, the torque and power decreased slightly, the effective specific fuel consumption increased, the effective specific energy consumption increased slightly in low-speed small load, it had the similar with the diesel engine in other situations. When the engine fueled with biodiesel and the concoction of biodiesel/diesel, HC, CO and soot emissions reduced effectively, but NOX increased slightly. Compared with the original diesel engine, when engine burning biodiesel, the ignition delay period was shortened and the maximum eruptive pressure increased in all conditions. The maximum pressure increased in small and medium-sized load and decreased slightly in heavy load, the crank angle of the maximum pressure was ahead of schedule slightly. The highest rate of hest release increased in small and medium-sized load and decreased slightly in heavy load, the crank angle of the highest rate of hest release was ahead of schedule slightly. The combustion duration was extended slight in low-speed small load, was shortened slightly the high-speed large load. Without changing in the structure of the engine, diesel and biodiesel can be mixed in any proportion and the performance of the engine will not have a significant impact.