| Energy shortage and environmental pollution are the major problems faced by human development.Excessive consumption of oil caused Greenhouse Effect,Haze and other eissues.The physical and chemical characteristics of biodiesel are similar with diesel.Biodiesel is non-toxic,biodegradable and renewable,and can also reduce the harmful emissions,so it attracts people’s attention.Experts in both china and abroad have done a lot of research on biodiesel,which proves that the use of biodiesel and its blends with diesel fuel can reduce carbon emissions,But there are few studies on the emission of ultrafine particles.In this paper,the cylinder pressure of biodiesel and diesel oil was tested on a high pressure common rail diesel engine.The heat release rate was calculated.The particle size distribution and number concentration of ultrafine particles were measured.Based on the combustion characteristics,the emission and particle size distribution of ultrafine particles were studied.Experimental results show:Compared with diesel fuel,the maximum cylinder pressure of the diesel engine fueled with biodiesel decreased in medium-sized load and heavy load,and was equivalent with diesel in other loads;The maximum instantaneous heat release rate increased slightly in small and partial load and decreased slightly in medium-sized load and heavy load.Compared with the original diesel engine,in all operating conditions,the fuel injection beginning was ahead of schedule,the fuel injection end was delayed,and the injection duration was longer;The rapid combustion period was shortened in small and partial load,but prolonged in medium-sized load and heavy load;And the combustion duration was shortened in all operating conditions.Compared with diesel fuel,Sub-220 nm particulate number concentration decreased in most of the working conditions;the volume concentration decreased in all operating conditions.The number concentration of ultrafine particles increased with small load and partial load in low-speed small and partial load,and decreased significantly in high –speed;the volume concentration decreased in all operating conditions. |
