Effects Of Injection Parameters On Emission Of Biodiesel Engine

The rapidly depleted fossil fuels and the more concerning of environmental crisis demand to search for alternative cleaner fuel. Biodiesel is mixture of fat acid methyl esters esterified from vegetable oils and animal fats with methanol or ethanol under the catalyst. Biodiesel physicochemical properties are similar to diesel and it’s an alternative renewable, sustainable and safe fuel. Currently biodiesel is mainly applied in unchanged diesel engine mixed with diesel in a small volume percent, but when large volume percent or pure biodiesel are used, diesel engine need to adjusted. Based on above, this article researched the injection parameters’effects on the combustion and emission characteristics of biodiesel engine, this will be meaningful for more application of biodiesel.The fatty acid methyl esters(FAME) varied in different soured biodiesel, this article tested the components and corresponding percentage of biodiesel sourced from soybean and waste-cooking oil using the method of Gas chromatography-mass spectrometry(GC-MS). Based on the results, estimated the critical data and physical properties of FAME and biodiesel including enthalpy 、liquid viscosity 、latent heat、vapor pressure、surface tension and thermal conductivity with empirical formulas. Added these data to the fuelib of KIVA3V and debugged the program, preparing for the following simulations.The simulation in this article selected the KH-RT break model, for the difference between diesel and biodiesel, there’s need to adjust the model constant. Adjusted the break constants Crt and B2 of KH-RT model, results found that Crt has greater effect on spray characteristics, as Crt decrease, the Sauter Mean Diameter(SMD) become smaller, while the liquid penetration change little. In the following simulation, set Crt equal to 0.1 and B2 to 40.KIVA3V simulated the biodiesel emission characteristics under different injection timing. Results revealed that as the injection timing advanced in a range, the mean in cylinder pressure and temperature become higher, also the released heat and the heat release rate. When the injection timing is 13℃ A before top dead center(BTDC), the released heat is largest and the release rate is fastest and the brake mean pressure is largest. CO final emission decreased with the advance of injection timing, but Soot emission change little and NOX emission increase.Keeping the brake mean power as a constant, researched the injection pressure’s effects on the performance and emission of biodiesel engine, found that as the injection duration become shorter, injection pressure increase, the brake fuel consumption of the both fuel decrease, but the lower margin of biodiesel is smaller than diesel and under the same injection duration, the brake fuel consumption of biodiesel is higher than diesel. As the duration becomes shorter, the final emission of CO and Soot decrease and lower than diesel at the same duration, but the NOX emission increase and higher than diesel.