Study Of Spray Characteristics And Engine Performance Of Tung Oil-diesel-ethanol Micro-emulsions

The reserves of Oil is limited and the harmful emissions cause by burning fossil fuels making the development of automotive cleaning alternative fuels more and more important.As a Bio-fuel,vegetable oil which is derived from the plant.As we all know,there are many kinds of oil plants in the world,which makes the vegetable oil sources are very wide and varied.Most of the oil-producing plants have a short growth cycle and are easily cultivated,and the using of vegetable oil is extensive,it is an economical alternative fuel.In this paper,Tung oil was selected as the research object,Tung oil is extracted from the seeds of Tung tree.Tung oil-diesel-ethanol micro-emulsions of the different proportions were prepared.The main physical and chemical parameters of the blend fuels were determined by GB testing methods.Use the high-speed camera system and Malvern Instruments Spraytec laser diffraction system to test the spray characteristics of the micro-emulsified fuels.On the bases of the properties and spray characteristics of the Tung oil micro emulsion fuels,and then tested them on diesel engine.The test results show that:Physical and chemical properties: 1.Oleic acid and N-butanol mixture can be used as an effective surfactant to prepare a stable and homogenous micro-emulsion of tung oil,diesel and aqueous ethanol;2.Micro-emulsified fuel's density,kinematic viscosity and the surface tension are obviously lower than that of Tung oil,With the increase of the proportion of ethanol,Micro-emulsified fuel's Calorie value and air-fuel ratio were reduced;3.The density and viscosity approached that of diesel with the increase of ethanol volume fraction up to 20 % and Tung oil volume fraction up to 30%.Spray characteristics: 1.Diesel fuel's spray is looser than the micro-emulsified fuel;2.With the increasing of Tung oil blending,the spray cone angle of Micro-emulsion fuel decreases and that the spray penetration increase gradually;3.The micro-emulsified fuel's peak of the size and number distribution curve for spray droplet gradually reduce than that of diesel oil,moreover,the cumulative volume distribution curve of spray droplet shift towards the direction of large liquid droplet,the number of the small droplets decreased,the number of large particles increased correspondingly.The engine performance: 1.The use of micro-emulsion fuel will make the effective specific fuel is higher than that use of diesel oil,while the effective energy consumption rate are slightly lower than the diesel oil;2.The NOX emissions of micro-emulsion fuel were almost similar to those of diesel in the small and medium load while slightly higher in high speed and heavy load;3.The CO and HC emissions of micro-emulsion fuel of blending 30% Tung oil in the entire load range are close to diesel,micro-emulsion fuel of blending 50% tung oil were higher than those of diesel in the small and medium load while slightly lower in high speed and heavy load;3.micro-emulsion fuel can significantly reduce the engine smoke emissions;The results show that using Tung oil in micro emulsion can solve the problems of high viscosity and poor volatile.The characteristics of micro-emulsion fuel of which the proportion of Tung oil in the base oil is 30% and the proportion of the ethanol in the micro-emulsion fuel is 20% is similar to those of diesel oil.