Experimental Study Of Direct Injection Diesel Engine Operated On High Proportion DME-Biodiesel Blends

In recent years,the envirmental pollution and shortage of petroleum have become the problem of the word.At the same time,the emissions of vechels have become main pollution.Therefore the government attaches great importances on the clean energy's research.Dimethyl ether(DME)is one of the ideal alternative fuel.It can realize clean combustion when used in the cars.But DME has low viscosity,and high-pressure fuel injection system easily causes early wear and leakage,resulting duality of the life of the plunger significant decline,which restricts DME in the compression-ignition engine applications. Biodiesel has high viscosity,which added low percentage of biodiesel to DME is conducive to raising the viscosity of DME.So this topic introduced experiment of high proportion of DME fueled with low proportion of biodiesel on ZS 1110TD diesel engine.At the beginning,the article summed up the physico-chemical characteristics of dimethyl ether and biodiesel.The bio-diesel and 0 # diesel's viscosity have been measured in the different temperature.When in the temperature of 20℃, calculating the DB90 and DB80 viscosity of the blended fuel are 2.31 mm²/s and 1.47 mm²/s.It is higher than the viscosity of DME(0.15 mm²/s),and it is lower than the 0 # diesel viscosity(4.12 mm²/s).DB80 fuel's viscosity is very favorable for high pressure fuel injection system components for the lubrication.Since then,the high proportion of DME blended with low proportion of biodiesel was made experiments to optimize ZS1110TD engine.Adjusting plunger diameter fromφ9mm toφ10mm.Including injection of conditioning,hybrid fuel selection,the selection of supply advance angle,as well as the selection of injection pressure.By mixing different ratios of fuel in the ZS1110TD engine,in contrast characteristics of the mixed ratio of DB80,DB85 and DB90 choose DB80 selectivity for a better mix of fuels.By adjusting the angle of injection advance 19.4℃A,17℃A,15.2℃A and 13.3℃A in DB80 engine,and merit selection to supply advance angle at 17℃A.On this basis, injection pressure were adjusted to 18.5 MPa,16.5MPa,14.5MPa,and DB80 comparison of the characteristics,and merit a better selection injection pressure of 14.5 MPa.Finally,DB80 blended fuel was made experiment in the optimized ZS1110TD diesel engine,and comparative the power,economy and emissions with the original engine.The maximum torque is 64.4 N·m of DB80 engine at 1400 r/min.The torque is 6.4%higher than the original engine.The maximum power is 12.6 kW of DB80 engine at 2000 r/min.The power is 3.8%lower than the original engine.The fuel consumtion is 228g·(kW/h)^-1at external characteristics,which is 7.0%lower than the original engine.The torque and power has declined at high speed.The NOx emissions of DB80 engine are 62.5%lower than the average of the original diesel engine.The emissions HC are 75%lower than the original diesel engine.The emissions CO has increased. The carbon emissions are close to zero.The high proportion of DME blended with low proportion of biodiesel fuel used in the diesel engine has great practical significance for reduceing NOx and smoke emissions,and instead of the traditional fuel oil.