Effects Of Methanol-Based Nanofluid Fuels On Combustion And Emissions Of A Diesel Methanol Dual Fuel(DMDF)Engine

The organic combination with nanoparticles can provide new ideas for the popularization and application of methanol alternative fuels in diesel engines.In this paper,different properties of nanoparticles（Ce O₂,Al₂O₃and Si O₂）were dispersed in methanol solution to produce a uniform and stable methanol-based nanofluid fuel,and then on the DMDF（diesel methanol dual fuel）engine test bench,different loads were studied Under the methanol replacement rate,the influence of each methanol-based nanofluid fuel on engine combustion and emissions performance has achieved the following main research results:First of all,through the base and the preparation of nano fluid fuel methanol observation found that will be used by sodium dodecyl benzene sulfonate（SDBS）and cetyl trimethyl ammonium bromide（CTAB）compound surface active agent,with 0.2%of the added than join respectively containing nanometer Ce O₂,Al₂O₃and Si O₂particles（≦100 ppm）in methanol solution,and after 1 hour of ultrasonic processing and mechanical stirring,fuel can be made by the nano fluid evenly in more than 15 days and have no obvious precipitation phenomenon.Then,through the analysis of the combustion performance test results,it is found that methanol-based Ce O₂nanofluid fuels with different addition ratios（25,50,100ppm）can improve combustion to a certain extent,and tend to be obvious as the addition ratio increases.The results show that when the addition rate of nano-Ce O₂is 100ppm,CA50 can be advanced 19.4%at a 50%methanol replacement rate and 90%load,and the fuel consumption rate can be reduced by 9.7%.In addition,methanol-based nano Al₂O₃and Si O₂fluid fuel（100 ppm）also has a significant improvement in combustion performance.Moreover,the difference between the three fluid fuels for the improvement rate of the brake thermal efficiency can reach about 9.6%,but the effect of nano Al₂O₃is particularly prominent for the shortening of the lag period,and it can reach 7.0%at 10%methanol replacement rate and 30%load.Nano-Si O₂has the best performance in increasing the maximum burst pressure and the peak value of instantaneous heat release rate,and can reach 5.8%and 8.6%at 50%methanol replacement rate and 90%load,respectively.Finally,through the analysis of the test results of the emission characteristics,it was found that the methanol-based Ce O₂nano-fluid fuel has an inhibitory effect on NO_X,HC,CO and soot emissions,and the reduction is most significant when the addition ratio is 100 ppm.The study found that at a 50%methanol substitution rate and a 10%load,the NOx specific emissions can be reduced by 30.8%,while at a 30%methanol substitution rate,soot emissions can be reduced by 26.9～68.7%.In addition,the reduction effect of nano Al₂O₃（100 ppm）on HC and CO emissions is significantly better than that of the other two nano additives.Its 50%methanol replacement rate can reduce the HC specific emissions by 79.3-88.8%,making the CO specific emissions are reduced by 58.6～90%.The reduction effect of nano-Si O₂in each emission is weaker than the other two.