Experimental And Numerical Simulation Investigations On Combustion And Emission Characteristics Of Ethanol/N-butanol/Diesel Blended Fuel

With the increasingly stringent emission regulations and the rapid reduction of fossil fuel reserves,the use of clean alternative fuel has become one of the effective means to solve the environmental pollution and energy crises at the same time.Ethanol and n-butanol can effectively improve the combustion and emission performance of diesel engines as renewable and oxygen-containing fuels,so they have great application potential.In this paper,the effects of different blending ratios of ethanol/n-butanol/diesel blended fuel on the combustion performance,emission performance and economy of diesel engines were studied by means of experimental and numerical simulation.The effects of injection advance angle on combustion temperature in the cylinder,NO and Soot emissions were studied by changing the fuel injection starting point.In this paper,four different blended fuels were prepared according to the same oxygen contents of the blended fuel.The volume fractions of each blended fuel were 5%ethanol,13%n-butanol and 82%diesel;10%ethanol,5%n-butanol and 85%diesel;10%ethanol,18%n-butanol and 72%diesel;15%ethanol,10%n-butanol and 75%diesel respectively.And recorded as E5B13,E10B5,E10B18,E15B10.The intersolubility test of ethanol/n-butanol/diesel blended fuel was carried out,and the physical and chemical properties of blended fuel were analyzed.The results showed that ethanol/n-butanol/diesel blended fuels had good miscible stability.The oxygen content and vaporization latent heat value of the blended fuel were higher.The viscosity,density,cetane number and lower heating value of the blended fuel were lower.The effects of ethanol/n-butanol/diesel blended fuel on the combustion performance,emission performance and economy were investigated on a 186FA diesel engine.The results showed that under the constant engine speed and full load condition,the peak values of pressure,pressure rise rate and heat release rate of blended fuels were higher,and increased with the increase of the blending ratios of ethanol and n-butanol in the blended fuel.When the oxygen contents of the blended fuels were the same,the peak values of pressure,pressure rise rate and heat release rate of the blended fuel with a large proportion of ethanol were higher.Compared with diesel,the Soot emission of blended fuel decreased,and at medium and small loads,NO_X emission decreased and CO emission increased,while at full load,NO_X emission increased and CO emission decreased.The HC emission of E5B13 and E10B5 decreased,while E10B18 and E15B10 increased.When the oxygen contents of the blended fuels were the same,the Soot and NO_X emissions of the blended fuel with a large proportion of ethanol were lower,HC emission was higher,and at medium and small loads,CO emission was higher,while at full load,CO emission was lower.When the diesel engine was burned with ethanol/n-butanol/diesel blended fuel,the brake fuel consumption and the effective thermal efficiency increased.The simulation of the working process in the cylinder of ethanol/n-butanol/diesel blended fuel was carried out by the software FIRE,and the effects of the fuel injection advance angle on the combustion temperature,NO and Soot emissions of diesel and E15B10 were studied by changing the fuel injection starting point.The results showed that the peak of combustion temperature and the distribution range of high temperature area of blended fuel increased,and the distribution range of oxygen atom increased.The generation time of NO delayed,and the final generation amount and distribution range increased.The generation time of Soot delayed,and the final generation amount and distribution range decreased.With the increase of the injection advance angle,the peak of average temperature in the cylinder of diesel and E15B10increased,and the peak occurrence time advanced.The NO generated in advance,and the final generation amount increased.The Soot generated in advance,and the final generation amount decreased.Compared with diesel,changing the injection advance angle had more significant effects on the temperature,NO and Soot emissions of E15B10 blended fuel.