Analysis of Combustion and Emission Characteristics of a Diesel Engine Fueled with Ternary Micro-Emulsion Blends

In order to make diesel and methanol miscible,and to increase fuel oxygen content to control soot emissions,n-pentanol was used as a co-solvent to prepare the ternary micro-emulsion fuels blended with diesel,n-pentanol and methanol.The combustion pressure and emission characteristics were tested at 1 400 r/min on an electronically controlled high pressure common rail diesel engine.The instantaneous that release rate and combustion temperature were calculated and compared with the straight diesel operation.Results show that methanol can be miscible with diesel and n-pentanol at a certain ratio,and the ratio of mutual solubility increases with the rise of temperature.Compared with the straight diesel operation,the increase of the oxygen content of the blended fuels prolongs the ignition delay and shortens the combustion duration,thus increasing the park combustion temperature.At low and medium loads,the peak combustion heat release rate rises and then decreased at high loads coupled to the increase of diffusion combustion intensity.The fuel consumption of the blended fuel increases with the rise of methanol content,but will improve with thermal efficiency at high loads.The use of three oxygenated fuels results in increased CO emissions at low loads and decreased CO emissions at high loads besides increased HC and NO x emissions and significantly reduced soot emissions.