Study On The Experimental And Numerical Simulation Of Diesel Engine Fueled With N-butanol/Diesel Blends

With the environmental problem and energy crisis becoming prominent increasingly, the development of alternative fuel has become one of the effective ways to energy-saving and emission-reduction of internal combustion engine. The experiment of domestic and foreign research showed that n-butanol could reduce the soot emission significantly as the second generation biofuel. This paper mainly research the influence of different n-butanol proportion and different swirl ratio on engine dynamic performance, emission performance and economy performance by the combination of engine bench experiment and numerical simulation.The intersolubility experiment showed that under normal temperature and pressure, the n-butanol and diesel fuel could be blended quickly without any cosolvent, the intersolubility and stability were fine. The blended fuels of B40(the n-butanol volume proportion was 40%) did not appear layering phenomenon within 7 days.The experiment of combustion performance showed that, under 100% load condition, in the range of B0~B30, both of the ignition delay period of blended fuels and maximum explosion pressure increased gradually. Under the rated condition, the maximum explosion pressure of the B40 blended fuels was 10.5% lower than the pure diesel fuel, and the power was reduced, which could not meet the requirement of dynamic.The experiment of emission performance showed that, the Soot and NO emission of blended fuels were lower slightly than the pure diesel fuel under the light load(10%, 25%). Under the medium load(50%), with the increase of n-butanol proportion, the Soot emission of blended fuels reduced gradually, and the NO emission kept unchanged basically. Under the high load(75%, 100%) condition, with the increase of n-butanol proportion, the NO emission increased, the Soot emission reduced significantly. Under the same load condition, with the increase of n-butanol proportion, the emission of HC decreased firstly and then increased. Among them, the HC emission of B15 blended fuels was the lowest. Under the high load condition, the CO emission decreased gradually with the increase of n-butanol proportion, the CO emission increased gradually under the light and medium loads.The experiment of economic performance showed that, the fuel consumption rates of B5~B20 blended fuels did not obvious increase markedly than the pure diesel fuel. The fuel consumption rate of B30 blended fuels was 4.7% higher than the pure diesel fuel, and the increase range of B40 was 23%.Due to the main operation of the engine was in the full load condition, so the B30 was the optimal scheme.The results of numerical simulation showed that, under the condition of pure diesel fuel, with the increase of swirl ratio, the average pressure peak, the maximum average temperature, the cumulative heat release and the NO emission were increased gradually, the Soot emission decreased gradually. Under the condition of B20, with the increase of swirl ratio, the average pressure peak and the maximum average temperature increased gradually, while the cumulative heat release and the soot emission decreased gradually, NO emission increased firstly and then decreased. Under the condition of B30, with the increase of swirl ratio, the average pressure peak, the maximum average temperature, the NO emission increased firstly and then reduced, the cumulative heat release and the soot emission decreased gradually. By comparing and analyzing of numerical simulation results, from the aspects of enhancing dynamic and reducing emission, under the condition of pure diesel fuel, SR1(swirl ratio was 1) was the optimal scheme; under the condition of B20 and B30, SR3.4 was the optimal scheme.