松油掺混燃料的喷雾及燃烧排放特性试验

Experiment on Spray Visualization of Pine Oil Blends and Their Combustion and Emission Characteristics

为探究松油作为柴油机替代燃料的可行性,在定容弹中结合高速摄影技术对松油掺混比例为20%,、40%,和50%,的柴油/松油混合燃料在不同喷射压力及背压下的宏观喷雾特性进行可视化研究;同时基于一台4缸涡轮增压柴油机,研究掺混燃料在不同负荷下的燃烧和排放特性.结果表明:随喷射压力及背压的改变,4种燃料喷雾特性的变化规律一致;相同条件下松油掺混燃料的喷雾锥角、贯穿距及油束面积均比柴油大,且松油掺混比越大,雾化效果越好.在试验负荷范围内,松油掺混燃料的有效燃油消耗率、最大压力升高率比柴油略大;在全负荷工况下50%,掺混燃料的转矩较柴油仅降低2%,表明松油可提供与柴油相当的动力输出.掺混燃料在低负荷时的NO_x、CO和THC排放均高于柴油,中、高负荷时掺混燃料的CO及THC排放低于柴油,NO_x排放与柴油差别不大;通过增加松油掺混比例可以大幅降低碳烟的排放.

To study the feasibility of utilizing pine oil as an alternative fuel for diesel engines, high-speed photograph technique was applied to visually investigate the macroscopic spray characteristics of diesel/pine oil blends in a constant volume chamber at different injection pressures and ambient pressures. The study was conducted under the pine oil blending ratios of 20%, 40% and 50%, respectively. Combustion and emission characteristics of the blended fuels were studied on a four-cylinder turbocharged diesel engine. Results show that the spray characteristics of pine oil blends are similar to conventional diesel fuel under the same variation of injection pressure and ambient pressure. But these macroscopic spray parameters of pine oil such as spray cone angle, spray tip penetration and fuel jet area are larger than those of diesel fuel. In addition, with the increment of pine oil blending ratios, the atomization quality of the blended fuels becomes better. For pine oil blends, the brake specific fuel consumption and the maximum pressure rise rate are slightly higher compared with the diesel fuel. Under full load conditions, the maximum torque for the pine oil blend with a ratio of 50% is only 2% lower than that of the diesel fuel, indicating that pine oil and diesel can provide equivalent power output. NOx, CO and THC emissions of the blended fuels are higher than those of diesel fuel under low load conditions. Under high and middle load conditions, however, the conventional diesel fuel has higher CO and THC emissions than the blended fuels, and its NOx emissions are almost the same with the blended fuels. Furthermore, soot emission scan significantly reduce by increasing the blend proportion of pine oil.