柴油机燃用二甲醚-柴油混合燃料燃烧特性的试验研究

摘要

为了进一步研究柴油机燃用二甲醚-柴油混合燃料时的性能,测录了一台两缸四冲程柴油机在燃用D20混合燃料(二甲醚与柴油质量比为2:8)时,转速1700、2300 r/min情况下不同负荷的示功图,并对不同工况下的压力升高率、放热率以及缸内燃烧温度进行了计算.结果表明:在优化供油提前角后,柴油机燃用D20混合燃料时最大爆发压力平均下降10%,最早爆发压力对应的曲轴转角延迟2°CA,最大压力提升率相对降低约20%,燃烧放热始点延迟,最大燃烧温度下降80~100 K,但燃烧持续时间并未延长,放热曲线的重心更靠近上止点.%To further study the performance of the engine fueled with DME-diesel blends,the indicator diagrams of a two-cylinder four-stroke engine are recorded at 1 700 r/min and 2 300 r/min under different load,the heat release rate and the rate of pressure rise are calculated.T he results show that:w hen fueled the engine with D20 blend(Mass ratio of DME and diesel oil is 2:8)and optimizing the fuel supply ad-vance angle,the maximum cylinder pressure decreases by 10% averagely and its corresponding crank angle delays 2°CA,the maximum rate of pressure rise is relatively lowers about 20%,the beginning of heat re-lease delays,but combustion duration do not extend,and the centroid of heat release curves is closer to TDC(Top Dead Center),maximum combustion temperature drops 80-100 K.