柴油机燃用二甲醚-柴油混合燃料燃烧特性的试验研究

Experimental Study on the Combustion Characteristics of the Engine Fueled with DME-Diesel Blends

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1 700、2 300r/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80~100K,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.The results show that：when fueled the engine with D20 blend（Mass ratio of DME and diesel oil is 2∶8）and optimizing the fuel supply advance 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 release 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.