【摘要】 在一台压缩比为16.5的2135柴油机上实现了纯二甲醚(DME)的均质充量压缩燃烧(HCCI)燃烧方式。试验结果表明,DME的HCCI燃烧模式不但可以实现无烟燃烧,还可以有效控制发动机NOx排放,使其接近于0。在试验负荷范围内,CO排放随负荷增加而降低;HC的排放随负荷变化不大。对DME的HCCI燃烧机理等进行的研究表明,由于纯DME的着火比较早(上止点前28°CA左右),发动机只能在中低负荷较小范围内运行。为了扩展发动机运行工况,控制HCCI着火,通过在DME中添加LPG以降低燃料十六烷值的方法和在进气中加入惰性气体CO2的方法来改进和控制HCCI的燃烧。试验表明以上两种方法都可以有效的控制HCCI燃烧,拓展HCCI发动机运转范围。更多还原

【Abstract】 A 2135 C.I. engine was modified to work at the DME HCCI combustion mode with compression ratio of 16.5. The experimental results showed that DME HCCI combustion could give almost zero NO_x emission and smokeless behaviors. Within the narrow range of A/F ratio, CO emission decreased with the increase of engine load, while little variation in HC emissions presented. The HCCI combustion of DME gives an obvious two-stage combustion characteristic. Since the early ignition of DME （28° CA BTDC）, the engine can be operated with a limited low-medium loads. In order to control the ignition timing and extend the operating range, LPG was added in DME to lowering the cetane number or introducing CO₂ into the intake fresh air. The results showed that these two approaches could effectively control the HCCI combustion and extend engine operating range.更多还原