废气再循环对二甲醚/甲醇均质压燃燃烧过程影响的试验研究  

An Experimental Study on the Effects of EGR on HCCI Combustion Process of DME/Methanol Dual Fuels

作　　者：陈征[1] 尧命发[1] 郑尊清[1] 张波[1] 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《内燃机学报》2006年第2期116-121,共6页Transactions of Csice

基　　金：国家自然科学基金资助项目(50376046);国家重点基础研究发展规划资助项目(2001CB209021)

摘　　要：在单缸柴油机上进行了冷却废气再循环(EGR)对二甲醚(DME)/甲醇均质压燃(HCCI)燃烧过程影响的试验研究。结果表明,EGR对拓宽二甲醚/甲醇HCCI发动机的最大负荷作用不大;随着EGR率增大,主燃烧开始时刻和放热峰值明显后移,主燃烧持续期延长,放热峰值降低。EGR率为25%时的最大爆发压力比没有EGR时降低了近1.3 MPa,最大爆发压力出现的位置推迟了7°CA;EGR率增大,二甲醚/甲醇HCCI发动机的指示热效率升高。对应给定的EGR率,存在一个热效率较高的DME比例区间;HC和CO排放随EGR率的增大而增加,随DME比例的增加而降低,NOx排放接近于零。控制EGR率和DME比例是控制二甲醚/甲醇HCCI发动机燃烧过程、性能和排放的关键。Experimental study of the effects of cooled EGR on HCCI combustion process was carried out on a single-cylinder diesel engine fueled with DME/methanol. The results indicate that EGR rate has little influence on the maximum load of HCCI engine with DME/methanol. Increasing EGR rate will postpone the ignition timing of the main combustion, increasing the main combustion duration, and decreasing the peak value of heat release rate. Compared to those without EGR, the peak cylinder pressure decreases by nearly 1.3 MPa and the timing of peak pressure arriving postpones 7° CA for the case with 25 % of EGR. Meanwhile, increasing EGR rate will result in an increase in indicated thermal efficiency. For a given EGR rate, there exists the range for DME/methanol where higher thermal efficiency can be obtained. Both exhaust HC and CO emissions increase with the increase of EGR rate, while they decrease when the increase of DME proportion. NOx emission reaches almost zero level. The study shows that DME/methanol proportion and EGR rate are the key factors to control the combustion process, the performance and the emissions of HCCI engine fueled with DME/methanol dual fuels.

关 键 词：二甲醚 甲醇 均质压燃 废气再循环 燃烧过程 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]