异辛烷/柴油双燃料分层充质压缩着火燃烧和排放特性  

Combustion and Emission Characteristics of Stratified Charge Compression Ignition Fueled with Iso-octane/diesel Dual Fuel

作　　者：吉丽斌[1] 吕兴才[1] 马骏骏[1] 黄震[1] 

机构地区：[1]上海交通大学动力机械及工程教育部重点实验室,上海200240

出　　处：《上海交通大学学报》2008年第3期375-380,384,共7页Journal of Shanghai Jiaotong University

基　　金：国家重点基础研究发展规划(973)项目(2007CB210007);上海市重大基础研究项目(05DJ14002);上海市自然科学基金资助项目(06ZR14045)

摘　　要：在一台单缸发动机上进行了双燃料分层充质压缩着火(SCCI)燃烧的试验研究.分析了异辛烷作为预喷射燃料,柴油作为缸内直喷燃料的SCCI着火方式和燃烧过程,并通过固定直喷入缸内的柴油当量比ΦD,研究不同异辛烷预喷射当量比ΦP对SCCI燃烧和排放特性的影响.研究表明:SCCI燃烧出现两阶段放热;ΦP对燃烧和排放特性的影响存在一个临界值,且ΦD固定值增大,该临界值降低.对燃烧特性的分析发现:当ΦP高于临界值时,异辛烷的着火延迟明显缩短,其放热峰值显著增大;整个SCCI的燃烧速率、缸内最大压力和最高温度迅速提高,燃烧持续期几乎保持不变,热效率显著改善.对排放的研究发现:ΦP增大时,HC和CO排放先增大,但当ΦP高于临界值时,HC和CO排放逐渐减少;NOx和碳烟的排放随ΦP的增大而增大,但当ΦP高于临界值时,增大速率显著加快.Abstract. Experiments on stratified charge compression ignition （SCCI） combustion of iso-octane/diesel dual fuel were carried out with a single-cylinder modified engine. Iso-octane, which was supplied by a port fuel injector from the intake manifold, was premixed with air. Near top dead center （TDC）, a small amount of diesel was directly injected into the combustion chamber to achieve fuel-rich area. Thus the stratification not only in mixture homogeneity but also in gas composition was achieved. The ignition and combustion process of SCCI combustion were analyzed, and the influence of iso-octane equivalence ratio （Фp） was investigated when the diesel amount （ФD） was fixed. The experimental results show that, SCCI combustion exhibits two stages of heat release, and a critical value of ФP exists when affecting the SCCI combustion and emission characteristics. Furthermore, while the fixed value of ФD increases, this critical value decreases. The analysis of combustion characteristics shows that, the ignition delay of iso-octane shortens, the peak value of heat release rate of iso-octane increases, the total combustion rate accelerates,the maximum temperature and pressure rise and the indicated efficiency improves while Фp is bigger than critical value. The analysis of emissions shows that, HC and CO emissions increase with the increase of Фp at first, but while Фp is upon critical value, both of them start to decrease. NOx and soot emissions increase with the increase of Фp all the time, however the increasing rate accelerates while Фp is upon critical value.

关 键 词：分层充质压缩着火 双燃料 燃烧 排放 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]