超多喷孔喷油嘴早喷射低温燃烧试验研究  

Experiment Study on Early Injection Low Temperature Combustion of Ultra-Multi-Hole Nozzle

作　　者：缪雪龙[1] 郑金保[1] 洪建海[1] 王先勇[1] 居钰生[1] 陈希颖[1] 

机构地区：[1]中国一汽无锡油泵油嘴研究所,江苏无锡214063

出　　处：《现代车用动力》2012年第4期1-6,17,共7页Modern Vehicle Power

摘　　要：进行了早喷射喷油定时、废气再循环(EGR)率和喷油压力实现低温燃烧降低排放的试验研究。通过缸内压力和燃烧排放数据的采集、处理,分析这些参数对放热规律、滞燃期、燃烧重心、排放等特性的影响。早喷射可以实现低温燃烧,但与晚喷射相比,早喷射的滞燃期稍短,需要更大的EGR率来适当延长滞燃期并降低燃烧温度,最优排放点与原机相比烟度下降了63%,NOx降低了81%,但油耗比原机升高了6%。除了压缩比降低的原因,燃烧始点在上止点前造成的传热损失增大,增大喷油压力和提前喷油会导致燃油喷射到活塞顶面和气缸壁面,以及增大EGR率导致的增压压力和混合气氧气含量下降引起的燃烧效率下降等都可能是油耗升高的原因。早喷射与晚喷射相比,燃烧更稳定,放热率峰值较高,但是早喷射的最大压力升高比较大,甚至会超过2 MPa/(°)。Experimental study was carried out to investigate the effect of high EGR rate coupled with high fuel injection pressure on the low temperature combustion diesel engine in the condition of early fuel injection.Combustion characteristics were analyzed based on the data of cylinder pressure and emissions.The low temperature combustion could be realized by the combination of the early fuel injection and high EGR rate.The emissions of soot and NOx reduced by 63% and 81% respectively than those of the original diesel engine,but the fuel consumption increased by 6%.The reasons may be as follows.The fuel spray maybe impinge on the cylinder wall due to the early fuel injection and high fuel injection pressure,the O2 concentration reduce due to the high EGR rate,the heat loss will increase because the start of combustion is ahead of TDC.In addition,the compression ratio is reduced.The early fuel injection has features of the rapid heat release and steady combustion,but has a high maximum pressure rise,even more than 2 MPa/(°).

关 键 词：早喷射 低温燃烧 柴油机 排放 

分 类 号：TK423.8[动力工程及工程热物理—动力机械及工程]