低温预混合燃烧模式的燃烧与排放特性试验研究

发布时间：2018-03-15 04:24

本文选题：内然机　切入点：柴油机　出处：《内燃机工程》2016年04期 　论文类型：期刊论文

【摘要】：在一台电控高压共轨涡轮增压柴油机上研究了低温预混合燃烧模式对柴油机燃烧及排放的影响。采用早喷或晚喷预混方式,结合高废气再循环(EGR)率实现低温预混合燃烧,并研究了喷油正时、EGR、喷油压力和负荷率变化对预混燃烧模式的放热规律、排放特性和经济性的影响。研究结果表明:长的燃空预混合期是实现缸内预混燃烧的一个关键因素,中低负荷时,无论是早喷或晚喷预混模式,均具有长预混合期,短的扩散燃烧过程,兼具预混燃烧和低温燃烧的特征,高负荷下扩散燃烧比例增大;晚喷预混燃烧模式下,碳烟和氮氧化物(NO_x)排放同时获得降低,但低温燃烧和稀薄的混合气易导致燃烧不完全,喷油推迟较晚时引起HC和CO排放显著增加,并导致燃油消耗率增大;增加喷油压力可以同时改善碳烟、CO和HC排放,但是NOx排放增加,单纯提高喷射压力并不能获得性能的全面提高。
[Abstract]:The effect of low temperature premixed combustion mode on combustion and emission of an electrically controlled high pressure common-rail turbocharged diesel engine was studied. The low temperature premixed combustion was realized by using early injection or late injection premixing combined with high exhaust gas recirculation (EGR) rate. The effects of injection pressure and load rate on the heat release, emission characteristics and economy of premixed combustion mode are studied. The results show that the long pre-mixing period is a key factor to realize premixed combustion in cylinder. At medium and low load, both early injection and late injection premixing have long premixing period, short diffusion combustion process, both premixed combustion and low temperature combustion, and the diffusion combustion ratio increases under high load, while in late injection premixed combustion mode, Smoke and no _ x) emissions decreased simultaneously, but low temperature combustion and rarefied mixture resulted in incomplete combustion. When fuel injection was delayed, HC and CO emissions increased significantly, and fuel consumption increased. Increasing the injection pressure can improve the CO and HC emissions simultaneously, but the NOx emission is increased, and the performance can not be improved by simply increasing the injection pressure.
【作者单位】：华中科技大学能源与动力工程学院;湖北文理学院;
【基金】：国家自然科学基金项目(51176056)
【分类号】：TK421

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