An experimental study of HCCI-DI combustion and emissions in a diesel engine with dual fuel
An experimental study of HCCI-DI combustion and emissions in a diesel engine with dual fuel
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DOI：
10.1016/j.ijthermalsci.2007.10.007
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发表时间：
2008-09
影响因子：
4.5
通讯作者：
Junjun Ma;Xingcai Lu;Libin Ji;Zhen Huang
中科院分区：
文献类型：
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作者：
Junjun Ma;Xingcai Lu;Libin Ji;Zhen Huang
在一台单缸柴油机上进行了进气道喷射正庚烷均质压燃（HCCI）与缸内直喷（DI）联合燃烧的试验研究。通过调节预混合正庚烷和直喷柴油的量，在发动机保持恒转速的情况下，在很宽的负荷范围内获得不同的预混合比。研究了预混比和直喷提前角对HCCI直喷燃烧特性和排放的影响。为了评价HCCI直喷燃烧的特点，对常规柴油机和HCCI发动机的性能进行了对比研究。重点分析了复合燃烧过程。结果表明，部分预混能显著降低NOx排放，当预混比小于0.3时，NOx排放随预混比的增加呈下降趋势，但随着预混比的增加，NOx排放又有明显的增加趋势。在低转速条件下，柴油机的碳烟排放与原型柴油机相当，NOx和碳烟的内在平衡并不明显。此外，还分析了rp对CO和UHC排放的影响。结果还表明，HCCI直喷燃烧能有效地提高柴油机在中低负荷时的指示热效率。
An experimental study of port injected n-heptane homogeneous charge compression ignition (HCCI) in combination with in-cylinder diesel fuel direct injection (DI) was conducted on a single cylinder diesel engine. By adjusting the quantities of premixed n-heptane as well as the direct injected diesel fuel, different premixed ratios were obtained over a wide range of load conditions while the test engine was kept at a constant speed. The effects of premixed ratio (rp) and direct injection timing on HCCI-DI combustion characteristics and emissions were investigated. In order to evaluate the traits of HCCI-DI combustion, the conventional diesel and HCCI engine performances were presented to be compared with their results. Furthermore, special emphasis was put on the combined combustion process analysis. It can be found that the NOx emissions decreased dramatically with partial premixing and it exhibited a descending trend as a function of rpincrease when the rpwas lower than 0.3, but it showed a great tendency to increase when the premixed ratio was higher. The inherent trade-off of NOx and soot was not obvious since the soot emissions remained at the same level of the prototype diesel engine under the condition of lower rp. Moreover, the influence of rpon the CO and UHC emissions was assessed. The results also revealed that the HCCI-DI combustion could effectively improve the indicated thermal efficiency of diesel engine at low to medium loads.