燃烧室
点火系统
燃烧
点火正时
均质压燃
SPARK(编程语言)
火花点火发动机
稀烧
发动机爆震
机械
核工程
喷射(流体)
材料科学
化学
热力学
物理
氮氧化物
工程类
计算机科学
有机化学
程序设计语言
作者
Yiguo Xue,Pengcheng Wang,Qingwu Zhao,Shaobo Ji,Cheng Yong,Wei Yin
标识
DOI:10.1177/14680874231162919
摘要
An enhanced combustion concept, pre-chamber jet ignition can provide high ignition energy and a wide dispersion of ignition sources, thus improving combustion performance and realizing stable lean combustion. However, the ignition performance of the pre-chamber jets depends strongly on the pre-chamber combustion process and is sensitive to many factors. Therefore, this paper will explore the impact of spark timing on the pre-chamber combustion, turbulent jet characteristics, and main chamber combustion performance by CFD simulation based on an active pre-chamber natural gas engine. The in-cylinder flow and combustion processes of the engine are calculated with the fuel-air equivalence ratio of the main chamber maintained at 0.5, and the spark timing varied from 684°CA to 708°CA with a step of 3°CA (compression top dead center is 720°CA). The results show that, in the present engine operating point, the pre-chamber combustion heat release rate is improved when the spark timing is retarded from 696°CA to 705°CA, and the injection velocity of the pre-chamber jet accordingly increases. As the spark timing continues to be delayed until 708°CA, the pre-chamber combustion deteriorates, and the injection velocity of the pre-chamber jet decreases. Under the combustion phase CA50 no more than 725°CA and the combustion duration CA5-90 fixed around 30°CA, the IMEP will maintain a relatively stable value when the spark timing is delayed from 693°CA to 705°CA, in the meantime, the NOx emission decreases with the delay of spark timing. Therefore, on the premise of ensuring engine power performance, it is a feasible scheme to delay spark timing to reduce NOx emission for the natural gas engine with an active pre-chamber.
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