Effect of fuel injection timing relative to ignition timing on the natural-gas direct-injection combustion
Effect of fuel injection timing relative to ignition timing on the natural-gas direct-injection combustion
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DOI：
10.1115/1.1563243
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发表时间：
2003-07-01
影响因子：
1.5
通讯作者：
Kono, M
中科院分区：
文献类型：
--
作者：
Huang, ZH;Shiga, S;Kono, M
利用快速压缩机（RCM）研究了喷油正时相对点火正时对天然气直喷燃烧的影响。点火时间固定在压缩启动后80英寸。当喷射时间较早（喷射开始时间为60ms）时，热释放模式表现为初始阶段燃烧较慢，后期燃烧较快，与预混气体的火焰传播相似。与此相反，当喷射着色较晚时（喷射开始时间为75ms），热释放速率表现为初始阶段燃烧快，后期燃烧慢，与柴油燃烧相似。在较宽的当量比范围内，喷油端正时为80分（与点火正时相同）时，持续时间最短。考虑到燃料喷射产生的装药分层程度和湍流强度是导致这种行为的原因，早期喷射导致初始燃烧持续时间更长，而晚期喷射导致后期燃烧持续时间更长。燃烧产物中CO浓度较低，而NO浓度较低。结果表明，早喷燃烧层化较弱，晚喷燃烧层化较强。在较宽的当量比范围内，燃烧效率保持在较高水平。
The effect of fuel injection timing relative to ignition timing on natural gas direct-injection combustion was studied by using a rapid compression machine (RCM). The ignition timing was fixed at 80 ins after the compression start. When the injection timing was relatively early (injection start at 60 ms), the heat release pattern showed a slower burn in the initial stage and a faster burn in the late stage, which is similar to that of flame propagation of a premixed gas. In contrast to this, when the injection tinting was relatively late (injection start at 75 ms), the heat release rate showed a faster burn in the initial stage and a slower burn in the late stage, which is similar to that of diesel combustion. The shortest duration was realized at the injection end timing of 80 ills (the same timing as the ignition timing) over a wide range of equivalence ratio. The degree of charge stratification and the intensity of turbulence generated by the fuel jet are considered to cause this behavior Early injection leads to longer duration of the initial combustion, whereas late injection leads to a longer duration of the late combustion. Early injection showed relatively lower CO concentration in the combustion products while late injection gave relatively lower NO,. It was suggested that early injection leads to combustion with weaker stratification, and late injection leads to combustion with stronger stratification. Combustion efficiency was kept at a high value over a wide range of equivalence ratio.