Two-stage ignition in HCCI combustion and HCCI control by fuels and additives
Two-stage ignition in HCCI combustion and HCCI control by fuels and additives
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DOI：
10.1016/s0010-2180(02)00457-1
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发表时间：
2003-01-01
影响因子：
4.4
通讯作者：
Heywood, JB
中科院分区：
文献类型：
--
作者：
Tanaka, S;Ayala, F;Heywood, JB
利用快速压缩机（RCM）研究了燃料结构和添加剂对纯烃燃料和混合燃料均质压缩点火（HCCI）的影响。这些信息对于理解HCCI发动机的点火延迟和燃烧速率以及火花点火发动机的“爆震”是必需的。这对验证烃类氧化的基本化学动力学模型也有价值。研究中使用的纯燃料包括：石蜡（正庚烷、异辛烷）、环石蜡（环己烷、甲基环己烷）、烯烃（1-庚烯、2-庚烯、3-庚烯）、环烯烃（环己烯、1,3-环己二烯）和芳香烃（甲苯）。添加剂为硝酸2-乙基己基和过氧化二叔丁基。结果表明，含有- ch2 - ch2 - ch2 -结构的燃料表现为两段点火，其点火延迟时间较短，且点火延迟时间主要取决于第一段释放的能量。对于主要参考燃料混合物（正庚烷+异辛烷），点火延迟仅取决于正庚烷与氧的摩尔比，而与辛烷值（异辛烷百分比）无关。另一方面，燃烧速率取决于这两个参数，这两个参数唯一地决定了等效比。当在空气/燃料混合物中加入添加剂时，点火延迟降低，但燃烧速率不受影响。这些结果表明，对于HCCI燃烧，不同的燃料混合物和添加剂可以独立控制点火延迟和燃烧速率。(C) 2003燃烧研究所。版权所有。
A Rapid Compression Machine (RCM) has been used to study the effects of fuel structure and additives on the Homogeneous Charge Compression Ignition (HCCI) of pure hydrocarbon fuels and mixtures under well-determined conditions. Such information is needed for understanding ignition delays and burning rates in HCCI engines, and "knock" in spark-ignition engines. It is also valuable for validating basic chemical kinetic models of hydrocarbon oxidation. The pure fuels used in the study include: paraffins (n-heptane, iso-octane), cyclic paraffins (cyclohexane, methylcyclohexane), olefins (1-heptene, 2-heptene, 3-heptene), cyclic olefins (cyclohexene, 1,3-cyclohexadiene), and an aromatic hydrocarbon (toluene). The additives were 2-ethyl-hexyl-nitrate and di-tertiary-butyl-peroxide. It was found that fuels which contained the structure -CH2-CH2-CH2- showed two-stage ignition with relatively short ignition delays and that the ignition delay depended strongly on the energy released during the first-stage. For primary reference fuel mixtures (n-heptane + iso-octane), the ignition delay depended only on the molar ratio of n-heptane to oxygen and was independent of the octane number (percent iso-octane). On the other hand, the burn rate depended on both these parameters, which uniquely determine the equivalence ratio. When additives were included in the air/fuel mixtures, the ignition delay was reduced but the burn rate was not affected. These results indicate that for HCCI combustion, the ignition delay and the burn rate can be independently controlled using various fuel mixtures and additives. (C) 2003 The Combustion Institute. All rights reserved.