Liquefied petroleum gas (LPG) is a low-carbon fuel with an existing fuel supply infrastructure. As compared to petroleum-based gasoline, it features a higher octane rating. As compared to port fuel injection (PFI) systems, the direct injection (DI) of LPG engines reveals significant advantages in modern spark-ignition, such as higher efficiency. LPG primarily consists of C₃ and C₄ hydrocarbons, but the composition can drastically vary according to the current European LPG fuel standard EN 589. Several studies have focused already on understanding the oxidation process of its primary components. In this study, the focus will be on the autoignition behavior of different LPG compositions. Thereto, four different LPG fuels according to the current European LPG fuel standard EN 589 have been investigated. They cover a wide range of compositions and thus different autoignition behaviors. The fuels involve an LPG with a maximum propene/propane content, a typical winter-grade LPG with propane/n-butane/isobutane content, a high propane content, and high n-butane/isobutane content. These fuels also contain minor fragments of C₂ and other C₄ hydrocarbons. A rapid compression machine (RCM) has been used in this study to measure ignition delay times primarily in the low-to-intermediate temperature regime at stoichiometric conditions with a final compression pressure of 20 bar. Zero-dimensional simulations, including the facility effects of the RCM, have been performed with the help of detailed chemical kinetic mechanisms reported in the literature. The Aramco Mech 3.0 mechanism was chosen on the basis of its ability to represent the experimental data investigated in this study and additionally on the basis of the criteria that the major species in the mechanism are available and validated at application-relevant conditions. The mechanism is further used to understand the oxidation behavior of the fuel. Sensitivity analyses with the selected mechanism at application-relevant conditions were performed for the different LPG mixtures to reveal the most sensitive reactions, which affect the reactivity of the fuel. Similarly, to monitor the rate of production and consumption of species at experimental conditions of interest, flux analyses were performed at the point where 20% of the fuel is consumed. From the performed kinetic analyses, it is observed that the production of HȮ₂ radicals by the subchemistry of the primary fuel component is consumed by propene subchemistry, leading to more ȮH radical production, which controls the global reactivity in the investigated regime.

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了解汽车液化石油气燃料的氧化行为：实验和动力学分析

液化石油气（LPG）是具有现有燃料供应基础设施的低碳燃料。与石油基汽油相比，它具有更高的辛烷值。与港口燃料喷射（PFI）系统相比，液化石油气发动机的直接喷射（DI）具有现代火花点火的显着优势，例如效率更高。液化石油气主要由C ₃和C _4组成碳氢化合物，但其组成可能会根据当前的欧洲LPG燃料标准EN 589发生巨大变化。一些研究已经集中在理解其主要成分的氧化过程上。在这项研究中，重点将放在不同LPG成分的自燃行为上。迄今为止，已经研究了根据当前欧洲LPG燃料标准EN 589的四种不同LPG燃料。它们涵盖了广泛的成分，因此具有不同的自燃行为。燃料涉及具有最大丙烯/丙烷含量的LPG，具有丙烷/正丁烷/异丁烷含量，高丙烷含量和高正丁烷/异丁烷含量的典型冬季等级LPG 。这些燃料还含有少量的C ₂和其他C碎片₄碳氢化合物。快速压缩机（RCM）已用于本研究中，主要在化学计量比条件下，最终压缩压力为20 bar的中低温度范围内测量点火延迟时间。零维模拟，包括RCM的设施效应，已经在文献中报道的详细化学动力学机制的帮助下进行了。选择Aramco Mech 3.0机理的依据是其能够代表本研究中研究的实验数据的能力，此外还基于该机理中主要物种均可用并在与应用相关的条件下得到验证的标准。该机制还用于了解燃料的氧化行为。在与应用程序相关的条件下，使用选定的机制对不同的LPG混合物进行了敏感性分析，以揭示最敏感的反应，这会影响燃料的反应性。同样，为了监控感兴趣的实验条件下物种的生产和消耗速率，在消耗20％燃料的时间点进行了通量分析。从进行的动力学分析可以看出，H 3的产生主要燃料组分的亚化学中的_2个自由基被丙烯亚化学消耗，从而导致更多的ȮH自由基产生，这在所研究的体系中控制了整体反应性。