Chemical aspects of the ignition of a primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated by analyzing two-dimensional direct numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found that at the first ignition delay, low-temperature chemistry (LTC) represented by the isomerization of alkylperoxy radical, chain branching reactions of keto-hydroperoxide, and H-atom abstraction of n-heptane is predominant for both RCCI and SCCI combustion. In addition, explosion index and participation index analyses together with conditional means on temperature verify that low-temperature heat release (LTHR) from local mixtures with relatively-high n-heptane concentration occurs more intensively in RCCI combustion than in SCCI combustion, which ultimately advances the overall RCCI combustion and distributes its heat release rate over time. It is also found that at the onset of the main combustion, high-temperature heat release (HTHR) occurs primarily in thin deflagrations where temperature, CO, and OH are found to be the most important species for the combustion. The conversion reaction of CO to CO₂ and hydrogen chemistry are identified as important reactions for HTHR. The overall RCCI/SCCI combustion can be understood by mapping the variation of 2-D RCCI/SCCI combustion in temperature space onto the temporal evolution of 0-D ignition.

通过使用化学炸药分析二维直接数值模拟（DNS）数据，研究了反应性控制压缩点火（RCCI）和分层装料压缩点火（SCCI）条件下主要参考燃料（PRF）/空气混合物着火的化学方面。模式（CEM）分析。通过识别不同位置和时间的控制物质和基本反应，采用CEMA来提供对点火过程的基本见解。发现在第一次点火延迟时，以烷基过氧自由基的异构化，酮状氢过氧化物的链支化反应和n的H原子抽象为代表的低温化学（LTC）庚烷主要用于RCCI和SCCI燃烧。此外，爆炸指数和参与指数分析以及有关温度的有条件手段证明，正构庚烷浓度相对较高的局部混合物产生的低温热释放（LTHR）在RCCI燃烧中的发生比在SCCI燃烧中的发生更为强烈，这最终促进了燃烧的发展。整个RCCI燃烧并随时间分配其放热率。还发现，在主燃烧开始时，高温放热（HTHR）主要发生在稀薄的爆燃中，其中发现温度，CO和OH是最重要的燃烧物质。CO到CO ₂的转化反应氢化学被认为是HTHR的重要反应。通过将温度空间中的2-D RCCI / SCCI燃烧的变化映射到0-D点火的时间演变，可以了解整个RCCI / SCCI燃烧。