In this study, spark assisted compression ignition (SACI) combustion was investigated using PRF95 (a low reactivity high octane reference fuel of common commercial gasoline), a mixture of 95% isooctane (by volume) and 5% n-heptane (by volume) with a RON of 95 and compared with pure compression-ignition without spark. Characteristics like the cumulative heat release (CHR) and the heat release rates (HRR) were studied using pressure data from experiments conducted in a constant volume combustion chamber (CVCC). The combustion process was visualized with a high speed imaging technique. Tests were conducted to understand the effects of ambient oxygen concentration and temperatures on the heat release and combustion flame developments while controlling other factors. From the experiments it is evident that the peak heat release rate increases initially and then decreases with the increase in the ambient temperature and the highest peak heat release rate appears around 650–700 K. The peak heat release rate timing decreases with the increase of the ambient temperature or oxygen level. Under a low ambient temperature, the oxygen level plays a major role in affecting the peak heat release rate. Under lower oxygen levels, the flame becomes weaker, the ignition delay becomes longer, and the combustion process takes more time to complete. Proper spark timing can help advance the peak HRR and shorten ignition delay, but this effect becomes minor when the ambient temperature increases. For the current high octane low reactivity fuel, auto-ignition can be achieved for all the investigated ambient temperature and oxygen levels. But it is noticed that a spark is necessary for low ambient oxygen and low ambient temperature to achieve proper combustion.

在这项研究中，使用 PRF95（一种普通商业汽油的低反应性高辛烷值参考燃料）、95% 异辛烷（按体积计）和 5% 正庚烷（按体积计）的混合物研究了火花辅助压缩点火 (SACI) 燃烧RON 为 95，与无火花的纯压缩点火相比。使用来自在恒容燃烧室 (CVCC) 中进行的实验的压力数据研究了累积放热 (CHR) 和放热率 (HRR) 等特性。燃烧过程是用高速成像技术可视化的。进行测试以了解环境氧气浓度和温度对放热和燃烧火焰发展的影响，同时控制其他因素。从实验中可以看出，随着环境温度的升高，峰值放热率先升高后降低，最高放热率峰值出现在 650-700 K 附近。峰值放热率时间随着环境温度的增加而降低。环境温度或氧气水平。在低环境温度下，氧含量在影响峰值放热率方面起主要作用。在较低的氧气含量下，火焰变弱，点火延迟变长，燃烧过程需要更多时间才能完成。正确的点火正时有助于提高峰值 HRR 并缩短点火延迟，但当环境温度升高时，这种影响会变得很小。对于目前的高辛烷值低反应性燃料，可以在所有调查的环境温度和氧气水平下实现自燃。但需要注意的是，低环境氧和低环境温度需要火花才能实现适当的燃烧。