Ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and sec-butanol are six potential carbon-neutral fuels of the future. One application of these carbon-neutral fuels is in high-dilution spark ignition. To understand the potential of these fuels in high-dilution spark ignition, this work experimentally determines the spark ignition lean flammability limit of each fuel with no external, cooled exhaust gas recirculation (EGR), and with 20% external, EGR. The spark ignition lean flammability limit in this work is defined as the excess-air ratio that results in a coefficient of variance of gross indicated mean effective pressure greater than 5%. This is done on an engine with a compression ratio of 12.5, using an intake pressure of 1 bar and an intake temperature of 320 K. It was found that ethanol had the leanest lean limit, due to its high flame speed, followed by n-propanol, isopropanol, and sec-butanol, which all had similar lean limits. n-Butanol and isobutanol had the richest lean limits due their high knock propensity and low flame speed, respectively. The lean limit of each fuel decreased with external, cooled EGR addition, with ethanol as the least sensitive and isopropanol as the most sensitive to EGR addition. Overall, using a high dilution strategy increased the cycle efficiency for each fuel. Ethanol, n-propanol, isopropanol, and sec-butanol all showed promising performance and are great candidates to be combined with an advanced high-dilution SI strategy to enable high-dilution SI with a carbon-neutral fuel.

乙醇，正丙醇，异丙醇，n-丁醇，异丁醇和仲丁醇是未来六种潜在的碳中和燃料。这些碳中性燃料的一种应用是高稀释度火花点火。为了了解这些燃料在高稀释火花点火中的潜力，这项工作通过实验确定了在没有外部冷却废气再循环（EGR）且外部EGR为20％的情况下每种燃料的火花点火贫油可燃极限。这项工作中的火花点火稀燃性极限定义为过量空气比率，该比率导致总指示平均有效压力的变异系数大于5％。这是在压缩比为12.5的发动机上，使用1 bar的进气压力和320 K的进气温度下完成的。发现乙醇具有最稀薄的极限，这是由于其较高的火焰速度，其次是正丙醇，异丙醇和仲丁醇均具有相似的贫油极限。正丁醇和异丁醇分别由于其较高的爆震倾向和较低的火焰速度而具有最丰富的稀薄极限。每种燃料的稀薄极限随外部冷却的EGR添加而降低，乙醇对EGR添加的敏感性最低，而异丙醇对EGR的敏感性最高。总体而言，采用高稀释策略可提高每种燃料的循环效率。乙醇，正丙醇，异丙醇和仲丁醇均显示出令人鼓舞的性能，并且是与先进的高稀释SI策略结合使用的理想选择，以实现碳中和燃料的高稀释SI。