Abstract One of the alternative fuels considered for powering piston internal combustion engines is ethanol. In some countries, ethanol has been successfully used for many years as a self-contained fuel in positive-ignition engines after relatively minor technical modifications. Due, among other things, to a very low cetane number, this fuel cannot be used in pure form in diesel engines. Consideration is being given to fuels that are blends of diesel fuel with some ethanol fraction. Diesel fuel containing up to 15% (v/v) of ethanol is sometimes referred to as e-diesel or oxygenated diesel. However, it is necessary to improve the autoignition properties of such a blend. Improvement of the autoignition properties of an ethanol–diesel fuel blend (EDB) can be accomplished by introducing an additive that improves the propensity for autoignition. One such additive may be 2-ethylhexyl nitrate (2-EHN), which is commonly used to improve the autoignition properties of diesel fuels. This study determined the effect of the addition of 2-EHN (up to 10,000 ppm [m/m]) on the autoignition properties of an EDB with an ethanol fraction of 15% (v/v). The study was carried out by using a device with a constant volume combustion chamber, which additionally enabled determination of the effect of the ambient gas temperature (in the range 550–650 °C) on the period of ignition delay and the period of combustion delay, as well as the derived cetane number. The average and maximum pressure rise rates in the combustion chamber were also analysed. Studies have shown that, with an increase of the 2-EHN fraction in an EDB, the periods of ignition and combustion delay decrease, and the increase in the temperature of ambient gas into which the fuel is injected shortens these periods to a varying extent.

中文翻译：

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添加硝酸 2-乙基己基十六烷值改进剂对乙醇-柴油混合燃料自燃性能的影响——在不同环境气体温度下的研究

摘要 为活塞式内燃机提供动力的一种替代燃料是乙醇。在一些国家，乙醇在经过相对较小的技术改造后，已成功用作正燃发动机的独立燃料多年。除其他外，由于十六烷值非常低，这种燃料不能以纯形式用于柴油发动机。正在考虑将柴油与一些乙醇馏分混合的燃料。乙醇含量高达 15% (v/v) 的柴油燃料有时被称为电子柴油或氧化柴油。然而，有必要改进这种混合物的自燃性能。乙醇-柴油燃料混合物 (EDB) 的自燃性能的改进可以通过引入一种提高自燃倾向的添加剂来实现。一种这样的添加剂可以是硝酸 2-乙基己酯 (2-EHN)，它通常用于改善柴油燃料的自燃性能。本研究确定了添加 2-EHN（高达 10,000 ppm [m/m]）对乙醇分数为 15% (v/v) 的 EDB 自燃特性的影响。该研究是通过使用具有恒定体积燃烧室的装置进行的，该装置另外能够确定环境气体温度（在 550-650 °C 范围内）对点火延迟时间和燃烧延迟时间的影响，以及导出的十六烷值。还分析了燃烧室中的平均和最大压力上升率。研究表明，随着 EDB 中 2-EHN 分数的增加，点火时间和燃烧延迟时间减少，