Guo Zhefeng, Hsieh Yu-Lun, Lin Sheng-Lun, Lee Yen-Yi, Lee Timothy H
College of Energy Engineering, Zhejiang University, Hangzhou 310027, PR China.
ZJU-UIUC Institute, Zhejiang University, Haining 314400, PR China.
ACS Omega. 2024 Dec 6;9(50):49966-49979. doi: 10.1021/acsomega.4c09313. eCollection 2024 Dec 17.
Nano-AlO derived from recyclable sources emerges as a promising sustainable solution for enhancing diesel engine efficiency while mitigating emissions. However, a lack of an in-depth understanding of the health hazard aspect still challenges its commercial applications. To this end, nano-AlO/diesel (NAD) blends prepared via ultrasonic homogenization were experimentally and analytically investigated under various injection timings and excess air coefficients to explore the potential of nano-AlO for balancing energy performance and emissions. Results revealed a synergistic effect between the NAD blends and optimized combustion control strategies. NAD blends presented enhanced heat release and pressure rise rates even under late injection or hypoxic conditions, indicating a faster and more complete combustion. Specifically, NAD blends promoted the partially premixed combustion phase and reduced postcombustion duration. While a slight increase in fuel consumption and a decrease in thermal efficiency were observed, potentially due to minor chamber compatibility issues, a significant improvement in emissions was identified. NAD blends effectively mitigated the well-known soot-particulate number-nitrogen oxide (NOx) trade-off inherent in diesel engines. NAD blends achieved lower NOx emissions through the even temperature distribution promoted by nano-AlO, minimizing the formation of NOx precursors. Simultaneously, NAD blends contributed to a reduction in soot emissions as well as an increment in nucleation mode particles, which are smaller and more harmful than conventional engine-out particulates. Notably, deposition modes highlighted that a higher nano-AlO addition leads to an increase in nucleation mode particles, resulting in a higher alveolar deposition ( = 5-100 nm) and lower nasal deposition ( = 200-800 nm). These findings suggest that, by optimizing injection timing and excess air coefficients, NAD blends offer a promising approach to enhance combustion and achieve cleaner emissions simultaneously, making them a valuable contribution to the development of more sustainable diesel engine technologies.
源自可回收资源的纳米氧化铝成为一种有前景的可持续解决方案，可提高柴油发动机效率并减少排放。然而，对健康危害方面缺乏深入了解仍然制约着其商业应用。为此，通过超声均质化制备的纳米氧化铝/柴油（NAD）混合燃料在不同喷射正时和过量空气系数下进行了实验和分析研究，以探索纳米氧化铝在平衡能量性能和排放方面的潜力。结果显示了NAD混合燃料与优化燃烧控制策略之间的协同效应。即使在晚喷射或缺氧条件下，NAD混合燃料也表现出增强的热释放和压力上升速率，表明燃烧更快且更完全。具体而言，NAD混合燃料促进了部分预混燃烧阶段并缩短了后燃持续时间。虽然观察到燃料消耗略有增加且热效率有所降低，这可能是由于轻微的燃烧室兼容性问题，但排放有显著改善。NAD混合燃料有效缓解了柴油发动机中众所周知的烟灰 - 颗粒数量 - 氮氧化物（NOx）权衡问题。NAD混合燃料通过纳米氧化铝促进的均匀温度分布实现了更低的NOx排放，最大限度地减少了NOx前驱体的形成。同时，NAD混合燃料有助于减少烟灰排放以及增加成核模式颗粒，这些颗粒比传统的发动机尾气颗粒更小且更有害。值得注意的是，沉积模式表明，更高的纳米氧化铝添加量会导致成核模式颗粒增加，从而导致更高的肺泡沉积（粒径 = 5 - 100纳米）和更低的鼻腔沉积（粒径 = 200 - 800纳米）。这些发现表明，通过优化喷射正时和过量空气系数，NAD混合燃料为增强燃烧并同时实现更清洁排放提供了一种有前景的方法，使其对更可持续的柴油发动机技术发展做出了宝贵贡献。
