Tefera Negasa Tesfaye, Nallamothu Ramesh Babu, Alemayehu Getachew
Department of Mechanical Engineering, College of Mechanical Chemical and Materials Engineering, Adama Science and Technology University, Adama, Ethiopia.
Sci Rep. 2025 Jul 18;15(1):26023. doi: 10.1038/s41598-025-97620-0.
The rising demand for energy and environmental challenges posed by fossil fuel reliance necessitate innovative solutions in internal combustion engines. RCCI combustion has emerged as a promising strategy to address these issues by utilizing dual fuels with distinct reactivities to achieve efficient and cleaner engine operation. This study examines the performance metrics, combustion, and emission profiles of an RCCI engine, leveraging the synergistic effects of renewable and oxygenated fuels; n-butanol and gasoline as the LRF, alongside a biodiesel blend (B20) as the HRF. The experiments were conducted on a modified single-cylinder CI engine specifically adapted for RCCI operation, where the LRF was introduced through port injection and the HRF was injected directly. The experiments were conducted at a maximum load of 80%, varying speeds, and different fuel blend ratios. The port-injected fuel mixture was composed of varying volume fractions: 5% gasoline and 15% n-butanol (G25n-b75), 10% gasoline and 10% n-butanol (G50E50) and 15% gasoline and 5% n-butanol (G75n-b25). The mixtures were blended and made up 20% of the total fuel, while the remaining 80% was the biodiesel-diesel blend (B20) used in direct injection for RCCI engine mode investigation. The findings indicate that the B20+G50n-b50 configuration achieved the highest cylinder pressure of 92.25 bar, significantly exceeding the baseline fuel's 57.24 bar at 2800 rpm. Among tested configurations, B20+G50n-b50 demonstrated the optimal performance, achieving the highest brake power (4.35 kW). The lowest NOx (150 ppm) and CO (3.7 vol%) emissions were achieved with engine operated B20+G25n-b75 configurations at 2800 rpm. The CO and HC emissions rise with B20+G25n-b75 and B20+G50n-b50, whereas B20+G75n-b25 achieves the lowest emissions. This can be considered a novel finding, demonstrating CO and HC emissions reduction through RCCI in this study. The study highlights the capability of RCCI engines to attain exceptionally low emissions levels when utilizing renewable fuel blends. These findings provide important insights into fuel optimization and emission reduction methods for RCCI applications, advancing cleaner and more sustainable engine technologies.
对能源的需求不断增加以及依赖化石燃料所带来的环境挑战，使得内燃机需要创新解决方案。反应控制压缩点火（RCCI）燃烧作为一种有前景的策略应运而生，它通过使用具有不同反应活性的双燃料来实现发动机高效且更清洁的运行，以应对这些问题。本研究考察了一台RCCI发动机的性能指标、燃烧情况和排放特征，利用可再生燃料和含氧燃料的协同效应；以正丁醇和汽油作为低反应活性燃料（LRF），同时使用生物柴油混合燃料（B20）作为高反应活性燃料（HRF）。实验在一台经过改装的单缸压燃式发动机上进行，该发动机专门适配RCCI运行，其中低反应活性燃料通过进气道喷射引入，高反应活性燃料则直接喷射。实验在最大负荷80%、不同转速和不同燃料混合比的条件下进行。进气道喷射的燃料混合物由不同体积分数组成：5%汽油和15%正丁醇（G25n - b75）、10%汽油和10%正丁醇（G50n - b50）以及15%汽油和5%正丁醇（G75n - b25）。这些混合物混合后占总燃料的20%，而其余80%是用于RCCI发动机模式研究的直接喷射的生物柴油 - 柴油混合燃料（B20）。研究结果表明，在2800转/分钟时，B20 + G50n - b50配置实现了最高气缸压力92.25巴，显著超过基准燃料的57.24巴。在测试的配置中，B20 + G50n - b50表现出最佳性能，实现了最高制动功率（4.35千瓦）。在28,00转/分钟时，采用B20 + G25n - b75配置运行的发动机实现了最低的氮氧化物（150 ppm）和一氧化碳（3.7体积%）排放。采用B20 + G25n - b75和B20 + G50n - b50配置时，一氧化碳和碳氢化合物排放增加，而B20 + G75n - b25实现了最低排放。这可被视为一项新发现，表明本研究中通过RCCI实现了一氧化碳和碳氢化合物排放的降低。该研究突出了RCCI发动机在使用可再生燃料混合物时实现极低排放水平的能力。这些发现为RCCI应用中的燃料优化和减排方法提供了重要见解，推动了更清洁、更可持续的发动机技术发展。
