The main objective of the present study was to investigate combustion instability in a multi-cylinder radial piston engine with electronic fuel injection to ensure safety and reliability, maintain fuel efficiency, reduce harmful emissions, which has a positive impact on the environment. Multi-fractal analysis showed that IMEP (mean effective pressure) fluctuations are an anti-persistent process, meaning that there is no correlation between successive events. The return plots showed significant cyclic variability and instability in neighboring cylinders. The wavelet method and multiscale entropy analysis confirmed the results of the multifractal analysis, showing changes in the characteristics of the combustion process after the introduction of perturbations. The research-based on the first return map has shown an impact on the non-uniform and complex nature of the operation of the neighboring cylinders. The statistical analysis has shown that more than 60 % is slightly negatively skewness in most of the cases, and about 67 % of the cases indicate a leptokurtic distribution of IMEP. Finally, it is concluded that, the combustion of failure of one cylinder in a nine-cylinder engine affects the operation of the other cylinders, as demonstrated through advanced multifractal analysis techniques, return plots, return maps and multiscale entropy analysis.

中文翻译：

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多重分形技术研究电喷多缸径向活塞发动机燃烧不稳定性——比较分析


本研究的主要目的是研究采用电子燃油喷射的多缸径向活塞发动机的燃烧不稳定性，以确保安全性和可靠性，保持燃油效率，减少有害排放，从而对环境产生积极影响。多重分形分析表明，IMEP（平均有效压力）波动是一个反持续过程，即连续事件之间不存在相关性。返回图显示相邻气缸存在显着的循环变化和不稳定性。小波方法和多尺度熵分析证实了多重分形分析的结果，显示了引入扰动后燃烧过程特性的变化。基于第一返回图的研究显示了对相邻气缸操作的不均匀性和复杂性的影响。统计分析表明，大多数情况下超过60%的情况呈轻微负偏态，约67%的情况表明IMEP呈尖峰分布。最后，通过先进的多重分形分析技术、返回图、返回图和多尺度熵分析证明，九缸发动机中一个气缸的燃烧故障会影响其他气缸的运行。