Abstract In this research work, cycle-by-cycle variations of a single cylinder, diesel engine operated with raw biogas is investigated. The biogas used to run the engine is obtained from food waste and as the composition of 88.10%-CH4 + 11.895%-CO2. To study the combustion characteristics, the naturally aspirated diesel engine is converted into dual mode by inducting the biogas into the intake manifold for different proportions from BG20 to BG60 with a step of 10% is mixed with air (i.e. BG60-60% of biogas by mass) respectively. Combustion parameters are measured and recorded by the means of the data acquisition system (DAQ) for 100 combustion cycle. By determining the parameters such as standard deviation, coefficient of variation and return map, the cycle variability is analyzed. From the experimental result, it is observed that as the engine is operated at higher loads and as the biogas is increased from BG20 to BG60 the cyclic variations for maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) increases. Coefficient of variation of Pmax for BG20 and BG40 is lower by 2.3% and 11.98% as compared to diesel. From time return map, BG40 showed good combustion stability and lesser NOx emission compared to diesel.

中文翻译：

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双工况下以原沼气为燃料的单缸柴油机循环变化的实验研究

摘要 在这项研究工作中，研究了使用原始沼气运行的单缸柴油发动机的循环变化。用于运行发动机的沼气来自食物垃圾，其成分为 88.10%-CH4 + 11.895%-CO2。为研究燃烧特性，将自然吸气柴油机以BG20 至BG60 的不同比例以10% 的比例与空气混合（即BG60-60% 的沼气通过质量）分别。通过数据采集系统（DAQ）对 100 个燃烧循环的燃烧参数进行测量和记录。通过确定标准偏差、变异系数和返回图等参数，分析循环变异性。从实验结果来看，据观察，当发动机在更高的负载下运行并且沼气从 BG20 增加到 BG60 时，最大气缸压力 (Pmax) 和指示平均有效压力 (IMEP) 的循环变化增加。BG20 和 BG40 的 Pmax 变异系数比柴油低 2.3% 和 11.98%。从时间返回图来看，与柴油相比，BG40 显示出良好的燃烧稳定性和更少的 NOx 排放。