Investigation on cycle variability characteristics of lean-burn in an aviation kerosene piston engine

This paper takes a small-scale aviation kerosene piston engine as the research subject and conducts whole-engine operation tests under different equivalence ratios, effective compression ratios and ignition timings. The parameters such as power, fuel consumption rate, and cycle variability of the aviation kerosene piston engine under different conditions were obtained. The results indicate that when the effective compression ratio is 9.1, the equivalence ratio is 0.91, and the ignition timing is between -26°CA and -18°CA, the engine achieves a lower fuel consumption rate under cruising conditions. Advancing the ignition timing exacerbates cycle variability, and reducing the equivalence ratio (lowering the mixture concentration) increases cycle variability. The phase space reconstruction method was employed to deeply investigate the dynamic characteristics of cycle variations. The results demonstrate that using a differential coordinate system to project the one-dimensional cylinder pressure-time series onto the X-Y plane effectively unfolds the development of multi-cycle cylinder combustion processes with crankshaft angle variations. When the equivalence ratio decreases to 0.83, the region where the trajectory diverges most conspicuously moves further from the ignition point. The divergence of the trajectory is greatest at the maximum X value, indicating incomplete combustion and increased cycle variability.