Cycle-to-Cycle Variation in Diesel Engines Using Water-Diesel-Butanol Blended Fuels

Abstract

This study investigates the cycle-to-cycle variations in cylinder pressure. It indicates the mean adequate pressure (IMEP) of a single-cylinder diesel engine fueled with water-in-diesel-butanol (WDBu) emulsified blends at various engine loads. Experiments were conducted at a constant engine speed of 3,000 rpm under 50% load, using five different fuel types: pure diesel (D), water-in-diesel (W5D), and three WDBu blends W5DBu5, W5DBu10, and W5DBu15. Results revealed that the highest peak cylinder pressure (Pmax) of 89.10 bar was recorded with W5DBu10, while the lowest (79.03 bar) was observed with W5DBu15. The maximum pressure variation was most stable for W5D with a %RSD of 1.23% and least stable for W5DBu10 with a %RSD of 2.21%. Notably, the W5DBu5 blend showed a moderate Pmax variability of 8.95 bar and produced the most inconsistent pressure across 100 cycles. Regarding IMEP cyclic variation, the coefficient of variation (COVimep) was used to assess combustion stability at engine loads of 20%, 35%, and 50%. At 50% load, W5DBu5 exhibited the lowest COVimep of 1.10, indicating superior cyclic stability compared to diesel, which showed the highest COVimep of 1.26. The findings suggest that a WDBu5 blend offers an optimal balance between performance and stability, positioning it as a promising alternative fuel for compression ignition engines. This study contributes valuable insights for enhancing combustion consistency in alternative fuel applications.