Examining the effects of varying diesel, biodiesel, and ethanol fuel ratios on engine efficiency and emissions

The objective of this work is to examine the emissions and combustion properties of diesel engines when different diesel-methanol mixtures are considered. The parameters included under this category consist of cylinder pressure, heat release rate, cylinder temperature, and nitrogen oxides and carbon monoxide emissions. The aim of this work was to determine the impact of various combinations on automotive diesel engines. Experimental validation was conducted to assess the precision of the simulation model for B5, a commercially available diesel mix containing 5% biodiesel; B5E10, which contains 10% ethanol in B5; B5E10, which contains 15% ethanol in B5; and B5E20, which contains 20% ethanol in B5. As ethanol fraction grows in diesel–biodiesel–ethanol blends, simulation results at 50%, 75%, and 100% engine loads show combustion and emission patterns. Peak cylinder pressure rose by 0.75%, 1.01%, and 1.21% for B5E10, B5E15, and B5E20 compared to pure diesel at full load, showing better premixed combustion due to fuel–air mixing. Due to ignition delay and oxygenation, ethanol-enriched mixes had greater peak heat release rates. Due to ethanol's decreased calorific value, high-ethanol mixes’ maximum cylinder temperature dropped 4–6%. NOx emissions increased proportionately with load and ethanol fraction, whereas CO emissions declined steadily as ethanol % climbed, indicating more thorough oxidation under oxygen-rich combustion. The numerical results show that modest ethanol replacement increases combustion intensity and decreases incomplete-combustion emissions with a small NOx penalty.