Optimizing CI Engine Performance with Waste Oil Biodiesel, Plastic Pyrolysis Oil, and Diesel Blends Using Python programming

This study investigates the performance, combustion, and emission characteristics of ternary fuel blends composed of diesel, waste cooking oil biodiesel, and pyrolysis oil in a direct injection compression ignition (CI) engine. Experimental tests were conducted using various fuel blends under different injection pressures (180, 210, and 240 bar) and engine loads. Performance metrics such as brake thermal efficiency (BTE), volumetric efficiency, and exhaust gas temperature (EGT) were analyzed, alongside combustion parameters like heat release rate (HRR) and peak in-cylinder pressure. Emissions of NOx, carbon monoxide (CO), smoke opacity, and unburned hydrocarbons (UHC) were also evaluated. The results reveal that an injection pressure of 240 bar optimizes engine performance, improving BTE and volumetric efficiency while reducing fuel consumption for the blends with 70% diesel, 10% pyrolysis oil and 20% sample 2 biodiesel (P10B220D70), 70% diesel, 15% pyrolysis oil and 15% sample 2 biodiesel (P15B215D70), and 70% diesel, 5% pyrolysis oil and 25% sample 2 biodiesel (P5B225D70). Combustion analysis shows that biodiesel-pyrolysis oil blends achieve faster pre-mixed combustion compared to diesel, with peak in-cylinder pressures highest at 240 bar. However, extremely high or low injection pressures negatively affect combustion efficiency. Emission analysis indicates that NOx emissions vary by blend type, with certain blends 70% diesel, 5% pyrolysis oil and 25% sample 1 biodiesel (P5B125D70 and 70% diesel, 5% pyrolysis oil and 25% sample 2 biodiesel (P5B225D70) producing lower values due to reduced premixed combustion. CO emissions decrease with higher injection pressure, while lighter-viscosity blends exhibit reduced smoke opacity. UHC levels remain relatively stable across different loads. Correlation analysis identifies injection pressure as the most influential parameter affecting engine performance and emissions, with blend type and engine load having minimal impact. These findings underscore the potential of biodiesel-pyrolysis oil blends as sustainable alternatives for compression ignition engines when optimized with appropriate injection pressures.