Experimental and Analytical Investigation of Hybrid Nanoparticle Enhanced Emulsified Fuel for Performance Optimization in Internal Combustion Engines

Abstract

This research presents an experimental and analytical examination of a hybrid nanoparticle-enhanced water emulsified biodiesel fuel for diesel engine utilization. The suggested fuel is made up of B15 biodiesel (85% diesel and 15% waste cooking oil biodiesel), distilled water, titanium dioxide (TiO₂) nanoparticles (20–30 nm), and carbon quantum dots (CQDs) made from orange peel biomass. The hybrid nano-additives were added to speed up combustion, catalytic oxidation, and secondary atomization through micro-explosion events. We tested a single cylinder, four-stroke, water-cooled, direct-injection diesel engine (3.5 kW, 17.5:1 compression ratio) that ran at a steady speed of 1500 rpm with loads that changed from 25% to 100%, corresponding to experimental points at 25%, 50%, 75%, and 100%. We looked at performance metrics like brake thermal efficiency (BTE) and indicated thermal efficiency (ITE), as well as emissions like NOₓ, HC, CO, and SO₂. The results showed that the maximum BTE was 38.82% at 80% load with 100 mg/L TiO₂, 100 mg/L CQDs, and 5% water content. This is a big improvement over the baseline diesel operation. Adding 10% water cut NOₓ emissions by about 17% because of thermal quenching. Using the best concentrations of nanoparticles cut HC emissions by 78% and CO emissions by 61%. A physics-based artificial neural network (ANN) model was very good at making predictions, with R² values over 0.86 for all output parameters. The hybrid TiO₂–CQD emulsified fuel system had 4–7% higher BTE and 12–18% lower HC emissions than regular single-nanoparticle fuel blends. This shows that the suggested synergistic combustion enhancement approach works.