The innovative blend of HVO and biodiesel with diesel for higher generator efficiency, reduction in pollutants and investigation of persistent free radicals emissions

This study evaluates engine performance and emission characteristics of diesel/biodiesel/HVO blends (biodiesel: 0–30% vol., HVO: 10% vol.). Results demonstrate significant reductions: PM2.5 (12.5–43.9%), CO (8.01–24.5%), SO₂ (7.69–25.9%), and NOx (3.33% reduction via HVO addition). Metal emissions (Na/Fe/Ca/Al > 80% of total detected metals) decreased by 24.3–26.8%, while brake-specific fuel consumption (BSFC) improved by 2.21%. Electron paramagnetic resonance (EPR) spectroscopy revealed consistent PM2.5 microstructural properties across blends (g-factor: 2.0033–2.0035), though radical concentrations (3.0 × 1018-7.4 × 1018 spins/g) exceeded ambient levels by 10-fold. Raman analysis confirmed invariant carbon nanostructures (D/G band ratio: 0.910–0.943), indicating fuel composition primarily modulates emission quantity rather than particulate quality. These findings establish HVO-biodiesel blends as effective fossil diesel alternatives, warranting further research on environmentally persistent free radicals (EPFRs).