A novel investigation on hydrogen induction and compression ratio on atomization and performance combustion emissions of heated biodiesel blends in diesel engines

Abstract This study investigates the influence of hydrogen in dual‐fuel operation with waste cooking oil based biodiesel blend (B20) and diesel on atomization behavior across varying injection pressures (200–1000 bar). The engine testing was performed employing diesel, unheated, and preheated biodiesel‐blends (65°C) on various compression ratios (16.5, 17.5: SCR, 18.5, 19.5). Thereafter, hydrogen was utilized as an auxiliary fuel at controlled flow rates of 3, 5, 7, 9, 12, and 15 lpm. Some key findings were highlighted: (i) Biodiesel exhibited larger sauter mean diameter (SMD) than diesel at all injection pressures and B20@12%H2 exhibited 12.31% larger SMD than D@12%H2 (ii) At the flow rate of 15 lpm and CR of 17.5, preheated CR_17.5 showed 6.09% higher brake thermal efficiency than unheated B20_SCR fuel, while brake specific fuel consumption was decreased by 8.62% for unheated B20_SCR. (iii) At standard compression ratio (SCR), the emissions of CO, HC and smoke were reduced by 56.12%, 30.11%, and 29.74%, respectively, compared to Diesel_SCR. While, NOx was increased by 13.43% as compared to diesel fuel at SCR.