Combustion and emission characteristics of a hydrogen-assisted dual-fuel diesel engine running on garcinia gummi-gutta methyl ester-diesel blends

This research investigates the feasibility of using Garcinia gummi-gutta methyl ester (GGME) blends in conjunction with hydrogen (H 2 ) as an induction gaseous fuel in a dual-fuel diesel engine. GGME was blended with conventional diesel in varying proportions (10 %, 15 %, 20 %, 25 %, and 30 % v/v) to evaluate their performance and emission characteristics. Hydrogen gas, stored in a cylinder, was inducted into the combustion chamber at a fixed injection rate of 5 L/min for all test fuels using an electronic gas injector. The combination of GGME and H 2 gas (5 L/min) demonstrated superior overall performance compared to conventional diesel. Among the various blends tested, GGME_15 + H 2 (5 L/min) exhibited the most promising outcomes. Combustion analysis revealed a heat release rate (HRR) of 70.98 J/°CA and a peak in-cylinder pressure (In-CP) of 79.72 bar at 344°CA for this blend. At maximum engine load, GGME_15 + H 2 (5 L/min) achieved a 5.54 % increase in brake thermal efficiency (BTE) and a 26.67 % reduction in brake specific energy consumption (BSEC) compared to diesel. In terms of emission characteristics, GGME_15 + H 2 (5 L/min) significantly reduced carbon monoxide (CO) by 21.05 %, unburnt hydrocarbons (UBHC) by 13.04 %, and smoke opacity by 25.61 %. However, these benefits came with a 5.12 % increase in nitrogen oxides (NOx) and a 25.64 % rise in carbon dioxide (CO 2 ) emissions compared to diesel. The induction of hydrogen gas with optimally blended GGME-diesel fuels offers a viable alternative to conventional diesel. This approach enhances engine performance, reduces greenhouse gas emissions, and contributes to energy security and sustainability, making it a promising solution for future energy needs. • GGME-diesel blends were tested with H 2 gas induction. • Hydrogen inducted at (5 L/min) using electronic injector. • GGME_15 + H 2 showed best performance and combustion traits. • BTE increased by 5.54 % and BSEC reduced by 26.67 %. • CO, UBHC, and smoke reduced; slight rise in NOx and CO2 observed.