Evaluating the combustion characteristics of Prosopis Juliflora biodiesel with diethyl ether additives in diesel engines

Fossil fuels contribute heavily to global greenhouse gas emissions and their fast depletion necessitates sustainable alternatives. Biodiesel produced from non-edible oils like those of invasive plant species can provide renewable options without concerns of food security or land-use changes. This study experimentally investigates the combustion characteristics of biodiesel derived from Prosopis Juliflora (PJ), an invasive shrub in Ethiopia, when blended with diesel and diethyl ether (DEE) additive. The primary objective is to optimize the combustion of PJ biodiesel in a diesel engine by identifying the optimal DEE concentration and analyzing its impact on combustion parameters. Biodiesel was produced from PJ seeds through transesterification and blended in a 20 % ratio with diesel fuel. DEE was added to this mixture in varying concentrations (5 %, 10 %, 15 %, and 20 %). The combustion characteristics, including cylinder pressure and heat release rate (HRR), were evaluated on a single-cylinder diesel engine at a constant speed of 2600 rpm under different engine loads. The results demonstrate that a 10 % DEE blend yields the most significant improvement, with a 6.5 % increase in peak cylinder pressure and a 4.7 % rise in heat release rate, compared to baseline diesel. Furthermore, engine brake power output showed maximum enhancement at this DEE concentration. The improved combustion is attributed to the synergistic effects of PJ biodiesel's high cetane number and DEE's low viscosity and high volatility, which reduce ignition delay and enhance fuel atomization. This study provides the first comprehensive investigation into the combustion optimization of PJ biodiesel with DEE additives, demonstrating its potential as a sustainable, renewable alternative to petrodiesel without requiring engine modifications. Such non-edible biodiesel-ether blends provide feasible renewable substitutes to petrodiesel.