Experimental Investigations on Dual-Fuel Engine Fueled with Tertiary Renewable Fuel Combinations of Biodiesel and Producer—Hydrogen Gas Using Response Surface Methodology

Abstract

The effects of producer gas (PG), hydrogen (H2), and neem oil methyl ester-blended fuel (NeOME B20) flow rate optimization on dual fuel (DF) engine performance were examined in the current work. PG and H2 were used as primary fuels, while NeOME B20 was used as a secondary pilot fuel in the DF engine. The DF engine’s performance and pollution levels were optimized using response surface methodology (RSM) and the results were compared with experimental values. The full factorial design (FFD) has been used to minimize the number of experiments. The design of experiments (DOEs) with an experimental design matrix of 27 distinct combinations were taken into consideration. The primary goal of the effort is to optimize different fuel flow rates for better brake thermal efficiency (BTE) and lower tail pipe exhaust pollutants. The developed RSM model is validated with experimental results for the selected fuel flow rates using a desirability approach. Experiments were carried out at a constant speed of 1500 rpm, compression ratio (CR) of 17.5, injector opening pressure (IOP) 240 bar, six-hole nozzle with 0.2 mm diameter, and injection timing (IT) of 27° before top dead center (bTDC). The flow rates of NeOME B20, PG, and H2 varied from 0.4 to 0.8 kg/h, 7 to 9 kg/h, and 0.029 to 0.059 kg/h, respectively. Optimum flow rates for NeOME B20, PG, and H2 were found to be 0.8, 7, and 0.044, kg/h respectively for the maximized break thermal efficiency (BTE) and reduced exhaust emission levels. However, a marginal increase in NOx was noticed. In addition, the delay period and combustion duration were reduced, and the cylinder pressure (CP) and heat release rate (HRR) were increased for the optimal condition with a desirability of 0.998. Overall, DF operation with selected fuel combinations was found to be smooth and satisfactory.