This study investigates the production, optimization, and engine performance of Rubber Seed Oil Methyl Ester (ROME) as a sustainable biodiesel alternative for internal combustion (IC) engines. A two-stage esterification–transesterification process was employed to reduce the free fatty acid content of crude rubber seed oil from ∼ 24% to below 2%, enabling efficient biodiesel synthesis. Ultrasonic-assisted methods were further applied to enhance biodiesel yield. Engine tests demonstrated that pure ROME (B100) produced approximately 5% lower torque and brake horsepower compared to diesel, while showing ∼ 10% higher specific fuel consumption. However, Engine performance analysis revealed that ROME operation resulted in a 4–6% reduction in brake power and torque, along with an increase in specific fuel consumption of 8–12%, primarily due to its lower calorific value. However, brake thermal efficiency improved by approximately 5% under optimized conditions, attributed to enhanced combustion efficiency from the inherent oxygen content of the fuel. Emission analysis indicated a reduction in carbon monoxide (CO) emissions by 15–20%. Energy and exergy analyses revealed maximum engine efficiency at ∼ 80% load capacity. For predictive modeling, Artificial Neural Network (ANN) achieved superior performance (R 2 = 0.974) compared to Response Surface Methodology (RSM). Optimization identified ideal conditions at a compression ratio of 18.849, fuel blend ratio of 11.784%, and supercharged pressure of 1.847 bar, simultaneously maximizing engine efficiency and minimizing emissions. The scientific novelty of this work lies in the combined use of ANN, RSM, and exergy analysis for ROME optimization, offering a robust framework for developing next-generation biodiesels. The findings highlight ROME as a promising renewable fuel candidate with both environmental and energy sustainability benefits.
Murugapoopathi et al. (Fri,) studied this question.