Establish input parameters for maximizing carbon neutral concoction in CI engine to achieve optimal engine out responses for hybrid operation.

UNLABELLED: The worldwide quest for sustainable energy solutions has intensified interest in improving the efficiency and ecological suitability. This paper examines to maximize use of carbon neutral fuel by strategic function of fuel additives in enhancing combustion properties and facilitating sustainable engine performance. Experiments were conducted to establish mahua biodiesel–diesel blend in the preliminary study. Diethyl ether, a cetane improver is known to minimise ignition delay, improve combustion efficiency, and dramatically reduce hazardous emissions. Further investigation comprises establishing right blend ratio of diethyl ether with optimized mahua biodiesel – diesel blend. The operational requirements for modern engines necessitate a particular ideal condition that can proficiently support various applications, including hybrid powertrains, electrical generators, and irrigation pumps, where reliable performance, fuel efficiency, and regulated emissions are essential. The synergistic effects of the two input factors, namely engine load and fuel concoction, on important performance and emission metrics were systematically investigated using the response surface methodology. The optimised input parameters of 17.15%v/v diethyl ether and 75.43% engine load yielded a significant improvements of 2.03% higher brake thermal efficiency, 22.5% lower carbon monoxide, 26.5% lower hydrocarbon, 25.5% lower smoke, and 6.18% lower nitrogen oxides compared to the neat diesel which was experimentally validated.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-45358-8.