Prediction and performance optimisation of a DI CI engine fuelled diesel–Bael biodiesel blends with DMC additive using RSM and ANN: Energy and exergy analysis

•Green and sustainable DMC is proposed as an additive to Bael biodiesel for enhancing performance and mitigating emissions.•Bael biodiesel has the potential to achieve 30.68% BTE by B15DMC5, with a worthwhile reduction in emissions.•Process optimization and exergy analysis would support process upcycling and energy conservation.•Provide a way to reduce the carbon footprint by carbon–neutral potential Bael biodiesel.