Impact of Multiferrite Nanoparticles on Combustion Characteristics of <i>Terminalia bellirica</i> Biodiesel in Compression Ignition Engines

ABSTRACT The present work investigates the effects of zinc and manganese co‐doped bismuth ferrite nanoparticles (BZnFMO) on the combustion behavior of a diesel engine running on a 20% blend of Terminalia bellirica biodiesel (B20). To overcome the challenges associated with biodiesel combustion efficiency and dispersion uniformity, BZnFMO nanoparticles were incorporated at concentrations of 50 ppm and 75 ppm. CTAB was used as a surfactant and TWEEN 80 as a dispersant to promote a stable and homogeneous distribution of the nanoparticles in the fuel matrix. The stability of the nanoparticle dispersion was evaluated by UV‐visible spectral analysis over a period of 3 weeks, with the formulation containing 75 ppm BZnFMO and 75 ppm TWEEN 80 showing higher stability. The combustion characteristics of these nanofuels were experimentally evaluated in a single‐cylinder diesel engine at three injection timings: 21°, 23°, and 25° bTDC. The addition of BZnFMO nanoparticles optimized combustion performance by increasing cylinder pressure (CP), net heat release rate (NHRR) and mean gas temperature (MGT), driven by superior catalytic activity and refined fuel atomization. At an advanced injection timing of 25°bTDC, the B20 fuel formulation containing 75 ppm BZnFMO and 75 ppm TWEEN 80 achieved superior combustion metrics, including a maximal CP (71.14 bar), highest NHRR (56.18 J/°CA), and peak MGT (1645.66°C). This study presents an innovative strategy that combines surface‐modified, encoded nanoparticles with optimized injection timing to significantly improve the combustion of biodiesel in engines. This represents a significant advance over previous studies on biodiesel‐based nanofuels.