摘要：Abstract Stringent emission standards and greater fuel economy have forced scientists to develop an advanced combustion technology (homogeneous charge compression ignition; HCCI) useful in internal combustion engines in the future. Citronella biodiesel prepared through transesterification process which is auspicious an energy source for the CI engine. Cobalt chromium nanoparticles were mixed with the biodiesel at 30 ppm with the help of an ultrasonicator. The present experimental investigation was conducted to analyze various performance (brake thermal efficiency (BTE) and brake‐specific fuel consumption (BSFC)), combustion (pressure and heat release rate (HRR)), and emission (unburnt hydrocarbon (UBHC), CO, NOx, and smoke) parameters of the HCCI engine with neat diesel, CBD 5% (citronella biodiesel 5% + 95% diesel), CBD 10% (citronella biodiesel 10% + 90% diesel), CBD 15% (citronella biodiesel 15% + 85% diesel), CBD 20% (citronella biodiesel 20% + 80% diesel), and CBD 15% + C30 (citronella biodiesel 15% + 85% diesel +30 ppm cobalt). To carry out the experiment, a fuel vaporizer was adopted in a 5.2 kW, 1500 rpm, single‐cylinder, four‐stroke, vertical, direct‐injection diesel engine. Nanoparticles were used to improve surface area/volume ratio, heat conduction, and heat transfer rate within the oil layers. The result showed that CBD 15% had given better results than the other citronella biodiesel‐blended fuels. CBD 15% + C30 fuel increased the BTE and HRR by 5.49% and 6.8%, respectively, due to a shorter ignition delay and greater cetane number of the fuel. The percentage of BSFC, UBHC, CO, NOx, and smoke was decreased by 33.33%, 34.32%, 5.1%, and 17.34%, respectively, compared to neat biodiesel in the HCCI engine at 80% load.
