The necessity for energy security and stringent environmental regulations have pushed scientists to investigate new types of fuel and methods to optimize fuel injection settings. Diesel engines fueled by mahua oil biodiesel have their performance and emission characteristics studied in relation to varying injection timings (ITs), exhaust gas recirculation (EGR) and split injection. In the first series of tests, the diesel, B10, and B15 was used with direct injection at 14.2° bTDC. The effects of varying the EGR rate are investigated at optimum fuel injection setting (10.2° bTDC, 24% split injection). Under different loads, the effects of exhaust gas recirculation rates of 8, 16, 24, and 30 % at peak injection circumstances for diesel, B10, and B15 are examined. At maximum throttle, diesel, B10, and B15 all showed lower NOx emissions relative to their baseline values. Diesel and biodiesel blends lowered smoke emissions by 3-3.5% at full load, and carbon monoxide emissions by roughly 55%. © 2024 Elsevier B.V., All rights reserved.