Experimental investigation on performance, emission and combustion analysis of common rail direct injection (CRDI) engine fuelled with momordica charantia biodiesel

• The current research investigation uses Momordica Charantia (MC) biodiesel in a CRDI engine. An experiment was conducted to assess the performance, combustion, and emission characteristics of a single-cylinder, four-stroke, direct-injection, 5.95 kW diesel engine running on biodiesel and diesel-biodiesel blends. • The engine's combustion properties were evaluated, including in-cylinder pressure, heat release, ignition delay, and brake thermal efficiency. • Test fuels were also assessed for unburned hydrocarbon, carbon monoxide, nitrogen oxide, and smoke emissions. • Biodiesel blends and control diesel fuel were compared in an experimental study. As a result of the test findings, B20 blend can be used in diesel engines without requiring any modification to achieve satisfactory thermal efficiency and improved exhaust emissions. The growing demand for renewable and sustainable fuels has led to increased interest in non-edible biodiesel feedstocks for compression ignition (CI) engines. In this study, Momordica charantia (MC) biodiesel was blended with diesel at various proportions (B10, B20, B30) and tested in a single-cylinder, four-stroke, CRDI diesel engine (5.95 kW). The investigation focused on performance, combustion, and emission characteristics under different operating conditions. Results indicated that brake thermal efficiency (BTE) improved with blends up to B20, supported by the oxygenated nature of biodiesel, which enhanced combustion. At higher blends, however, brake specific fuel consumption (BSFC) increased due to the lower calorific value and higher viscosity of MC Biodiesel. Combustion analysis indicated advanced heat release and reduced ignition delay for biodiesel blends, reflecting their higher cetane number. In terms of emissions, CO and HC were significantly reduced, while NOx emissions increased with higher biodiesel fractions, consistent with the NOx–soot tradeoff reported in biodiesel literature. Overall, the findings suggest that MC biodiesel–diesel blends up to 20% can be effectively utilised in CRDI engines, offering improved combustion efficiency and reduced carbonaceous emissions, although further optimisation is needed to mitigate NOx formation.