Impact of ammonia energy fraction on improving thermal efficiency and emissions of ammonia/biodiesel in dual fuel diesel engine

Abstract

Ammonia (NH3) and Cashew Nut Shell Oil (CNSO) biodiesel blends are used in a four-stroke, single-cylinder Internal Combustion (IC) engine to examine combustion characteristics, engine performance, and emissions. NH3 is an encouraging alternative fuel, considering its high energy density and carbon neutrality. Biodiesel derived from cashew nut shells is an environmentally friendly fuel option with substantial unsaturated fatty acid content. An investigation was executed with NH3 at a flow rate of 3 and 6 liters per minute (LPM) at 50 % CNSO, 50 % diesel (50CNSO50D), and 100 % CNSO. With the addition of NH3 to diesel, peak in-cylinder pressures increased from 63.412 bar to 68.87 bar at 3 LPM and 70.239 bar at 6 LPM, respectively. In comparison to diesel, CNSO biodiesel exhibited a minor decrease in peak pressure (62.034 bar) and a slight delay in ignition. Compared to diesel, thermal efficiency increased significantly with NH3, rising from 31.1 % to 33.3 % and 34.8 % at 3 and 6 LPM NH3, respectively.CO emissions analysis revealed that CNSO biodiesel reduced emissions to 17 g/kWh, comparatively diesel's 19 g/kWh, with NH3 further reducing them. The NOx emissions from CNSO biodiesel blends are higher (16 g/kWh for CNSO) than diesel (13 g/kWh), but the addition of NH3 reduces NOx emissions across all fuels. The low energy content of CNSO leads to higher CO2 emissions, but NH3 reduces these emissions. CNSO and NH3 blends had lower hydrocarbon (HC) emissions than diesel. It has been found that using NH3 and CNSO biodiesel improves the performance of diesel engines and reduces emissions, contributing to the reduction of global emissions and helping to create a more sustainable future.