Impact of Aluminum Nitrate and Graphene Oxide Nanoplate on Performance and Emission Characteristics of a CRDI Diesel Engine Powered by Industrial Leather Waste Fat Biodiesel

This study investigates the effect of nano-additives, such as aluminum nitrate (Al(NO₃)₃) and graphene oxide nanoplate (GONP), on the performance and emissions of a common rail direct injection (CRDI) diesel engine at maximum load. It also compares injection timings (IT) at 21, 23, and 25° crank angle (CA) before top dead center (bTDC) with exhaust gas recirculation (EGR) rates of 10, 15, and 20%. The engine uses blends, such as B50 (50% diesel and 50% leather industrial waste fat biodiesel (LIWFB)), B50 + Al(NO₃)₃, and B50 + GONP. The results revealed that adding Al(NO₃)₃ and GONP increases cylinder pressure and heat release rate (HRR). The B50 + GONP blend increases brake thermal efficiency (BTE) by 2.75% over the LIWFB mixture at 10% EGR and 1.42% over B50 + Al(NO₃)₃. It also lowers brake-specific energy consumption (BSEC) by 1.06% and 0.583%, compared to LIWFB and B50 + Al(NO₃)₃. Adding GONP to the B50 blend reduces explicitly emissions, such as smoke by 9.09%, 10.17%, and 3.53%, HC by 45.45%, 11.11%, and 7.69%, and CO by 28.99%, 10.44%, and 5.51% compared to diesel, LIWFB, and B50 + Al(NO₃)₃ at 25° CA and 10% EGR. The LIWFB produced 61.72% lower NOx emissions than diesel at 23° CA and EGR at 20%.