Experimental Investigation of 2-Ethylhexyl Nitrate Effects on Engine Performance and Exhaust Emissions in Biodiesel-2-Methylfuran Blend for Diesel Engine

Biodiesel and 2-methylfuran (MF) exhibit significant potential as alternative fuels due to advancements in their production techniques. Despite this potential, the low cetane number (CN) of biodiesel–MF (BMF) blends limits their practical use in diesel engines due to poor auto-ignition characteristics and extended ignition delays. This study addresses this issue by investigating the impact of the cetane improver 2-ethylhexyl nitrate (2-EHN) on the performance and emissions of a BMF30 blend. The blend consists of 70% biodiesel and 30% MF, with 2-EHN added at concentrations of 1% and 1.5% to enhance ignition properties. The experiments were conducted on a four-cylinder, four-stroke, direct-injection compression ignition (DICI) engine at a constant speed of 1800 rpm with brake mean effective pressures (BMEP) ranging from 0.13 to 1.13 MPa. The results showed that 2-EHN improved the CN of the BMF30 blend, leading to earlier combustion initiation and longer combustion duration. At low BMEP (0.13 MPa), 2-EHN increased the peak rate of heat release and in-cylinder pressure, whereas at higher BMEP (0.88 MPa), these parameters decreased. The key findings include a reduction in brake-specific fuel consumption (BSFC) by 5.49–7.33% and an increase in brake thermal efficiency (BTE) by 3.30–4.69%. Additionally, NOx emissions decreased by 9.4–17.48%, with the highest reduction observed at 1.5% 2-EHN. CO emissions were reduced by 45.1–85.5% and soot emissions also declined. Hydrocarbon (HC) emissions decreased by 14.56–24.90%. These findings demonstrate that adding 2-EHN to BMF30 blends enhances engine performance, reduces key emissions, and offers a promising alternative fuel for diesel engines.