A Comparative Study of <i>Litchi‐chinensis</i> Biodiesel–Diesel Blends With Alcoholic and Nanoparticle Additives on Engine Performance, Emissions, and Coefficient of Friction

ABSTRACT Environmental hazards and the growing demand for fossil fuels are two major current concerns. The current global situation requires extensive research on renewable fuels. In this experimental study, we investigated different blends of biodiesel derived from litchi seed oil, which is inedible, for engine performance, emissions, and tribological characteristics. Litchi chinensis biodiesel was synthesized from litchi seed oil through a microwave‐assisted transesterification. First, a 30% biodiesel–diesel blend (B30) was prepared and mixed with ethyl ethanoate (EE) in the proportions of 10% (B30EE10) and 15% (B30EE15) by volume. Additionally, 100 ppm of aluminum oxide (abbreviated as Al) nanoparticles were added in all blends (B30Al, B30EE10Al, and B30EE15Al). All six blends were investigated for engine performance and emissions on a diesel engine. The coefficient of friction (COF) was measured using a four‐ball tribo‐tester for a 5% by volume fuel blend in SAE‐40 lubricant (ASTM D4172 standard). Engine performance analyses indicated that, compared to diesel, the B30EE10Al gives most promising results at an engine speed of 1500 min −1 in terms of engine performance and emissions with 4.97% higher brake thermal efficiency and by reducing brake‐specific fuel consumption, and CO, HC, and NO x up to 15.27%, 30.24%, and 3.92%, respectively. Four‐ball tribo‐tester results reveal that 5% B30Al in SAE‐40 oil has the lowest COF of 0.066, which is 34% less than that of diesel. Overall, the addition of aluminum nanoparticles and EE10 in Litchi chinensis biodiesel blend has improved the fuel quality in terms of performance and emission properties.