Influence of Waste Cooking Oil Methyl Ester Biodiesel Blends on the Performance and Emissions of a Diesel Engine

The present study deals with the performance and emissions of conventional diesel fuel and biodiesel produced from waste cooking oil and their blends (B10, B15). The waste cooking oil methyl esters synthesis has been (WCOME) carried out by a single step alkali catalysed transesterification reaction. Significant physico-chemical properties have been measured and compared against the ASTM D6751 standards. The tests have been performed on a single cylinder, direct injection diesel engine at a constant speed 1500 ± 50 rpm. During the tests, brake thermal efficiency, specific fuel consumption, exhaust gas temperature, exhaust emissions are measured. The experimental results revealed that, relative to diesel, WCOME fuel blends show 1.7–4.14 % decrease in the brake thermal efficiency and 2.18–5.57 % increase in the brake specific fuel consumption due to higher density and kinematic viscosity of WCOME, which reduces the fuel atomization rate. Moreover, most of the constituents of exhaust gas such as CO (13.67–16.89 %) and HC (4.35–11.84 %) along with greenhouse gas such as CO2 (8.34–17.39 %) are reduced in case of all the blends. However, an increase in the NOx emissions (0.3–4.2 %) is mainly due to the higher cetane number of fuel blends, which decreases the ignition delay. The results of this study revealed that WCOME blends show fewer exhaust emissions with a little compromise in the performance of the engine.