Leaf extract additives: A solution for reduction of NOx emission in a biodiesel operated compression ignition engine

Biodiesel has been proved as a promising solution among other alternate fuels in terms of its characteristics compared to diesel. The oxidation property of biodiesel results in the degradation of its quality. This problem can be solved by the addition of suitable antioxidants which improves the oxidation stability of the fuel. Usage of natural antioxidants offsets the defects in synthetic antioxidants, because they are renewable, nontoxic as well as cost effective. In the present investigation the effects of commercially available and cheap natural leaf extract additive such as Albizia Lebbeck (AL), Melia Azedarach (MA) and Psidium Guajava (PG) have mixed with jamun biodiesel blend (JOME20) at various concentrations like 500, 1000, 1500 and 2000 ppm to accelerated oxidation stability of the biodiesel blend. Characterization of biodiesel oxidation variability regarding different antioxidants is evaluated using Fourier Transform Infra-red (FTIR) spectroscopy by analyzing the FTIR spectrum regions of C-H bonds of the respective antioxidants/biodiesel blends. The AL dosed with 20% of jamun biodiesel (JOME20) enhances the oxidation stability by 25.27%, when compared to those of JOME20 without any antioxidant. The order of effectiveness of antioxidants at 1000 ppm concentration with JOME20 is obtained as AL > MA > PG. Further, the experiment is conducted with jamun oil methyl ester (JOME) as a fuel in CI engine are studied. Engine tests are performed using the blends of 20% Jamun Oil Methyl Ester (JOME20) and 100% Jamun Oil Methyl Ester (JOME100) with diesel as fuel. The performance results revealed that improved brake thermal efficiency and marginally lowered specific fuel consumption for JOME20 blend compared to diesel. The emission parameters such as CO, CO2, HC and smoke are decreased considerably. But, the NOx is increased by 10.6% compared to diesel. Therefore, in the present study aims to control the NOx emission by using natural leaf extract additives mixed with JOME20 blend. Finally, it is concluded that JOME20 with 1000 ppm of AL is showed reduction of NOx emission up to 8.67% compared to diesel. Further, the oxidation stability of the biodiesel is increased significantly. (C) 2019 Elsevier Ltd. All rights reserved.