Novel investigation on atomization, performance, and emission characteristics of preheated jatropha oil methyl ester and ethyl ester

The increase in diesel fuel prices has compelled engine users to switch to cost-effective alternative energy sources, particularly in developing countries. This study aims to produce jatropha oil biodiesel extracted from the jatropha curcas plant using a catalyst as methanol and ethanol. Since the methyl ester of jatropha oil (JOME) has been extensively researched as an alternative fuel, however, there has been little research into the ethyl ester of jatropha oil (PJOEE) as a fuel in both unheated and preheated conditions. The yielding of JOME and JOEE were found as 93.52% and 98.23%, respectively. An increase in fuel inlet temperature from 30 °C to 90 °C causes a reduction in density, viscosity, and surface tension by 6.75%, 67.31%, 15.75% for methyl ester, and 6.61%, 66.39%, 15.38% for ethyl ester. Its impact on atomization, performance, and emission was investigated in the current study. A laser-diffraction-based setup named Malvern spraytec was used to measure Sauter mean diameter (SMD) at various ambient conditions. It was discovered that preheated ethyl ester and methyl ester had lower SMD than unheated methyl ester and ethyl ester, as well as diesel fuel. Moreover, the brake thermal efficiency of PJOEE was 4.1% higher than diesel at 6 bar of brake mean effective pressure (BMEP) and a decrease of 7.1% in brake-specific fuel consumption (BSFC) than neat diesel. Furthermore, engine emissions revealed that preheated ethyl esters of jatropha oil could reduce carbon monoxide (CO), unburned hydrocarbon (HC), and smoke opacity emissions at all BMEPs, followed by PJOME, which was nearly as effective as neat diesel except for NOx. Subsequently, a brief cost analysis was carried out, that indicated the cost of generating 1 kWh of energy preheating jatropha oil methyl and ethyl ester was 44.16% and 42.92% less than diesel fuel, with better performance and lower emissions. Thus, preheated methyl ester and ethyl ester of jatropha oil can be excellent substitute fuels for unmodified diesel engines.