A core correlation of spray characteristics, deposit formation, and combustion of a high-speed diesel engine fueled with Jatropha oil and diesel fuel

Abstract

The benefits and advantages of bio-based fuels according to the research results of scientists and researchers related to the stable maintenance and sustainable development for the purpose of harmonizing the environment and life is an indisputable fact. Experimental studies on the use of bio-based fuels for engines in the long term should be thus thoroughly conducted to obtain the fullest results of economic-technical features and emissions, to name just a few. In this paper, a state-of-the-art analysis on the core correlation based on the trilateral relationship of spray characteristics, combustion, and emissions of a high-speed four-stroke diesel engine running on Jatropha oil (JO) in two cases of preheated and unpreheated in comparison to diesel fuel was investigated and carried out. Tests included two phases: (i)-tests of spray characteristics, analysis of combustion and emissions for engine fueled with preheated JO, unpreheated JO, and DF at the first hour and after 300 h of endurance test for engine, (ii)-analysis of formed deposits in the nozzle orifices and piston crown after 300 h of operation. As a result, huge deposits formed in the injector orifices and piston crown based on optical observation by SEM in case of using unpreheated JO as fuel were found, followed by preheated JO and DF. In addition, a sharp increase in spray penetration length and a significant decrease of cone angle for unpreheated JO compared to preheated JO and DF were also indicated, whereas thermal efficiency of the test engine for preheated JO, unpreheated JO, and DF was reduced by respectively 1.68%, 4.38%, and 0.98% after 300 h of operation. For emission data, negative changes such as a more reduction of NOx along with a higher augment of CO, HC, and smoke with unpreheated JO than those of preheated JO and DF were reported. In closing, core correlation as well as trilateral impacts of accumulated deposits, spray characteristics, and combustion were thoroughly demonstrated and deeply analyzed.