Analysis of Internal Combustion Engine Performance Using Design of Experiment

This research paper presents a theoretical study on the effect of the blending of petro-diesel with locally made biodiesel on the engine's performance and emissions from a statistical point of view. The main purpose of this study is to study how the engine performance changes with the blending of biodiesel with ordinary diesel from the performance as well as the most influential factors point of view using statistical methods. The study was conducted at a stoichiometric air-fuel ratio, engine speed range from 1000 to 3000 rpm and with diesel-biodiesel fuel blends of 0% (pure diesel), 5%, 10%, 20%, 30%, 40%, 50% and 100% (pure biodiesel). The parameters studied were brake torque, specific fuel consumption, and fuel mass flow rate, oxides of nitrogen, carbon dioxide, and particulate matter. The results show that engine brake torque increases with the addition of biodiesel up to 5% BD with a 0.5% improvement at low speed and up to 2.5% at higher speeds. The same trend is for specific fuel consumption with 0.2% and 2.0% at lower and higher speeds, respectively. From the emissions' point of view, oxides of nitrogen increased from 12.5% at 5% BD to more than 200% at 100% BD; PM emissions were reduced with the addition of biodiesel while those for CO2 were increased. DOE analysis showed that biodiesel percentage has the most significant influence on the engine performance and emissions compared with engine speed except for the brake torque.