Modelling of engine performance and emissions fueled by biodiesel blends

Abstract

The aim of this study is to investigate the modelling of engine performance and emissions fueled by biodiesel blends. Biodiesel blended with diesel, were introduced to mitigate its decreased power output, poor fuel atomization and increased nitrogen oxides emissions. Unfortunately, it has been difficult to obtain the best biodiesel blend level for optimal engine performance, since it sourced from a variety of vegetable oils whose fuel parameters and interactions differ considerably, causing variation in their combustion processes. The research has developed mathematical models, using Buckingham pi-theorem analytical method and experimental data to predict CI engine performance parameters {brake thermal efficiency (Bte) and carbon monoxide (CO) emissions, while, specific fuel consumption (sfc) and nitrogen oxides (NOx) emission fueled by different biodiesels’ diesel blends. The experimental tests were performed on factorial design method using a 3.5 kW one cylinder four stroke CI engine on a test rig connected to an eddy current electric dynamometer, running on biodiesels (WVO, canola, sunflower, oleander and coconut) with their blends (mixed at ratios by volume of biodiesel: diesel;10:90, 15:85, 20:80, 25:75 and 30:70) using the ASTM procedures. The results showed that engine fueled with biodiesel and their blends had lower Bte and CO emissions, while, sfc and NOx emission were higher, as compared those of diesel fuel.  The developed mathematical model predicted Bte, sfc, CO and NOx with error margins of 1.65, 15.98, 4.69 and 2.78 per cent respectively as compared to the experimental results.