Assessment of the exergy, emissions, and combustion characteristics of a diesel engine operating on low-glyceride biodiesel blended with diesel fuel

Abstract

The behavior of biofuels depends on glyceride content, water content, viscosity, density, and other properties that produce different effects on emissions and fuel performance. Therefore, this work performs an experimental evaluation of the performance of low glyceride palm oil biodiesel blended with diesel fuel operating in a compression ignition engine based on an analysis of exergy, emissions, and combustion characteristics. 90 tests were carried out, operating the engine with diesel/biodiesel 90/10% (B10), 80/20% (B20) and 50/50% (B50) fuel blends, under two load conditions at engine speeds of 1500, 1800, 2100, 2400 and 2700 rpm. Among the main results were a higher concentration of carbon monoxide (CO) and carbon dioxide (CO2) was obtained for B10, and lower concentration of nitrogen oxides (NOx) compared with fuels B20 and B50. Moreover, the increase in the fuel blend, allows better burning in premixed phase and reducing burning in the diffuse phase, improving the combustion process of the engine, mainly due to less delay in fuel injection associated with the low content of glycerides in the blend. Concluding that the decrease of glycerides in biodiesel provides adequate performance, a considerable decrease in emissions and homogeneous combustion when blended with conventional diesel.