Effect of biodiesel addition in a blend of isopropanol-butanol-ethanol and diesel on combustion and emissions of a CRDI engine

Abstract

ABSTRACT The increasing demand for energy and the fact that petroleum, which is the most used energy source, has a limited reserve, have led researchers to search for new and renewable energy sources. In this context, biofuels such as biodiesel and bio alcohols have been studied and used in internal combustion engines for a long time. However, with the developments in technology, the production and use of such alternative fuels in different engine technologies is still a subject of research. In this regard, isopropanol-butanol-ethanol (IBE) has received an increasing attention over standard alcohols and its potential as a substitute for other alcohol fuels in internal combustion engines has been researched recently. Therefore, the purpose of the experimental study is to investigate the effect of biodiesel addition at rates of 20% and 40% by volume in a blend of IBE (30% v/v) with petroleum-based diesel (70% v/v) on the combustion and emission characteristics of a single-cylinder common-rail direct injection engine at constant engine speed of 2400 rpm and 60% load conditions. Experimental results showed that all blended fuels presented a potential to reduce smoke opacity by 27% − 41%, CO emissions by 44% − 66% and unburnt HC emissions (up to 31.8%) but increase NOx emissions by 5% − 24.6% compared to diesel. However, adding biodiesel caused to a slight increase in smoke opacity and CO emissions while decrease in unburned HC and NOx emissions compared to the blend of IBE and diesel. Combustion analysis also showed that the use of blended fuels led to the increase of peak cylinder pressure (by 7%) and the significant improvement in the rate of heat release was observed, which further increased with the addition of biodiesel to blend of IBE and diesel. It was concluded that ternary blends was performed better than the blend of IBE and diesel while biodiesel addition was found to be beneficial in terms of reduction of unburnt HC and NOx emissions along with improved performance.