Experimental Research of Environmental Indicators and Combustion Processes of Diesel Engines for the Case of Application of Biodiesel and Bioethanol

Biofuels are of increasing importance, because they do not affect the carbon dioxide (CO2) balance. Biodiesel and bioethanol are considered fuels of the future, because of their positive influence in terms of the environment. The paper presents the results of experimental research on environmental indicators and the combustion processes in a diesel engine when using biodiesel and bioethanol as alternative fuels. The aim of the research is to compare the concentrations of harmful gaseous products of combustion in the emission of diesel engine exhaust gases, for the cases when conventional diesel fuel, biodiesel or bioethanol is used. A modified experimental IC engine was used for the purpose of this research in order to realize both a diesel and an otto cycle in the same engine. During the combustion of diesel fuel or biodiesel, the engine works according to the diesel cycle, and during the combustion of bioethanol, the engine works according to the otto cycle. This paper presents the results for two loads, 75% and 100%. The results lead to a conclusion that the full potential of biodiesel and bioethanol, in terms of reducing harmful emissions of gaseous combustion products, cannot be used if these biofuels are used as pure fuels, but it is better to use them as additives for conventional fuels.