Physicochemical Properties of Diethyl Ether—Sunflower Oil Blends and Their Impact on Diesel Engine Emissions

Abstract

In this paper, an analysis of the physico-chemical properties of diethyl ether/sunflower oil blends, as well as changes in emissions in work with AD3.152 diesel engine, were realized. The following properties of tested blends have been examined in detail: density (ρ) at 15 °C; kinematic viscosity (v) at 40 °C; cold filter plugging point (CFPP); lower heating value (LHV); flash point (FP); and surface tension (ϭ). In this research, different blends of diethyl ether (DEE) with sunflower oil (SO) in ratios of 10:90, 20:80 and 30:70% by volume were chosen. It was confirmed that DEE impacts significantly on reducing of SO viscosity. Furthermore, the density, as well as the surface tension of tested blends, have been reduced significantly when DEE was blended with SO. In this way, DEE impacts on better atomization of the SO injected into the combustion chamber. It was confirmed that DEE addition improves the low-temperature properties of SO significantly, which indicates the possibility of also using such blends in the winter season. On the other hand, the flammable DEE additive significantly lowers the flash point of the tested blends, which requires compliance with the transport safety rules applicable to gasoline. An engine tests carried out in condition of its partial load i.e., for 80 and 120 Nm, showed that combustion process of DEE/SO blends is more and more similar to the combustion of diesel fuel when adequately higher content of DEE is blended with SO. In particular, it was confirmed that the highest smoke concentration was observed for the engine operated with SO. However, 30% addition of DEE to SO brings this smokiness significantly closer to the value typical for the engine operated with diesel fuel. Additionally, concentration of unburned hydrocarbons (THC) and nitrogen oxides (NOx) are comparable for diesel fuel and DEE/SO blends.