Usefulness of Rapeseed Oil Modified by n-Hexane and Ethanol as Diesel Fuel

An attempt was made to adapt the physical and chemical characteristics of rapeseed oil (Ro), including its density, viscosity and surface tension to diesel oil in the aspect of its use as a biofuel in diesel engines by adding 10 and/or 15 percent n-hexane to the oil and contacting the obtained mixture with ethanol. After establishing an equilibrium of ethanol extraction in the phase containing a mixture of Ro and n-hexane and the mixture components in ethanol, measurements of the viscosity, surface tension and density of oil phases were performed. The obtained values of these physicochemical parameters for the Ro and n-hexane mixture phase were close to those of diesel oil. Next, engine tests were carried out on the Ro+n-hexane mixture after its contact with ethanol under real driving conditions. The tests showed that the mixture of rapeseed oil with 10% n-hexane in contact with ethanol achieved the highest torque and power values among all Ro-based fuels, and that the decrease in these parameters compared to diesel fuel was the smallest. Moreover, compared to Ro and the mixture of Ro with 10% n-hexane, a higher energy efficiency was obtained, which is due to the favorable physicochemical properties of the fuel—the reduced viscosity and improved volatility.