## 1 Introduction  
For many years the research on the use of canola oil in diesel engines has been carried out [1, 2, 3, 4, 5, 6, 7, 8, 9]. Unfortunately, such important properties of canola oil such as viscosity, density, surface tension, calorific value, flash point, fire point and cetane number in terms of its application for diesel engines are largely different from those of diesel fuel [10, 11, 12]. As a matter of fact, canola oil can be esthrified and the obtained esters have physicochemical properties similar to those of diesel fuel. The drawback of this type of solution is that the transesterification process is a high energy-consuming one and its side effect is the production of significant amounts of glycerine. Moreover, a stable supply of plants must be provided as a source of oilseeds for production (which is difficult due to the vegetation cycle of plants). Thus, it seems that a better way to use canola oil as a fuel for diesel engines is to modify its physicochemical properties [10, 11, 12, 13, 14, 15, 16]. There is a lot of research in the literature on the modification of these properties of canola oil using different methods [10, 11, 12, 13, 14, 15, 16, 17, 18, 19]. These methods can be divided into two groups [13, 14, 15, 16, 17, 18, 19]. One group of the methods was to change the form of canola oil, for example, by annealing its microemulsion [20]. Canola oil in the form of microemulsion is characterized by smaller values of physicochemical parameters. The second methods group of canola oil properties modification is based on the addition to oil different types of substances which caused its physicochemical properties to be closer to those of diesel fuel [10; 11; 12; 13; 14; 15; 16]. The canola oil is the mixture of different mainly unsaturated and saturated fatty acids [21; 22; 23]. The molecules of these aids contain one hydrophilic group, -COOH, and different types of the hydrophobic hydrocarbon group. In the case of the unsaturated fatty acids in the hydrocarbon group there are the double bonds between some carbon atoms [24]. These bonds decrease the hydrophobic character of hydrocarbon chain insignificantly. It seems that such properties of canola oil, as among others, surface tension, density and viscosity should be proportional to these properties of the canola oil components. However, some differences between these psychochemical properties of canola oil and its components were found [21; 22; 23]. This fact is important for understanding the reduction in the surface tension, density and viscosity of canola oil by the addition of some substances [13; 14; 15]. In our previous studies the addition of n-hexane to canola oil was proposed to decrease its viscosity, density and surface tension as well modify its wetting properties [13; 14; 15]. The n-hexane has a small viscosity (0.3101 mPa\(\cdot\)s), density (0.659 g/cm\({}^{3}\)) and surface tension (18.49 mN/m) and it spreads completely on each solid, even on such low energetic one as polytetrafluoroethylene (PTFE) [15; 25; 26]. It seems that the addition of n-hexane to canola oil should reduce its viscosity and density values to those of diesel oil. It turned out that even 20% of n-hexane content in canola oil did not meet these conditions. For example, the viscosity of the mixture of canola oil and n-hexane with this content is almost four times larger than that of diesel fuel [15]. The n-hexane is a hydrophobic liquid whose surface tension results practically from the dispersion intermolecular interactions [26]. For this reason n-hexane affects the interactions between the hydrocarbon chains of fatty acids to a greater extent than the acid-base one. Therefore, it seems that apart from n-hexane, the addition of ethanol to canola oil can change its physicochemical properties to a greater extent. Thus, the purpose of our studies was to determine the viscosity, density, surface tension and wetting properties of the canola oil mixture with n-hexane and ethanol with regard to these properties of the canola oil components.