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The article describes the process of developing a model for improving the operational performance of vehicles. The development of the model is based on the interconnection and mutual influence of the basic elements of the vehicle. Since the internal combustion engine is the source of energy and the driving force, its performance directly affects the operation properties of the vehicle. In turn, they mainly depend on the nature of the working process and engine parameters. Therefore, a change in the technical and operational indicators of the engine will entail a change in the operational indicators of the vehicle on which it is installed. An information model of the influence of engine parameters on vehicle operational indicators allows establishing that, for a certain time of operation and fixed values of operating modes, improvement of vehicle performance is possible by changing the technical and operational parameters of the engine. At the same time, considering the functioning model of the internal combustion engine as a certain multidimensional and multilevel system, it was found that the working process taking place in the engine and the design parameters of its mechanisms have the greatest impact on changing engine parameters. The main working process takes place in the engine cylinder. Therefore, the details of the cylinder-piston group will have the greatest impact on the change in the engine output parameters. The use of mathematical modeling in solving this problem allows developing a concept for improving the performance of a vehicle, and optimizing the process of choosing ways to upgrade a vehicle and engine.

The article considers the use of oils of vegetable origin alternative to mineral and synthetic oil products as a working fluid for hydraulic systems of agricultural machinery. When choosing vegetable oil, the use of camelina oil as a more affordable and economically cheap raw material is most appropriate. The main disadvantages of vegetable oils include low thermal and oxidative stability and unsatisfactory low-temperature properties. Therefore, the use of vegetable oils in hydraulic systems is possible only in the form of mixtures with mineral oil. To study the possibility of using vegetable-mineral oil as a working fluid for hydraulic systems of agricultural machinery, laboratory studies of the physical properties of camelina oil mixtures were carried out. The studies included the determination of the relationship between the kinematic viscosity and the density of the camelina oil mixtures from the temperature and were carried out in various proportions of the mineral hydraulic oil - multigrade oil hydraulic thickened (hydraulic oil - GM) and camelina oil (RyzhM) - 100 % GM, 90 % GM - 10 % RyzhM, 75 % GM - 25 % RyzhM, 50 % GM -50 % RyzhM, 25 % GM - 75 % RyzhM, 10 % GM - 90 % RyzhM, 100 % RyzhM. Determination of the physical properties of the camelina oil mixtures was carried out on a cryo-thermostat with viscosimetric LOIPLT-912, using an ANT-2 hydrometer and capillary viscosimeter VPZh^f, VPZh-2 in accordance with GOST R ISO 3675-2007 and GOST 33-2000 (ISO 3104-94) respectively. Based on the results obtained, it was found that red-and-oil mixtures with a ratio 90 % GM - 10 % RyzhM и 75 % GM - 25 % RyzhM according to viscosity-temperature properties and density can be used as substitutes for merchant mineral hydraulic oil GM. The results of the laboratory tests allow us to display the dynamics of the change in viscosity-temperature and density properties of red-and-oil mixtures of various concentrations.