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The air temperature has a significant effect on the warming up of the engine of automotive vehicles. To study this process, comparative experiments on the functioning of tractors in different operating modes were carried out. The value of the coolant temperature was taken as a parameter characterizing engine warm-up. In our studies, the heating of the coolant was considered complete when the temperature at the outlet of the tractor blockhead reached 85 degrees Celsius. The ambient temperature varied from plus 20 to minus 30 degrees. The effect of the load modes of its operation was taken into account on the duration of the tractor engine warming up. The results obtained show that the warm-up of the tractor engine at idle speed has a protracted nature and does not always have a positive result. The process can be intensified by operating the tractor engine under load and using an insulating cover. This reduces the duration of the warm-up process and significantly reduces the unproductive downtime of the tractor.

For research, we used a root crop grinder with improved operational properties, which ensures the grinding of juicy vegetable raw materials (fodder, sugar and semi-sugar beets, rutabaga, turnips, carrots, potatoes) into pieces in the form of a parallelepiped of sizes corresponding to zootechnical requirements. The rationale for the action of forces on tubers in a stationary reference system in the process of cutting potatoes is given, the shape of which, with some assumption, is accepted as a ball. Based on the laws of mechanics, the authors obtained an analytical expression of the value of the optimum angle of inclination of the contradiction of the cutting apparatus of a particular chopper, depending on the size of the tuber, the height of the horizontal knife and the coefficient of friction. Given the values of these parameters, it is possible to fully carry out a theoretical and practical analysis of the limiting value of the angle of inclination of the contradiction of the cutting apparatus and its effect on the rolling of the tuber, as well as on its pinching.

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Introduction. The development of the agro-industrial complex is impossible without creating innovative techniques and technologies. The key role in technical support of agricultural production processes is played by machine-tractor aggregates. One of their most important operational characteristics is reliability, i.e. the ability to perform specified functions, keeping over time the values of the operational indicators within the required limits. Materials and Methods. The object of the study is the reliability of machine-tractor aggregates. The methods of mathematical modeling were used for the study. The general patterns were used for special cases, taking into account the prediction of changes in parameters over time. The analytical description of machine-tractor aggregate operation reliability was based on stationary random and correlation functions. Generalized patterns were used to construct mathematical reliability models using the results of predecessor (analogue) tests. Optimal reliability of the machine-tractor aggregate operation was determined on the basis of the mathematical model of object resource. Results. There are obtained analytical dependences for the prediction of changes in reliability parameters of machine-tractor aggregate operation over time. The methods for creating reliability mathematical models are developed. Conditions affecting the functioning of the research object are determined. Discussion and Conclusion. The analysis and synthesis of research in this science field and the obtained mathematical models show that to achieve high results it is necessary to decrease the variance of factors affecting the reliability of machine-tractor aggregates.