The random nature of the load is the main cause of deterioration of energy parameters and technical and economic indicators of machine-tractor units (MTU). Oscillations of the load lead to an increase in energy costs for technological processes. Direct fuel and energy costs should be determined and predicted with a high degree of reliability, taking into account the specifics of the work of the MTU and the dynamics of its performance of technological processes. The identification and optimization of energy costs of the MTU will ensure an increase in the efficiency of the technological processes and technologies of cultivation in crop production. The subject of the study is the development of mathematical models for determining and optimizing the direct energy costs of MTU equipped with advanced gas turbine engine (GTE) engines. The purpose of the research is to develop a methodology for determining the direct fuel and energy costs of MTU, taking into account the probabilistic nature of the load. The novelty of the research consists in the developed mathematical models and calculation algorithm, as well as optimization of the direct fuel and energy costs of MTU with GTE. The proposed methodology is developed on the basis of a systematic approach, generalization, and analysis of experimental data, mathematical modeling of processes. Experimental studies were carried out in laboratory facilities and in the field using modern measuring instruments and recording experimental data. The proposed methodology allows, with a probability of 0,90-0,95, to predict the optimal values of the direct fuel and energy costs of the MTU with GTE. As an example, the article gives examples of calculation and optimization of direct fuel and energy costs of plowing unit consisting of a Kirovets tractor with a GTD-350T gas turbine engine and a PNI-8/9-40 plow at various levels of turbocharger speed. It is established that at the 100 % level of the turbo compressor speed and the variation of the load variation coefficient from 0 to 0,333, the optimal values of the direct fuel and energy costs of the plowing unit increase from 543,0 to 723,12 MJ/ha. The same trend of increasing the direct fuel and energy costs of MTU is also observed in other levels of implementation of the turbo GTE turbocharger speed. It should be noted that with a decrease in the level of implementation of the turbocharger GTE's speed, direct fuel, and energy costs are increasing. The proposed methodology allows to determine and optimize the values of direct fuel and energy costs of MTU with GTE taking into account the probabilistic nature of the load under the specific conditions of their operation.

The soil-cultivating machine-tractor unit undergoes continuously changing external influences that lead to fluctuations in the speed of movement, slippage of the tractor's driving wheels, loading of the transmission, and increased fuel consumption. The main sources of disturbances that cause the oscillations of the tractor are the unevenness of the traction resistance of the tillers and the unevenness of the field microprofile. The purpose of the research is to improve the process of functioning of the soil-processing machine-tractor unit by modeling of the influence of external action. The mathematical model of the process of operation of a wheeled tractor in the traction mode of operation is a machine-tractor unit in the form of a dynamic system with two input forces, determined by the load on the working elements and the roughness of the relief. The mathematical model includes the equations of the motor and the regulator, the clutch, the power transmission, the driving wheel and the longitudinal-vertical oscillations of the tractor. The solution of the mathematical model of the machine-tractor unit is based on the fourth-order Runge-Kutta numerical integration method at a constant step. Calculations are made for the motion of the unit with periodic sinusoidal disturbances applied to the input of the model. As a result of calculations, it is determined that the effect of the microfield of the field and the traction resistance of the working bodies on the performance of the machine-tractor unit is different. The greatest amplitudes of vertical accelerations are achieved due to the effect of field unevenness. Fluctuations in the speed of movement, hectare fuel consumption, engine torque are caused by the periodic component of traction resistance of low frequency, and slippage and driving torque of the wheels - as well as unevenness of the field microfilm. The average values of the slippage of the tractor's driving wheels and hectare fuel consumption are mainly affected by the oscillations of the traction resistance. The use of diagonal-parallel tires instead of radial makes it possible to reduce the slipping of the tractor's drive wheels from 24 % (when working on serial tires) to 16 % (on test tires) and to reduce the hectare fuel consumption by 6 %.

The work is devoted to the theoretical study of the elastic properties of tractor wheels and the analysis of the effect of air pressure in the tires and vertical loads on the wheel axles. According to the developed computer program, which allows to implement the method of calculating the characteristics of the elastic properties of tractor wheels with pneumatic tires proposed in this work, one-factor and complete factor computer experiments of two types were carried out. In computer experiments of the first type, the dependences of the elasticity coefficients of a number of elastic wheels were investigated when operating on the practically non-deformable basis of tractors MTZ-82 and MTZ-142 from the air pressure in the tires at different values of the vertical dynamic loads on the axes of the corresponding wheels of tractors. In computer experiments of the second type, the dependences of the elasticity coefficients and the normal deflection of the wheels with tires of different sizes from the air pressure in the tires at constant values of the vertical dynamic loads on the wheel axles were investigated. In computer experiments of both types, the deviations of the elastic properties of elastic wheels found by calculation are within the limits of the accuracy of measurements of the experimental data. Based on the results of computer experiments of the first type, regression equations were obtained reflecting the dependence of the elasticity coefficients of the elastic wheels studied on the air pressure in the tire for various values of the vertical dynamic loads on the wheel axes. According to the results of computer experiments of the second type, equations of regression of the coefficients of elasticity and normal deflection of wheels with tires of different sizes from air pressure in tires at constant values of vertical dynamic loads on the wheel axle are obtained. The high correlation values for these regression equations indicate the high importance of the relationships in the found correlation dependencies. The application of the proposed calculation method makes it possible to simplify and shorten the work on the choice of tires of optimum sizes to different tractors, taking into account the specific conditions of their operation. It was calculated that wheels with tires 18.4R38 are optimal on the rear axle of the MTZ-82 tractor.

There was developed a new single-zone model of the fuel combustion process, based on the equations of chemical kinetics, which takes into account in more detail the features of the internal chamber processes of internal combustion engines. The combustion process is considered as a set of successive oxidation reactions to carbon dioxide and water of groups of active fuel molecules proceeding according to the Arrhenius law. The number of active molecules of fuel entering into the reaction depends on the total number of fuel molecules, the current mixture temperature and the conditional activation energy, varying depending on the fraction of burned fuel. The conditional duration of oxidation of this group of active molecules is assumed to depend not only on the total number of fuel molecules, but also on the volume of the combustion chamber, the number of oxygen molecules, the number of molecules of inert components and turbulence inside the combustion chamber. The heat released during the oxidation of each group of active fuel molecules is determined through the lower heat of combustion of the fuel and is expended to increase the temperature and pressure of the mixture in the combustion zone. At each step of the calculation, the number of molecules of all substances is corrected as a result of fuel burn-out. A special feature of the model is the introduction of a new parameter that takes into account the time factor at the molecular level, the conventional duration of the oxidation reaction of the active molecules of the fuel. A new mathematical model is used as the basis for the algorithm for the developed program for calculating the operating cycle of an accelerated diesel engine with a prescribed law of mixture formation. Calculations of the influence of the temperature of the fresh charge after the charge air cooler on the duty cycle of the forced diesel in the range from 360 to 430 K are performed. According to the results of the calculation, it is established that the best indicator characteristics of the working cycle are reached at a temperature of 360 K. Indicator diagrams of pressure in the cylinder and the laws of heat generation, obtained by calculation correspond with known experimental data.

The main preparation of the soil for protective forest plantations on agricultural fields and tractor pass of gully slopes with the steepness up to 12° in the regions of insufficient and unstable moistening is characterized by a low degree of crumbling of the soil layer, when using plows , high energy and material intensity, multi-operation (plowing, deep loosening, destruction of soil blocks). Plowing across slopes with a steepness of more than 4-6° is made only under a slope, i.e. each working stroke is idle, and this reduces the productivity. The design of a combined tillage machine is offered, it is the hinged ripper plow PRN-40, replacing plows of general purpose PLN-4-35 and the plant PPN-40, the hinged ripper RN-80, the cultivator KRT-3 or the heavy disc harrow BDNT-3, which produces a deep layered cultivation of the soil (plowing to a depth of 25...27 cm and loosening the subsoil layer by 25...40 cm) and active circulation of the soil layer both downward and upward along the slope to 12...15 °; excluding additional treatment for the purpose of destroying soil blocks. In the plow-ripper PRN-40, the working parts of the passive (the body with the shortened blade and the deep cutter) and the active (rotary ripper) operation are used. They use power of the tractor engine through its propulsors and PTO separating the plowing process into separate operations performed at different rates of impact and subject to a layer of various non-energy-intensive types of deformation.

The determining factor for increasing the yield of agricultural crops is the quality of sowing, which is ensured by the coordinated work of the system: the sowing apparatus - seed pipe - coulter. The task of the sowing device is to consistently give out a given number of seeds to the seed pipe by the area of supply for this method of sowing. Serial seeders do not provide the minimum sufficient seeding rate for small-seed crops, which leads to overspending of expensive, scarce seeds and reduced yields due to thickening of the crop. Based on the results of the theoretical studies and physical modeling, a vertical disc seeder was developed, which ensures the seeding of small-seed crops. The sowing apparatus represents a disc with a diameter of 93 mm along the outer perimeter, which contains cells in the form of a sector of a semicircle with a radius of 3 mm, a depth of 2 mm. Laboratory studies on alfalfa seeds showed that when the disc rotates, the seeds begin to fall out of the cell under their own weight, when the cell is at an angle of 35° with respect to the horizontal line. To carry out field research, a seeder was built on a frame, in which seven seed sections with individual bunkers were installed in two rows. Seeding width is 0.9 m. The drive of the sowing units is carried out by chain transfer from the support wheel through the gearbox. The sowing discs are connected to the shafts by individual couplings, which made it possible to sow with a different width of the rows. The field experiment was conducted on the sowing of the zoned alfalfa Omskaya-7 with inter-row spacing of 0,15 m, 0,60 m, and 0,90 m in triplicate repetition. According to the results of the field experiment, it was found that the sowing disc with cells with a radius of 3 mm and a depth of 2 mm of 8 pieces on the disc, and its rotation frequency of 1,53 rpm, when sowing with different rows, consistently provided for 1 meter of sowing on average 33 plants at field germination of 84,4 %.

Complex mechanization of selection and experimental works allow to significantly increase the volume of obtaining high-quality seeds and improve the efficiency of all breeding activities. During the harvesting of crops, from the plots everyday up to 5000 items in bunches and up to 1500 pieces of beets are harvested. The total weight of the harvest per day is within 500 kg. Harvesting of plants from the plots of the first stage is carried out manually by cutting the plants with a sickle, scissors or pulling out with the root system. The number of samples requiring analysis for the season is estimated by many thousands, for example, only in selection nurseries are prepared for each crop up to 15-20 thousand plants. This is the most time-consuming operation in breeding. The number of plots in the II stage also reaches several thousand pieces for each crop. The attempt to mechanize the cleaning of single-breed plots at the I-II stages, both in Russia and abroad, has not yet yielded results for mass and effective application. In this regard, the VIM started developing a new domestic technical means for harvesting grain crops at the I-II stage of breeding in 2011 to reduce the cost of the technological process in primary seed production using elements of existing mowers and trimmers. Prototype of the new mowers under the brand name ТС-0,2 was made by MZOK VIM plant. Taking into account the accumulated experience in the study of the ТС-0.2, in 2017, the work on its modernization was carried out in the VIM. In addition to the elimination of deficiencies in the design introduced additional elements to improve the work such as the table-flooring for cut stems. The technical parameters of the trimmer are justified on the basis of physical and mechanical, dimensional and morphological properties and characteristics of the stem of the selection crops, the size of the selection plots and the size of the stems in a row. Harvesting machines of this type are quite popular, but, unfortunately, their production is not mass and this does not allow to organize their mass production.