PROSPECTS FOR OBTAINING GAS MOTOR FUEL FROM BIOGAS OF ANAEROBIC DIGESTION OF AGRICULTURAL WASTE

The ability of gas hydrates to concentrate gas into a solid chelate structure and the properties of self-preservation of gas hydrates at negative temperatures allows us to consider the possibility of developing a method for the utilization of biogas, environmentally safe storage and transportation of biomethane. (Research purpose) The research purpose is in substantiation the technological possibilities of obtaining synthetic mixed gas hydrates of biogas components, their storage and transportation based on the analysis of the existing regularities of the formation of gas hydrates in time, temperature and external pressure. (Materials and methods) The article presents the accumulated results of studies of the process of obtaining artificial hydrates of natural gas and methane- containing gas mixtures at various initial static pressures and temperatures. The object of research to substantiate the parameters of artificial creation of gas hydrates is biogas obtained during anaerobic thermophilic fermentation of organic waste at an existing experimental biogas plant. Mixed feed SK-8 with a humidity of 90-92 percent was used as an organic substrate of constant composition. The composition of biogas was studied using the Optima-7 Biogas gas analyzer. (Results and discussion) The article presents a process model and a technical appearance of an installation for producing gas motor fuel from the biogas of anaerobic digestion of organic waste of the agro-industrial complex. The hydrate formation time depends on the increase in the interfacial surface and the movement of gas bubbles relative to the liquid, which can be regulated by acting on the hydrate formation zone (shock wave, electromagnetic, mechanical, chemical, temperature). (Conclusions) The research results can be used in modeling processes in two-phase media during the formation of gas hydrates and the creation of installations for their production.

ENSURING QUALITATIVE-ACCURACY CHARACTERISTICS DURING RESTORING OF VEHICLE PARTS

One of the most common reasons for the failure of hydraulic drive systems for agricultural machinery is the working fluid leak in the contact points of the rubbing surfaces of hydraulic blocks. The application of composite coatings based on chromium on the contacting surfaces allows you to restore the defect in the shape of the part caused by wear, as well as reduce the friction coefficient at the contact points, which positively affects the wear resistance of the part. (Research purpose) The research purpose is in developing technologies for restoring parts of agricultural machinery with predetermined operational properties. (Materials and methods) A servo valve, widely used in various hydraulic drive systems, was used as an experimental sample. Its working surface was restored with a composite coating applied by electroplating to increase the wear resistance of the servo valve. (Results and discussion) Authors conducted a series of direct measurements under the same conditions. The article presents the de-pendence of the microhardness on the parameters of the electrolysis mode and the thickness of the applied coating using the method of least squares. The nature of changes in microhardness and residual stresses was evaluated to determine the quality of the coatings. The article presents the dependences of these indicators on various control parameters (current density, temperature, tool pressure). The equations of the regression of the main qualitative and accuracy characteristics of the parts were deter-mined using the apparatus of the theory of experimental planning. (Conclusions) The article presents the method for predicting coatings of a given quality, taking into ac-count the influence of the current density and the temperature of the electrolyte during electrolysis on the nature of the precipitation obtained. The influence of the tool pressure on the depth of deformation of the formed layers was estimated. This approach allows us to evaluate the nature of the stress distribution in the formed coating and the quality of the restored parts.

OPTIMIZATION OF THE REPAIR AND MAINTENANCE BASE OF THE AGRO-INDUSTRIAL COMPLEX

The repair industry in almost all countries has entered a critical period, characterized by the need to combine and use various strategies and technologies for maintenance and repair of new equipment, as well as equipment produced many years ago. (Research purpose) The research purpose is in analyzing the state of the repair and maintenance base of the agro-industrial complex and justifying the possibilities of its modernization using intelligent technologies. (Materials and methods) Authors used methods of generalizing data from various services of agro- industrial formations of individual regions, materials of scientific and technical literature and research developments, studied data on the practical use of modern resource-saving technologies by engineering services of the agro-industrial complex of the regions when carrying out repairs and service and technological services. (Results and discussion) The lack of information about the state of the repair and maintenance base makes it difficult to determine all the criteria associated with the transition of manufacturers to a contract of the entire life cycle. Obtaining information about the state of the repair and maintenance base of the agro-industrial complex is a very important stage that contributes to the modernization of this base and attracting not only the governments, but also agricultural machinery manufacturers to modernization. (Conclusions) The technological level of the enterprises of the repair and maintenance base of agriculture has significantly decreased in recent years, and this has affected the decline in technical readiness indicators, which confirms the need to conduct research and implement in practice the main measures related to the modernization of the specified repair and maintenance base.

OPERATIONAL ASSESSMENT OF THE LIMIT STATE OF TRACTOR UNITS WITH THE USE OF INDICATOR COUNTERS

In accordance with GOST 20793-2009, the tractor and its components are subjected to resource diagnostics before maintenance. The technical condition of the components of the tractor or machine should be checked with the use of control and diagnostic equipment. Currently, the criteria for the limit state are significantly outdated and require revision from the point of view of tightening modern requirements for operational and economic characteristics and reliability indicators. (Research purpose) The research purpose is in analyzing the state of the issue and the current regulatory documentation and making proposals for remote monitoring of the criteria for the limit states of individual components and aggregates. (Materials and methods) The article presents an analysis of scientific and technical documentation, State standards of the Russian Federation and scientific papers on the problems of minimizing technological risks, diagnostics and control suitability for determining the maximum technical condition, and staged studies on the possibility of monitoring the operation of individual components and units online. The article notes the need to adjust the criteria for the maximum technical condition in accordance with the new designs of resource-determining units, aggregates and existing technical regulations. (Results and discussion). The article presents the justification of the diagnostic process and identified contradictions in the design of tractors and existing scientific and technical documentation and standards, and proposed option of using meters-identifiers when upgrading tractors as a system of built-in online diagnostic tools. (Conclusions) Timely, automated monitoring of the technical condition of tractors, which is based on comparing data with the criteria of the limit condition, serves as a justification for the effective operation of equipment with built-in devices for diagnostics, which allows minimizing agrotechnological risks.

THE CONCEPT OF RECYCLING OF AGRICULTURAL MACHINERY AND THE GENERAL PRINCIPLES OF ITS IMPLEMENTATION

In a broad sense, the utilization of agricultural machinery is a set of technical, organizational, economic, legal, financial and environmental measures to ensure the effective utilization of agricultural machinery, its aggregates (compo-nents of the technical base) at the final stage of the life cycle in order to maximize involvement in economic turnover. (Research purpose) The research purpose is in analyzing the work of foreign and domestic authors related to the formation of a resource-saving, environmentally-oriented system for recycling equipment. (Materials and methods) The article presents diverse studies in various areas, in which various materials and methods were used. Authors used a large amount of data characterizing the possibilities of creating a system for recycling agricultural ma-chinery in the agro-industrial complex of Russia, based on the state of the agricul-tural machine-tractor fleet, its age characteristics and the ability of engineering enterprises to carry out this type of activity. The obtained information was processed using statistical analysis methods. (Results and condemnation) The developed con-cept determines the necessity of creating a specific (industry-specific) system for the disposal of agricultural machinery in the agro-industrial complex of Russia as a component of a unified system for the disposal of machinery. (Conclusions) The conducted research showed that Russia is significantly lagging behind foreign countries in solving the problem of recycling equipment, so the best option can be considered to be working out the recycling mechanism in the process of building a local (industry) recycling system at the regional level. This will allow us to work out the elements of the national system for the disposal of decommissioned equip-ment in a relatively short time with minimal expenditure of various kinds of resources. The article presents the amount of subsidies for the creation of a specific system for the disposal of agricultural machinery in Russia.

THE INFLUENCE OF THE COMPOSITION AND SIZE OF THE FRACTIONS OF THE COMPOSITE GRAVEL FILLER WITH AN EPOXY MATRIX ON ITS WEAR

The widespread use of polymer-based composite materials made it possible to replace expensive metal alloys, increase the strength indicators of structures and improve tribotechnical properties. Their use as protective coatings for structural elements operating in an abrasive environment has yielded good results in increasing wear resistance, which is especially important for parts of tillage tools. (Research purpose) The research purpose is in studying the influence of the composition and size of the fractions of the composite gravel filler with an epoxy matrix on its wear. (Materials and мethods) The article considers five composite materials with different compositions. The prototypes were hollow cylinders with dimensions that provide the contact area necessary for the passage of all processes of abrasive wear. The abrasive composition consisted of a mixture of sand and gravel with a fraction size of about 30-40 millimeters. (Results and discussion) The changes in the wear over time are directly proportional and this confirms the classical views on the wear process. The experiments was conducted on the installation of authors’ design. (Conclusions) The wear over time for experimental composites is the same and is expressed in a straight- line relationship; the maximum wear resistance is a composite in which gravel particles have a size of 2.25 millimeters with its content in the matrix of about 60 mass parts. At the same time, gravel with an effective diameter of 2.25 millimeters creates optimal conditions for self-organization of the wear process and provides a relatively low value of the friction coefficient.

CLASSIFICATION OF TWO-DISC COULTERS BY TECHNOLOGICAL AND DESIGN PARAMETERS

High-quality sowing of grain crops depends on the design of the working bodies of agricultural machines. Based on analytical studies, it was proposed to develop a new classification of individual structural elements of coulters and their technological parameters. (Research purpose) The research purpose is in improvement of the digital classification table of coulter signs, the structure and form of representation of which would allow easily complementing the signs characterizing the studied working body without changing its formation algorithm. (Materials and methods) The coulter can be considered as a system consisting of a combination of individual design and technological features that are closely related to each other. A two-disc coulter was analyzed according to the proposed classification, and a digital coding system was proposed. This classification allows us to include not only the known types of coulters, but also to predict new designs for the specified technologi-cal parameters. (Results and discussion) The features and properties of coulters in the matrix are located vertically and horizontally, respectively, and are considered in in-teraction, coulters of one class are associated with many features and properties of coulters of another class. This classification allows you to replace the existing large classifications with ordinary numbers, to conduct digital coding of any coulters of sowing machines. (Conclusions) The proposed classification allows us to apply digi-tal coding of the entire variety of features and properties of existing and new designs of two-disc coulters, to use computer technologies for searching, storing and pro-cessing information on them. The classification is used to select a rational design of the working body.

WEAR OF THE RIGHT KNIFE OF THE PSKU SPEED PLOW AND TECHNOLOGICAL MEASURES TO INCREASE ITS DURABILITY

The intensification of crop production has led to the creation of equipment for high-speed tillage. The high speed of plowing causes an increased intensity of wear of the working bodies of plows. The limit capacity of the vertical knife when processing loamy soils is about 30 hectares, after which the body must be subjected to repair (maintenance) operations. (Research purpose) The research purpose is in studying the wear of the right knives of the PSKU plow (geometry and location on the working surface), assessing the technical condition and develop measures to improve their durability. (Materials and methods) The right knife (plowshare) performs the function of a pruning element, its design corresponds to the design of the plowshare in the classic version, but with reduced dimensions. We carried out wear control in width and thickness on 14 parts. (Results and discussion) The knives after working 30 hectares are suitable for further use in width. The width of the solid layer deposited on the back side is about 7-8 millimeters, so additional surfacing of the abrasive-resistant alloy is necessary. The wear on the thickness of the knife cannot be the reason for its decommissioning, since the strength and rigidity are preserved, and the agrotechnical requirements for soil cultivation are not violated. (Conclusions) The residual width and thickness of the studied knives when plowing loam retain the normalized limits, which indicates the possibility of their further operation, but it is necessary to weld the cutting-blade part from the back with an abrasive- resistant alloy. The xiphoid wear is fused with an electrode that provides a roller hardness of about 50 HRC. A low level of wear rate of the part is achieved due to the hardness of the blade area 60 HRC.

FAILURES OF POLYMER PARTS OF AGRICULTURAL MACHINERY

Since the last century, polymer materials have been widely used in industry. They are increasingly being used in the construction of agricultural machinery. Simultaneously with the spread of polymer parts, there is a need to develop technologies for repairing agricultural machinery containing such parts. (Research purpose) The research purpose is in analyzing the failures of polymer parts of agricultural machinery and equipment. (Materials and methods) The article presents a study of cases of failures of polymer parts of agricultural machinery based on data received from the enterprise LLC "Rassvet" of the Rostov region, the production cooperative "Koelginskoe" of the Chelyabinsk region for 2019 and summary information from various suppliers of spare parts of agricultural machinery. (Results and discussion) The parts of the industrial water treatment filter, turbine water meters and the sprayer housing failed at LLC "Rassvet" during the period under review. In the production cooperative "Koelginskoe" the gear of the servo drive of the grain flow and the oil seal of the hydraulic cylinder of the tractor K-744 failed, and therefore it was necessary to replace the entire unit. It is unprofitable for dealers of agricultural machinery to supply parts in a single copy due to their low cost. (Conclusions) The nomenclature of polymer parts of agricultural machines that fail is quite diverse, and cases of their failures are not rare. In some cases, the replacement of these parts is impossible due to their absence from sale, and in other cases, it turns out to be unprofitable due to long delivery times or a large minimum order batch. In this regard, agricultural producers suffer significant losses, overpaying for a whole node instead of replacing one part.

KINEMATICS OF THE DISTRIBUTION MECHANISM OF THE HYUNDAI ENGINE WITH ADJUSTABLE VALVE OPERATING TIME

Increasing the efficiency of modern internal combustion engines is going in the direction of optimizing the gas distribution phases in order to adjust them to the operating conditions of motor vehicles. Hyundai has announced the development of the first production engine with continuously variable valve operation time – Continuously Variable Valve Duration. (Research purpose) The research purpose is in conducting a kinematic analysis of the gas distribution mechanism with an adjustable valve operating time, identifying the theoretical possibilities of this mechanism in comparison with the information provided in the prospects. (Materials and methods) The methods of kinematic analysis of lever mechanisms were used in the work. (Results and discussion) The analysis of the design of the gas distribution mechanism with an adjustable valve operating time made it possible to choose a suitable structural scheme that is equivalent to the original mechanism. The article presents the most effective method of kinematic analysis of this mechanism and developed on its basis a program for calculating the angles of rotation of the cam and the shaft of the gas distribution mechanism. (Conclusions) An engine with a valve operating time control system allows you to more effectively adjust the cylinder filling depending on the operating conditions due to the variable phase of rotation of the camshaft. The valve timing control system offered by Hyundai should only work with the valve timing control mechanism, since when the cam rotation speed changes, it starts working in the wrong phase that should be at a given time. With a slow rotation of the cam, it lags behind in phase from the shaft of the gas distribution mechanism, and with a fast rotation of the cam, on the contrary, the phase advance of the shaft of the gas distribution mechanism occurs.