No 6 (2019)

Articles

Titchenko Prospects for the use of dry carbamide in diesel exhaust gas aftertreatment systems

Kaminskij V.N., Nadarejshvili G.G., Panchishnyj V.I., Zagredinov R.M., Titchenko A.Y.

Abstract

Improvement of diesel exhaust gas aftertreatment systems is one of the most urgent methods of technical competition with the electric transmission, which has been developing rapidly in recent times. The search for the most optimal technical solutions will reduce the environmental load when using diesel engines. This article discusses the prospects for the use of dry carbamide in neutralization systems of diesel engines. A dry carbamide system is free from a significant drawback of the widely used SCR Nitrogen Oxide Reduction System. Such systems are not resistant to low temperatures below -11 °C and require heating, which entails significant energy costs and design complexity. The methods for the direct use of ammonia for the reduction of nitrogen oxides are known. Amminex Company uses ammonia bound in the form of salts. A design that already has practical application is considered. The buses used blocks, generating the required amount of ammonia. One set is enough to work for one two days. Blocks are replaced by infrastructure. The design is simple enough and undoubtedly efficient. There are also patents describing devices based on direct thermolysis of carbomide. In this case, it is possible to create a compact design that requires practical application. The main reactions occurring upon receipt of ammonia from a solution (urea), ammonia salts, and dry carbamide are presented. The features of thermolysis at various heating rates and temperature levels are considered. The paper analyzes the reactions proceeding in three design options. An energy analysis has been carried out and a conclusion has been drawn on the advantage of direct thermolysis of carbamide. A design variant of the exhaust gas aftertreatment system for diesel engines using direct thermolysis is proposed. Based on the results of a wide analysis, it was concluded that the structures constructed on the basis of direct thermolysis of dry solid carbamide are promising.
Tractors and Agricultural Machinery. 2019;(6):3-14
pages 3-14 views

Drift of mechanical characteristics of Common Rail fuel lines during operating time

Sveshchinskij V.O.

Abstract

During the operation of steel pipelines, there is a change, drift, in the characteristics of the materials from which they are made. In the field of technological pipelines and oil and gas complex pipelines, an extensive literature is devoted to this issue, including both scientific publications and regulatory state and industry documents. Changes in the material characteristics of high pressure fuel lines of internal combustion engines did not attract the attention of specialists. Fuel lines were an important component of engines, but at that injection pressure level, materials and technologies, which determine, inter alia, the cost of a component in the total cost of the engine, they remained outside the area of special attention. The development in Russia of its own production of Common Rail systems makes it necessary to study the behavior of parts under conditions of prolonged loading with an internal hydraulic pressure of 1600 kg/cm2 and higher. The drift of the characteristics of the materials of the high pressure fuel lines can be of great importance, in terms of the reliability of the fuel system and the whole engine. For the first time, studies were carried out of the mechanical characteristics of seamless steel pipes at various operating times on a non-motorized test bench under loading with an internal hydraulic pressure of 1600 kg/cm2 with a pulsation frequency of 45-55 Hz. It has been established that during running hours, the hardness in the cross sections of the fuel lines increases. The standard deviation of hardness values also increases, i.e. the spread of values is present. The nature of the change in the tensile strength and yield strength with an operating time of more than 1100 hours requires additional research. It is concluded that it is necessary to test a larger number of samples on the engine to find out the limiting values of the mechanical characteristics of the material.
Tractors and Agricultural Machinery. 2019;(6):15-20
pages 15-20 views

Method of selection of optimal damping coefficients for torsional vibration dampers of crankshafts of automobile and tractor engines

Gots A.N.

Abstract

We have analyzed of free oscillations of the reduced torsional system of the crankshaft of a six-cylinder piston engine with the rubber or liquid damper. When we installed the torsional vibration damper on the crankshaft, than it changes the frequency of free oscillations. For the rubber damper it is changing the freguency of free oscillations while we is added mass of the body of the damper and the coefficient of rigidity of the rubber layer and the moment of inertia of the flywheel, which is added to the moment of inertia .the first mass (the toe of the crankshaft). For liquid torsional vibration damper, the flywheel which has no direct connection with the toe of the crankshaft, the calculation of free oscillations is half the moment of inertia of the flywheel, fluid damper end to the moment of inertia of the sock. We consider the procedure for selecting the optimal damping coefficients of dampers, and, namely, the moments of inertia of the flywheel damper and damping coefficients. When selecting the amplitudes of the free oscillations of the mass of the damper flywheel and the crankshaft wear (or damper body) in a complex form and substituting derivatives of these quantities in the differential equations of free oscillations, the functions that can be taken as optimization parameters are obtained. In this case, the amplitude of the torsional vibrations of the crankshaft wear is reduced as much as possible with the optimal damping or the maximum of the energy dissipated in the damper. For internal friction dampers, a rubber layer stiffness coefficient is added in addition to the specified parameters. It is shown that these selected parameters also affect the circular frequency of free oscillations, so their selection should be carried out taking into account this circumstance.
Tractors and Agricultural Machinery. 2019;(6):21-27
pages 21-27 views

Modern test benches for dynamic tests of tractor tires

Vlas'evnina E.A., Osipov O.I.

Abstract

For testing tractor tires and their wear, special laboratory stands with imitation of real tire operating conditions are used. They provide the definition of such characteristics of the tire as the possibility of continuous movement at maximum speed, the perception of forces during curvilinear movement, dynamic radius, tire rolling resistance, degree of tire heating, etc. Such test benches allow to evaluate the reliability of the tires and to identify the possibility of increasing their life cycle. The most common test benches include a fixed platform, a running drum, hydraulic cylinders, clamping devices, an electric drum drive, tire rotation mechanisms, a personal computer and a control panel. One of the drawbacks of such test benches is the presence of high losses to overcome efforts in the mechanisms of rotation of tires. Therefore, the urgent issue is to find solutions to improve energy efficiency and reliability of tractor tire tests. The article analyzes test benches of foreign and domestic manufacturers for dynamic tire tests. Their technical characteristics, functional indicators and overall dimensions are considered. Considerable attention is paid to the shortcomings of each of the test benches. A modernized version of the test bench is proposed, in which the disadvantages of analogues are taken into account and eliminated. The design of such a test bench allows testing tires, simulating their interaction with an uneven road surface, as well as reducing energy consumption and increasing the reliability of tire tests. A kinematic diagram of the test bench and a functional diagram of the power part of the electric drive of the test bench are proposed. Based on the technical data of the test benches and their capabilities, a comparative table is given, as well as conclusions about the feasibility of using more energy-efficient drives for such test benches is proven.
Tractors and Agricultural Machinery. 2019;(6):28-35
pages 28-35 views

Development of a method for obtaining a section of reduced stiffness on the elastic characteristic of a vehicle tire

Ryabov I.M., Pozdeev A.V., Erontaev V.V., ZHdamirova E.V.

Abstract

This article is devoted to the development of a method for obtaining a section of reduced stiffness on the elastic characteristic of a pneumatic tire of a wheeled vehicle. A way is proposed to reduce the radial stiffness of a tire by obtaining a section with reduced stiffness on the elastic characteristic of pneumatic tires, which, unlike the known ways, can significantly reduce the radial stiffness of a pneumatic tire with-out increasing its static radial deformation and rolling losses. The essence of the method for obtaining a section with reduced stiffness is to reduce the air pressure in the pneumatic tire while increasing its radial deformation using original internal devices located inside the tire. An algorithm has been developed that includes four stages; the elastic characteristic of the pneumatic tire 8.40-15 with a section with reduced rigidity by 4 times is obtained. This ensures a decrease in the natural frequency of vertical oscillations of the sprung mass on the bus by almost 2 times from 3,5 to 1,8 Hz. On the basis of the developed method, the dependences of the length of the reduced stiffness section and the force change in this section on the natural frequency of the sprung masses on the tire realized in this section are determined. For the tire 8.40-15, the dependence of the change in force in the section with a given reduced stiffness on its length was determined, which showed that with increasing length of this section there is a progressive change in the load on the tire in the same section. In addition, the dependences of the pressure change in the tire on its radial deformation in areas of reduced stiffness were obtained for various given frequencies of natural oscillations of the mass of the load on the tire. Structural diagrams of vehicle wheels are presented, in which the tire contains internal structural elements that implement the proposed method for reducing the radial stiffness of a vehicle tire and, in addition, possessing internal hydraulic or air damping of the vertical vibrations of the wheel.
Tractors and Agricultural Machinery. 2019;(6):36-47
pages 36-47 views

Problems of operation of small-capacity automobile trailers in various fields of agriculture

Godzhaev Z.A., Balakina E.V., Korolyash V.A.

Abstract

The article discusses the prospects for the development and use of SRT (small-tonnage road trains) with a controlled coupling device developed and confirmed by the application (2018137360) of Volgograd State Technical University and Federal Scientific Agroengineering Center VIM. Small-tonnage road trains in terms of noise, ecology and fuel consumption are much superior to main-line trains when used in megacities, as well as in difficult road conditions. An increase in the number of small enterprises in recent years, including enterprises engaged in agriculture, maintenance of greenhouses, retail outlets, hunting and the provision of services in this area, increases the need for small trailers used in conjunction with automobiles. A controlled hitch allows eliminating «wobble», as well as providing the ability to steer in reverse. In various sectors of the national economic activity, SRT has advantages in servicing small enterprises, cooperatives, greenhouses and agricultural enterprises. Among other things, it does not require retraining of drivers and a quick payback time of less than 3 months. SRT is a universal type of transport. This is achieved by the development of various trailed platforms necessary to carry out various types of work. It can also be a trailed mini-plant for processing and recycling waste from agricultural enterprises (cowsheds, poultry farms, greenhouses, etc.). A possible option is a mini workshop, a kitchen, a mobile first-aid post for servicing workers engaged in sowing, cleaning, etc. In connection with new trends in the development of road transport, it is advisable to develop SRTs in an automated control option, through GLONASS using the Skif and Scout systems, as well as the trailer’s ability to independently move in geopolation mode for various tasks. With all the obvious advantages, there are negative phenomena that require thorough study and the possibility of eliminating these phenomena. Studies require the movement of a SRT with a high trailer when exposed to large or cyclic lateral forces, as well as the exclusion of wobble when moving along a longitudinal track and when overtaking.
Tractors and Agricultural Machinery. 2019;(6):48-53
pages 48-53 views

Ensuring the operability and fault tolerance of machinery by redundancy of replaceable elements

Eltoshkina E.V., Buraev M.K., Bodyakina T.V.

Abstract

The main task in mechanical engineering is to ensure the efficiency of the machine-tractor fleet. Technical operation of machines requires new organizational and technological approaches to maintaining it in working condition in zonal conditions of use. Since every hour of downtime of this expensive equipment leads to high costs, one of the important tasks will be to reduce the downtime of machines for maintenance and repair. Development of import substitution programs and food security of regions and regions of the country is an important area for scientific and public organizations to solve the tasks set by the government of the Russian Federation. In this regard, the study of foreign technologies and the introduction of their own in the production of machinery and agricultural products. The aim of the study is a mathematical description and justification of fault tolerance of machines to ensure performance at a given level.In the article deals with the issues of ensuring the efficiency of technical systems (machinery and equipment) and planning the number of spare elements during technical service. It is rather simple to establish the cycles of repair time of machines and technology, if the variables of the technical state determining the operability of the machines during operation are deterministic. In practice, in most cases, the performance is determined by the stochastic nature of the influencing factors, forcing to take into account the technical and mathematical methods for their description. In a situation where the recovery time of the failed element is an order of magnitude shorter than the uptime, or the restoration is reduced to replacing the element with a backup, it is natural to accept the model of an instantly restored element.
Tractors and Agricultural Machinery. 2019;(6):54-57
pages 54-57 views

Efficiency of cleaning and the life cycle of the modernized filter for rough cleaning of diesel fuel

Halturin D.V., Lysunec A.V.

Abstract

The paper considers the problem of the reliability of the fuel equipment of tractor diesel engines at low temperatures. The main problem of the operation of such engines is the deterioration of fuel pumpability through the fuel lines, waxing and clogging of fine filters. The authors propose a new design of the coarse filter (CF), where the filter element is a filter tape made of nonwoven needle-punched material with variable compression, which has increased filtration efficiency with the possibility of simultaneous heating of the fuel. The advantage of the proposed changes is the use of a standard coarse filter housing. Performance tests are presented. According to the results of operational tests of the upgraded coarse filter, it was found that, unlike the standard element, the mass concentration of contaminants is reduced by about half, and the probability of dropping out particles larger than 30 microns is 90 %. The particle size distribution curves of contaminants after a standard and upgraded filter and a resource characteristic are built. The results of comparative operational tests of filters for pollution are presented. The pressure drop across the filter at the onset of maintenance is estimated, and an increase in scheduled filter replacement is suggested. The degree of compression of the filtering material was determined to exclude the appearance of particles larger than 35 μm after the CF.
Tractors and Agricultural Machinery. 2019;(6):58-64
pages 58-64 views

Implementation of nature-like technologies in the development of new working bodies for tillage in arid conditions

Parhomenko G.G.

Abstract

In accordance with nature-friendly technologies, in arid conditions, the accumulation of moisture inside the soil layer is necessary. With a significant difference in the soil temperature of neighboring layers and a decrease in the thickness of the treated layer, moisture is available locally for the plant root system, without dissipation over the entire arable horizon. Purpose: improving the design of the working bodies for tillage, taking into account the zonal-natural conditions of their application. A significant difference in thermophysical characteristics can be achieved with a different structure of neighboring soil layers. The thickness of the treated layer decreases due to the differentiation of the layers during layer-by-layer subsurface tillage and a decrease in the depth of cultivation by each element of the working body. Finding the optimal shape and parameters of the cultivator, chisel and rack of paraplow type of the working body will provide the necessary formation structure to control the process of moisture accumulation in the soil, provided that the agrotechnical indicators are of high quality at a minimum cost. To reduce the resistance to crumbling of the reservoir, it is advisable to present the cultivator in the form of a curve with the property of minimum, the ellipse. The solution to the problem of transforming a paraplow-type strut from a broken line into a curved line is the differential brachistochrone equation of the first order. The parameters of the chisel for the implementation of the technological process with the least energy consumption are selected due to the rational ratio of the cross-sectional area of the treated formation. It is necessary to spend the optimal amount of energy when compressing the soil formation on the bit, creating the necessary and sufficient stress (not more than 3 kPa) to ensure high-quality crumbling of the formation without unloading in front of the working body. It is advisable to apply the principle of the golden ratio, dividing the depth of cultivation into a harmonic proportion of 62 % and 38 %. The depth of the cultivator will be 13-15 cm while the depth of cultivation is 34-39 cm.
Tractors and Agricultural Machinery. 2019;(6):65-73
pages 65-73 views

The effect of overlapping adjacent passages of the unit on the uniformity of the application of mineral fertilizers

Sedashkin A.N., Kostrigin A.A., Milyushina E.A.

Abstract

The article presents some results of studies on the effect of overlapping widths on the uniform distribution of fertilizers on adjacent passages of an aggregate conducted at the N.P.Ogarev Mordovia State University. Recommendations are offered on reducing the ratio between the working width and the spreading width during centrifugal apparatus operation. Observations showed that spreaders with centrifugal type working elements distribute fertilizers unevenly across the working width. Most of them fall in the middle, and towards the edges their number decreases. To achieve a more uniform application, they are usually scattered with overlap. The studies are conducted to determine the effect of overlap on the uniform distribution of mineral fertilizers. To assess the uniformity of the surface distribution of mineral fertilizers and lime by the experimental setup along the working width and in the direction of travel, the fertilizers were collected in baking sheets of 0,5×0,5×0,1 m in size. The baking sheets were placed on an even area tightly to each other in three rows with row spacing of 5 m. During the experiments, the non-uniformity of fertilizer application at a machine grip width of 10 m with an overlap of 2 m was higher than the agrotechnical permissible values - 25 %. Studies have shown that it is possible to increase the uniformity of application while reducing the width of the aggregate to 8 m, while the overlap should be at least 4 m. Studies have shown that it is possible to increase the uniformity of application while reducing the width of the aggregate to 8 m, while the overlap should be at least 4 m. At the same time, the problem of ensuring accurate driving of fertilizer applicators is even more acute with an increase in the working width of modern high-performance equipment. Obviously, in this case, in the absence of special stands for the operational tuning of machinery, it is very difficult to correctly adjust them. Therefore, each time you change the type of fertilizer and doses you need to check the position of the regulator with the recommended operating instructions. The working width of the grip depends on this, and, consequently, the distance between adjacent passages of the unit is dependent. The quality of centrifugal machines, in addition, depends on the quality of the applied mineral fertilizers (range of sizes and shapes of granules, flow-ability), the state of the field topography, the evenness of the soil, wind speed, the qualification of the machine operator and its good faith (strict adherence to a given speed), operating speed and etc. Obviously, in order to introduce mineral fertilizers with permissible unevenness (permissible coefficient of variation for nitrogen fertilizers ±10 %, for potash and phosphorus ±20 %), centrifugal working bodies must strictly comply with the requirements of the work execution regulations.
Tractors and Agricultural Machinery. 2019;(6):74-78
pages 74-78 views

Improving the competitiveness of mechanical engineering

Kushnarev L.I., Aleshin V.F.

Abstract

The low level of competitiveness of Russian machinery and equipment is due, first of all, to an insufficient level of workmanship and reliability indicators. In terms of technical characteristics, the level of resource saving, the implementation of modern technological methods and methods for the manufacturing of products, works and services, many models of modern machinery are not inferior, and often surpass foreign analogues. But the low level of reliability indicators and, above all, the reliability of machines in the end significantly reduce the efficiency of its use in real production and economic conditions of consumers of equipment. The work is aimed at searching and substantiating directions for improving the quality of manufacturing and reliability indicators of domestic machinery and equipment based on the creation of proprietary production and technological systems and complexes and the introduction of a proprietary method of technical service. Improving the quality of Russian equipment on an innovative organizational and technological basis will ensure the necessary technological breakthrough in mechanical engineering with the minimum needs of production and technical resources in a short time. Studies indicate the need to reorganize engineering enterprises into large firms, branded production and technological systems and complexes that can provide a sharp and significant increase in the quality of equipment to the level of the best world analogues. The organization of large engineering companies allows solving the quality problems of machinery and equipment at all the main stages of their life cycle: design, construction, production, operation and disposal. At the same time, the efficiency of resolving emerging issues is significantly increased, since all structural divisions of the company are managed from a single center, whose strategic goal is to comprehensively improve the quality of engineering products. A quick and significant increase in the competitiveness of domestic machinery and equipment based on an increase in their manufacturing quality and reliability indicators is possible only with the introduction of their proprietary technical service. The company service system will allow establishing and excluding the causes of operational failures of machinery.
Tractors and Agricultural Machinery. 2019;(6):79-85
pages 79-85 views

Determination of the effect on the energy intensity of granulation of the radii of the working bodies of the press granulator

Polishchuk V.Y., Panov E.I., Vasilevskaya S.P.

Abstract

Previously unknown properties of the pressing mechanism of the press granulator with one largediameter pressing roller were revealed. Using the method of a computational experiment taking into account a previously conducted experimental study of the granulation of a semifinished product of plant origin, the energy intensity of the granulation process is determined using a mathematical model of the stress state of the semifinished product pressed in the working space of a press granulator. The dependences of the geometric parameters of the working space of the pressing mechanism are determined. Using the methods of plasticity theory, the forces of useful resistance to the motion of the annular matrix are determined. Based on them, the power of useful resistance forces is determined. Based on the calculation of the stress state of the pressed semifinished product in the pressing mechanism, the boundaries of the zone of extrusion of the semifinished product into the die plate are determined. Based on the calculation of the mass flow rate of the semifinished product at the entrance to the extrusion zone and at the exit from it, the productivity of the pressing mechanism on the unit width of the working bodies is calculated. The energy intensity of the granulation process is determined by the ratio of the power of the forces of useful resistance to the productivity of the pressing mechanism on the unit width of the working bodies. In a computational experiment, a comparison was made of the energy intensity of the pressing mechanism of the PGM-05 press granulator and the design of the pressing mechanism with the working tool radii increased proportionally by 20 %. It is shown that an increase in the radii of the matrix and roller of the press granulator by 20 % increases productivity and reduces the energy consumption of granulation. If the energy intensity of the process is the same, then productivity increases by 60...89 %. With an increase in energy intensity, an increase in productivity decreases. If the productivity is the same, then the energy intensity is reduced by 31...38 %. With increasing productivity, the drop in energy intensity decreases. Thus, we can conclude that it is advisable to increase the radii of the working bodies of the PGM-05 press granulator by 20 %.
Tractors and Agricultural Machinery. 2019;(6):86-92
pages 86-92 views

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