Vol 92, No 3 (2025)

One of the main problems of the present time is environmental pollution with harmful substances formed during the combustion of traditional hydrocarbon fuels in internal combustion engines that provide moving of vehicles.

This is felt especially acutely in large cities.

The solution is the transition to hybrid power units and electric vehicles, including the use of hydrogen as the most environmentally friendly fuel.

Therefore, consideration of the totality of the impact on the environment of both the replacement of cars with electric vehicles and the consequences of electricity generation is a relevant task.

But the environmental effect of using electricity in vehicles is usually considered only for areas of transport operation. However, the generation of electricity at power plants goes with air pollution.

The use of electric power in vehicles is possible, firstly, by means of charging traction batteries from external power grids transmitting electricity from power plants and, secondly, by means of on-board electricity generation using fuel cells, in which hydrogen serves as fuel, while the by-product is water. However, the electricity generation mainly occurs at thermal power plants by means of burning hydrocarbon fuel such as natural gas and coal, which leads to formation of harmful substances and their subsequent emission into the atmosphere. When generating electricity at nuclear power plants, a large amount of water vapor is released into the atmosphere, which has three times greater greenhouse effect compared to carbon dioxide. The operation of power plants with renewable energy sources (solar, wind) significantly depends on natural conditions, hydroelectric power plants also play an auxiliary role. The use of hybrid motor units allows the use of hydrogen in heat engines, the combustion products of which are water and nitrogen oxide. But there is no free hydrogen in nature, and its production is ensured mainly by steam conversion of methane, which goes with the formation of harmful substances and "greenhouse" gases. The use of liquefied hydrogen and liquid hydrogen carriers in transport also requires consuming of electricity, which leads to air pollution.

The value of this review lies in the evaluation of the cumulative impact of the technical solution to switch to the use of electric transport instead of motor vehicles on the environment.

Dynamics of scientific and technological progress are such that the modern world economy features excessively high rates of mineral extraction, which outpace the processes of natural renewal. Depletion affects on geopolitical conditions. Nowadays, the arctic area is one of a few areas in the world that contain huge mineral resources. A number of states lay claims on transpolar territories. The true interest to exploration the Arctic is based on set of strategic and economic grounds. Protection and ensuring national interests of Russia is provided by the Presidential Decree No. 645 “On strategy of development of the Arctic Zone of the Russian Federation and ensuring national security for the period up to 2035” dated October 26, 2020. Main feature of transarctic regions is negative air temperature. The latter negatively influences on working processes of piston engines, processes of phase state change of liquid fuel at air-fuel mix preparation, hinders working body homogenization and successful start. Therefore, heat preparation is needed. The existent methods of heat preparation of on-ground vehicles engines have unreasonable high energy and labor consumption. The modern science proposes new technology in solving the issues of heat preparation based on accumulation, storage and deploying heat energy produced by an engine during application.

The purpose of this review is to provide a comprehensive presentation of new solutions in field of heat preparation of engines, as well as solutions aimed at increasing the energy efficiency and adaptability of ground vehicles for use in Arctic conditions.

The described features of a heat accumulator present fundamental knowledge and give the direction to new

The induction-type phase transition heat accumulator, related to the group of highly efficient buffer systems for heat storage and deployment within the heat preparation, is noteworthy for design engineers, developers of basic internal combustion engines aimed to cold climate conditions with negative temperatures.

During operation, parts of the main components and subsystems of tractors are under dynamic loads. Parts of drivetrain and suspension are subject to especially intense dynamic loads. Reducing the level of dynamic loading of parts of drivetrain and suspension is ensured through the use of elastic and damping elements in designs of the machines. In this case, it is necessary to know how different types of damping affect the reduction of the load of parts under cyclic loads and which methods for determining the damping parameters of materials and structural elements have been proposed to date. The development of active damping devices, the elastic-dissipative properties of which adaptively change depending on the nature of dynamic influences is a relevant technical task; in accordance with this, the paper provides a description of the technical solution of such an adaptive damper proposed by the authors. The study was carried out by a calculation method based on the basic principles of the mechanics of materials and the theory of vibrations. Based on the analysis, recommendations were made for the selection of dampers for use in tractor suspensions, and a technical solution for an elastic damping device was proposed. The practical value of the study lies in the possibility of using the proposed recommendations for choosing the designs and characteristics of elastic damping devices for drivetrain and suspension of tracked tractors.

BACKGROUND: High torsional vibrations can lead to crankshaft failure. To reduce them, a damper is installed on the front crankshaft flange of high-powered inline diesel engines. The performance of torsional vibration dampers depends both on the damper design and the engine operating conditions. For a comprehensive assessment of damping performance, vibration amplitude of the crankshaft front flange is monitored. Thermal profiling of liquid dampers allows to determine their performance and characterize the changes in their thermal state based on temperature changes of the engine’s working fluid.

AIM: To study the damper thermal state and its influence on the torsional vibration damping performance.

METHODS: This study used experimental methods, conducted on an eight-cylinder automobile diesel engine. The value of the crankshaft twist angle was determined during the operation of the diesel engine by the external speed characteristic by torsiography on a special test bench. The thermal condition of the dampers was assessed by thermometry using special thermocouples, the measurement was carried out at the rated operating mode of the engine.

RESULTS: Thermal profiling of torsional vibration dampers was conducted. The authors determined the relationship between the crankshaft torsion angle, oil and damper temperature, and the warm-up time at 2,400 rpm.

CONCLUSION: The damper thermal state depends on the oil temperature in the engine pan and does not depend on the location of the measuring points on the housing. There are minor changes of the crankshaft twist angle when operating for 1 hour at 2,400 rpm.

The paper considers relevance of the issue of development of all sectors of the national economy, including such an important industry as agriculture. The development of the agricultural industry is associated in some cases with some of its specific features, which involve the necessity (sometimes historically developed) to have autonomous and remote objects of agricultural production. At the same time, production facilities and housing of service specialists are forced to be located at some distance from the sources of central (or main) electricity and heat supply.

To achieve the stated objective of this study, it is necessary to estimate the building's (consumer's) heat loss, which will be equal to the heat required for its heating. This required analyzing the heat balance data for the planned engine-generator system and the possibility of recovering secondary heat from the engine-generator in the exhaust gas, coolant, and oil recovery system, taking into account its simultaneous generation of electrical energy.

Based on the experimental heat balance data presented in the technical literature, it was found that the value generated from secondary heat in the engine-generator recovery system depends on the amount of electrical energy generated for the same consumer.

Based on the analysis, specific conclusions are made for the implementation of cogeneration plants at various facilities, both for investors and for manufacturers of cogeneration plants based on internal combustion engines.

BACKGROUND: This paper discusses the issues of increasing the dimensional accuracy of products obtained using additive technologies. As a production method, printing with fused polymer filament through an extruder (the FFF printing technology) is considered. The main problem in the production of products using this method is the lack of a systematic understanding in terms of assignment of the process modes that ensure the required accuracy and surface quality of the resulting products. This paper proposes the approach that makes it possible to develop technological recommendations to assign printing modes that ensure the stable obtaining of the required output process parameters.

AIM: Development of methodological approach to assignment of technological modes of printing with fused polymer filament, ensuring stable values of required parameters of dimensional accuracy and quality of surface layer of products.

METHODS: The study focused on the dimensional accuracy and surface quality of printed parts. Printers that print parts using an extruder nozzle served as the primary process equipment. The primary objective of the study was to substantiate a direction for improving the accuracy and quality of the parts. The study explored ways to improve the accuracy and surface quality of the parts using the analytic hierarchy process, which allows for the evaluation of options based on their significance. The final objective of the study was to confirm the feasibility of using vibration compensation to improve the accuracy and quality of the parts. The vibrations of the printer elements were measured using an accelerometer. The surface quality of the parts was assessed using a profilograph, and their dimensions were measured using a micrometer.

RESULTS: As a result of the calculation of the comparison coefficients in the analysis of the directions of increase in dimensional accuracy and print quality of the molten polymer thread, it was found that the best combination of criteria has an option that is associated with the analysis and reduction of vibrations during printer operation. The calculation was made based on the analysis of the experience of implementing the solutions under consideration in world practice. As a result of the analysis of vibrations that occur under various technological conditions, resonance conditions were revealed. An application firmware has been developed that allows you to configure the printer drive with the ability to eliminate resonances. As a result of studies of the accuracy and quality of the surface of products obtained on the basis of eliminating resonance phenomena and without it, it was found that the first option can significantly improve the output parameters of the process. As a prospect for further research, it is advisable to carry out a theoretical generalization of the results obtained in order to extend the proposed approach to printers of other designs, thereby making it more universal.

CONCLUSION: Studies have shown that the use of a methodological approach, which consists in identifying and eliminating resonant phenomena, makes it possible to increase the dimensional accuracy and surface quality of products obtained using additive technologies.

BACKGROUND: The most labor- and cost-intensive process in flax production is harvesting, which, depending on the technology used, takes 65–80% of labor costs, 55–75% of monetary costs and up to 40% of energy costs. Swath harvesting includes fiber flax pulling with a flax puller and simultaneous fiber flax retting in bands on the field. The agri-cycles of the technological process of fiber flax pulling per fiber are very compressed, up to 10–14 days for plants of green, early yellow ripeness, therefore, the quality of the fiber and the cost of the final product will depend on processing capacity of a puller. Pullers are specific machines, and are used only in fiber flax cultivation, therefore, the task of improving the technological process of pulling at swath harvesting of fiber flax is relevant, and the development of productive inexpensive pullers will improve the quality and economic performance of the process.

AIM: Improvement of the technological process of pulling at swath harvesting of flax by means of applying a new patentable technical solution.

METHODS: The object of the study was domestic and imported machines developed by scientific, educational, and production organizations for the threshing of long-staple flax during separate harvesting. A patent search and comparative analysis of existing machines and units were conducted. The study was based on data from online resources, information materials from Russian scientific, educational, and industrial organizations, and product catalogs from the main manufacturers of shearing machines for the period from 04.2023 to 04.2024. The selection of data was based on statistical data from Rosstat and the Ministry of Agriculture of the Russian Federation on the availability and use of machines for flax threshing during the reporting period. The advantages and disadvantages of the machine designs and their components were noted. Based on the obtained data, the technological process of flax threshing was improved, and the economic feasibility of the technical solution was assessed.

RESULTS: A study of the state of the issue of fiber flax pulling at two-phase harvesting, patent search and analysis of existing machines and units revealed that the main disadvantage is low processing capacity, as well as reliability at high production cost, which directly affects the technological process of pulling. The use of system analysis and economic justification made it possible to solve the task by creating a high-tech trailed machine for flax pulling.

CONCLUSION: As a result of the technical solutions adopted to improve the technological process of flax pulling at swath harvesting, a trailed fiber flax puller has been developed, which allows improving the quality of the technological process, as well as reducing the cost of the final product.

BACKGROUND: Applying organic fertilizers is an important condition for ensuring stable yields. The preparation and use of traditional types of organic fertilizers requires significant costs. Crushing and embedding of plant residues in the soil is a promising agrotechnical technique, therefore, it is necessary to modernize the straw grinder of a combine harvester for optimal mechanical action.

AIM: assessment of the energy consumption of the flattening process in conjunction with straw crushing.

METHODS: The object of the experimental study is the straw of grain crops and the process of various types of mechanical impact. The research was carried out on a developed laboratory installation that allows changing the number of cycles and the values of forces on the material under study in order to determine the maximum compaction at a certain straw flattening force and the energy intensity of this process.

RESULTS: It was found that with an increase in the number of subsequent loads, the degree of compression of the straw increases, but for use in a combine harvester, a single load is sufficient for the degree of flattening of the straw to reach 70%. It is worth noting that flattening dry straw does not require a very large effort, which means that the energy consumption for the flattening mechanism will be small — about 5 joules.

CONCLUSION: Accounting for energy consumption for flattening straw can be used in the design of special devices and devices.