Vol 92, No 1 (2025)

BACKGROUND: Agricultural production is a source of environmental pollution, therefore, solving the problem of reducing harmful emissions from diesel exhaust gases used in agriculture is important and relevant. Contrary to all forecasts, the use of environmentally friendly engines capable of competing with piston engines is limited in agricultural production. The study is aimed at solving one of the key problems of the present time — reducing the environmental impact from harmful emissions of diesel engines by means of changing the compression ratio.

AIM: Search for ways to reduce the environmental impact of diesel engines by means of changing the compression ratio.

METHODS: The experimental data were obtained during bench tests of the 4ChN 15/18 diesel engine according to the GOST 14846-2020. The test methods were in accordance with the GOST 10448-2014. According to the test program, diesel exhaust gases were selected, their composition and dispersion of solid particles were analyzed at compression ratios ε = 13.5...14.5 ...15.5 and the load curve at 1900 rpm.

RESULTS: It was found that an increase in the compression ratio from 13.5 to 15.5 led to a decrease in emissions of solid particles (SP), hydrocarbons (C_xH_y) and carbon monoxide (CO) with exhaust gases, however, emissions of nitrogen oxides (NO_x) increased through the entire load curve from P_e = 0 MPa to P_e = 1.24 MPa at 1900 rpm,. With a decrease of ε to 13.5, the environmental impact decreased by 1.15 times.

CONCLUSION: The compression ratio can be considered as an adjustable parameter when solving problems of reducing emissions of nitrogen oxides from exhaust gases and has little effect on changes in SP and CO emissions. When the compression ratio is reduced from 14.5 to 13.5, the environmental impact is reduced by 1.15 times. To obtain the best results, it is recommended to use complex methods, for example, simultaneous changes of the compression ratio and catalytic neutralization.

BACKGROUND: As the crop production is continuously being improved in the modern life support system of mankind with qualitative and quantitative yield, it is necessary to find a balance in the metal intensity of agricultural processes, since this undoubtedly has an important overall economic significance because obtaining stable and high-quality yield is necessary in the agricultural production system. A special place in this system is taken by basic tillage, both with and without seam turnover. To ensure the workflow of basic tillage for sowing, a new working body for basic non-fallow tillage was developed at the Donskoy Agrarian Scientific Center, in the structural division of SKNIIMESKh, Zernograd. The task is to conduct a comparative analysis of operation of the new working body with serial ones in preparing the soil for sowing.

AIM: Determination of the parameters of a deep tiller for anti-erosion tillage.

METHODS: The deep tiller, developed in the department of mechanization of crop production of the Donskoy Agrarian Scientific Center, carries out soil tillage with undercutting of the furrow along the width of the machine, performing non-continuous tilling by working bodies, with appropriate arrangement in the transverse direction. Morphological and functional analysis methods, as well as statistical extrapolation methods implemented in the Microsoft Excel environment were used for data processing.

RESULTS: The optimal operating parameters of the proposed new working body for basic tillage have been determined, and a diagram of the force interaction of the working body of the deep tiller with the soil is given.

CONCLUSION: As a result of the research, the reasonable parameters of the working body of the deep tiller for antierosion tillage were found, the chisel length, the soil crumbling angle (installation to the bottom of the furrow), the distance between the working bodies in the longitudinal and transverse directions when placed with a ledge at an angle of 30 degrees to the motion direction were determined.

BACKGROUND: One of the basic requirements for the tracked vehicle spatial motion simulation models to be used for multiple simulations or to be embedded into driving simulators and into controllers of the on-board control systems is high computational efficiency.

AIM: The article describes the development of a simulation model of a high speed tracked vehicle powertrain with step track gear boxes to be inserted as a subsystem into a highly computationally efficient model of the tracked vehicle curvilinear motion.

METHODS: In order to increase the model efficiency, the dynamics of the transmission gears is neglected, their internal kinematics being described by their gear ratios. External kinematics of the transmission is provided by the algorithms of the drive wheel speed regulators. The engine torque is defined as a function of the engine crankshaft rotational speed. The engine crankshaft is coupled to the transmission by means of the dry friction model simulating the operation of the friction gear-shift mechanisms of the track gear boxes. The simulation model of the powertrain has been implemented in Matlab\Simulink and built as a DLL module into a three-dimensional multi-body model of the tracked vehicle chassis dynamics developed by the author in the Universal Mechanism MBS-software.

The resulting integrated model was used for the simulation of the tracked vehicle steering in different gears and calculation of theoretical minimum turning radii.

RESULTS: The radii obtained by simulation are in good agreement with the radii calculated from the gear ratios of the powertrain under research.

CONCLUSION: The developed powertrain model based on the drive wheel speed regulators can be used as a subsystem of a highly computationally efficient model of the tracked vehicle curvilinear motion.

BACKGROUND: Most of the main livestock products in the coming years will be produced on existing farms under collective lease conditions, as well as on individual farms, which will ensure intensive management of the industry.

AIM: Study and obtaining of theoretical and analytical dependencies to justify the design parameters of the feeding device in the facility for the preparation of liquid feed mixtures.

METHODS: The presented facility for the preparation of liquid feed mixtures is a multifunctional technical device capable of performing three functions: dosing the material (a whole milk substitute), supplying liquid (the pumping function) and preparing the mixture (the mixer function). The corresponding calculation schemes for determining the parameters are given.

RESULTS: An analysis of the working bodies of machines and mechanization for transporting dry components shows that a screw body, manufactured according to scientifically based recommendations, can meet the requirements and characteristics of the component supplied for mixing.

The process of separating the dry component and moving it to the impeller is as follows. The dry component is located in the loading chamber 1 and then, under the gravity, it falls on the feeding device 2, which moves the feed to the impeller. In case of translational motion of the machine, the wedge-shaped lower edge of the screw housing is inserted into the roller component and separates it from the surface, which then enters the working area of the screw. The auger mills part of the dry food with its flights and moves it to the impeller of the facility.

CONCLUSION: The obtained theoretical and applied analytical dependencies make it possible to determine the design parameters of the screw, including the screw pitch to diameter ratio, which must be taken into account when designing facilities for preparing mixtures with the supply of a dry component to the impeller. This method can also be used for writing computer programs.

BACKGROUND: Knapsack-type lever-arm sprayers are manually operated by farmers to apply chemicals in the field, which is time-consuming, labor-intensive, and costly. Prolonged use can cause discomfort in the hands, shoulders, and waist of operators, leading to fatigue. This problem can be affordably overcome by some mechanical maneuvers.

AIM: This research aims to develop and evaluate a wheel-operated, knapsack-type sprayer machine suitable for row crops.

METHODS: The machine integrates a lever-operated sprayer with a wheel-driven mechanism, transferring power via a chain and sprocket system. The sprayer’s performance was evaluated in both workshop and field conditions, considering factors such as nozzle discharge, spray angle, coverage area, swath width, and efficiency.

RESULTS: The machine was made to serve at variable heights of crops, and its field efficiency was measured at 88.46%. A break-even analysis indicated 34.13 ha as the minimum acreage that must be sprayed for the sprayer to be profitable. The cost of fabrication (USD 105.93) was found to be affordable by marginal farmers of low- to middle-income countries.

CONCLUSION: The developed wheel-operated sprayer is effective in field conditions, offering improved ease of use and reduced drudgery in pesticide application.

BACKGROUND: For the successful separation of potato tubers from the soil, it is necessary to consider the interaction of these tubers with the working bodies of potato harvesters. It is important to determine the forces acting on the tuber in the bed, as well as the parameters that may contribute to the damage of the tubers during mechanized harvesting. It is necessary to identify the damage criteria and to optimize work processes for reducing the loss of tubers due to insufficient separation of soil mass and other factors.

AIM: Calculation of the tuber stress caused by the influence of the working parts and theoretical determination of the contact pressure acting on the tuber from the soil considering the condition of damageability of potato tubers.

METHODS: The finite element method (FEM), which allows performing a detailed analysis of stress distribution at contacts between the tubers and working bodies, is used.

RESULTS: The possibilities of applying the Hertz contact problem to the calculation of permissible parameters of load on a tuber were theoretically studied and the values of the permissible contact pressure were determined: q_к = 0.034 MPa for a metal working body, q_к = 0.15 MPa for an elastic one. At the same time, damage to potato tubers equipped caused by an elastic working body is significantly reduced.

CONCLUSION: Contact loads that occur in tubers during interaction with metal working parts exceed the permissible stresses on the tuber, which causes damage to the tubers. To eliminate this drawback, the surface of metal working parts should be made elastic.

BACKGROUND: The throughput capacity of the combine harvester’s thresher q_k is determined with permissible grain losses of 1.5% of its total amount collected in the combine bunker. The range of grain mass supply, for example, from a minimum of 0.5–1.0 kg/s to q_k is called the operating characteristic of the thresher (OCT) of a grain harvester. The actual grain loss in the considered supply range is less than 1.5%, but their overall value is unknown. Nevertheless, this is the most important indicator of the combine harvester’s efficiency, since these losses are summed up (for example, at the level of 1–1.2%) and can reach a significant value. Therefore, the assessment of the combine harvester only in terms of throughput is insufficient for efficiency evaluation, since the combine harvester operates at the throughput level rarely, and in the OCT mode, grain losses are summed up every second.

AIM: Development of the criterion for evaluation of operation efficiency of a combine harvester’s thresher by grain losses at operating modes.

METHODS: In the paper, the new method for evaluation of the efficiency of a combine harvester is proposed. Statistical dependences of grain losses change depending on change of grain mass supply to the combine harvester are used. The throughput capacity of the combine harvester’s thresher in kg/s is determined with grain losses behind the thresher at the level of 1.5%.

RESULTS: Numerous laboratory-field tests have revealed a close correlation between the four threshing parameters (engine power and separation area of the concave, straw walker and cleaning, and the dynamics of grain loss growth depending on the grain mass supply with great reliability in the range of the OCT feeds is approximated by a logistic dependence. For practical calculations, the software has been developed. This makes it possible to compare harvesters of different designs with each other faster.

CONCLUSION: For the first time, to evaluate the efficiency of the combine harvester’s thresher, a new criterion named as “average integral operational losses of grain behind the thresher in the operating range of grain mass supply” is introduced. An increase in grain losses behind the thresher was detected with an increase in the throughput of the combine harvester. The optimal harvesting area, during harvesting of which the growth of grain losses per unit of grain mass supply is compensated during the operating mode of highly-productive combine harvesters, is determined. The optimal harvesting area depends largely on the throughput capacity of the combine harvester and the harvesting conditions according to the state of the soil fertility and the zonal sequence coefficient, that is the degree of adaptability of the combine harvesters to the zonal features of the soil fertility and the applied methods of machine use. When calculating the economic efficiency of combines, it is advisable to consider the average integral operational losses of grain for alternative versions of combine harvesters and, on this basis, give them a more comprehensive evaluation. The use of the logistic function of grain losses from the grain mass supply to a combine harvester and, on its basis, the introduction of the criterion of average integral operational losses of grain behind the combine harvester’s thresher represents scientific and practical novelty.

BACKGROUND: In agricultural areas with insufficient and unstable moistening, the shortage of soil moisture has a clear impact. Various methods of tillage are used to conserve and accumulate moisture effectively and to establish an optimal moisture-temperature conditions of the soil.

AIM: Study of the influence of the methods of tillage on soil moisture and temperature conditons.

METHODS: Studies of soil moisture and temperature, in soil horizons at a depth of 30 and 55 cm, were carried out on ordinary carbonate heavy loamy chernozem. Four variants of main tillage were compared: flat-cut, layered, dump and without tillage. During the research, the meteorological conditions of the observed period were taken into account.

RESULTS: It was found that at a depth of 30 cm and 55 cm, the soil on the agricultural background without treatment (No-till) was the most humidified and had humidity values of 40.40% and 69.79% respectively. Relative to it, soil moisture in other agricultural backgrounds was reduced by 9.42% and 18.37% respectively with the flat-cutting method, by 10.79% and 33.31% with the layered method, by 16.32% and 30.88% with the dump method. The temperature condition of the soil at a depth of 30 cm and 55 cm on the agricultural background without treatment was the most cooled and had values of 15.06 °C and 12.00 °C, respectively. Relative to it, the soil temperature in other agricultural backgrounds was increased by 1.93% and 7.75% respectively with the flat-cutting method, by 5.38% and 7.50% with the layered method, by 6.91% and 6.83% with the dump method.

CONCLUSION: It was revealed that the agricultural background without tillage has the most stable moisture-temperature regime of the soil, which is an advantage when introducing this type of tillage in agroclimatic zones with a semi-arid climate.