Vol 89, No 6 (2022)

On December 23, 2022, the Ministry of Science and Higher Education of the Russian Federation presented awards to the laureates of the Prizes of the Government of the Russian Federation in the field of science and technology for 2022. The Prize of the Government of the Russian Federation was awarded to the work of the team of authors «Development of highly efficient wheeled transport and technological means for the accelerated socio-economic development of the territories of the Far North of the Russian Federation.» The honorary title of the Prize Laureate was given to a number of scientists from leading scientific institutions, including members of the editorial board, as well as regular contributors to the Tractors and Agricultural Machines journal.

BACKGROUND: The problem of using composite fuel (CF) in diesel engines consists in a wide variation of their physicochemical properties, which affect the emission of nitrogen oxides (NO_x) with ex-haust gases (EG). Therefore, the predictive assessment of the formation of NO_x with EG when using CF is very relevant.

AIMS: Predictive assessment of quantitative NO_x emission with diesel EG when using various types and compositions of CF. Scientific novelty lies in development of the method of prediction of NOx emission by a diesel engine when using CF.

METHODS: The method of prediction of quantitative NO_x emissions with diesel EG regarding the use of various CF kinds and compositions has been developed. Predictive indicators of NO_x emissions have been defined. Multi-parameter characteristics of NO_x emission with EG of the D-245.582 diesel engine of 4ChN 11.0/12.5 size have been obtained experimentally. Degree of convergence of the experimental data with the calculated values is assessed.

RESULTS: As a result of the carried-out studies, it was theoretically established that the load (p_e) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min^-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to increased NO_x emissions with diesel EG from 131 to 2225 ppm and from 75 to 1450 ppm respectively. The increase in NO_x emissions with the EG from 152 to 2125 ppm for CF consisting of DF and RO and from 175 to 1550 ppm for CF consisting of DF and E in the above mentioned operating modes experimentally confirmed. The degree of convergence of the experimental data with the calculated values is 90.14%, which in turn indicates the possibility of using the developed methodology as a predictive indicator.

CONCLUSIONS: As a result of the studies, it was established that the developed method of prediction of quantitative NO_x emissions with diesel EG is highly likely to use for preliminary assessment when various CF kinds and compositions are considered, as the degree of convergence of the experimental data with the calculated values, assessed with a statistical processing method and experimental error calculation, is 90.14%.

BACKGROUND: The subject of the study is the technological process of spraying field crops with slotted sprayers and the indicators dispersion.

AIMS: Improving the technological process of spraying plants with the use of pneumo-hydraulic slotted sprayers.

METHODS: Special equipment was used for photographing films of the liquid being sprayed under various operating modes of slotted sprayers with the possibility of calculating the size of the droplets. Fulfillment of the requirements for the number of drops/cm² at the treated object, overlapping the liquid spray jets ensures uniform distribution of drops over the spraying width. Therefore, it was sufficient to have information about the fragmentation of the thickness of the liquid film along the axis of the nozzle spray liquid into drops and obtaining their quantity per unit time depending on the flow rate of the working fluid.

Newness of the research lies in determining the effective operation of slotted sprayers as part of the spraying device.

RESULTS: With the use of the special equipment, it is possible to fulfill agrotechnical requirements for droplet sizes. When using herbicides for foliar post-emergence treatment with a systemic pesticide, the limits of MMD range are from 226 µm to 400 µm. Soil herbicide treatment with a systemic pesticide requires an increased droplet MMD range of 401 µm to 500 µm and >500 µm. The number of drops/cm² when using fungicides is limited from 50 to 70, insecticides – from 20 to 30, and herbicides – from 20 to 40.

CONCLUSIONS: The applied technology makes it possible to reduce the consumption of preparations and working fluid with high work performance and resource saving. The above research results can be used as the basis for determining the effective technology of a boom sprayer with slotted liquid sprayers. Fulfillment of the requirements for the number of drops/cm² at the treatment facility overlapping liquid spray torches ensures a uniform distribution of drops over the spraying width. Therefore, it suffices to know about the division of the thickness of the liquid film along the axis of the liquid spray jet into drops and to obtain their number per unit time.

BACKGROUND: Currently there is no simple and reliable algorithm of assessment of pressure on soil for the harvesters presented on the market. Therefore, analysis of the methods presented in active standards and used in calculation of pressure of propulsion on soil as well as development of the simplified and acceptable for manufacturing specialists method are relevant.

AIMS: Simplification of assessment of force action to wheels and soil during the operation cycle from the beginning and until the end of combine harvester tanker filling.

METHODS: The method of assessment of values of combine harvester wheel pressure on soil during the tanker filling operation cycle that allows exclusion of weighing of a harvester with a filled tanker is proposed.

RESULTS: As the result of studies, the complex of sequential actions of determining of load of machinery propulsion on soil, including determining of weight and center of mass coordinates for the grain inside tanker with the following determining of wheel normal forces caused by summarized load action of grain and a harvester (with an empty tanker) considering location of their centers of mass, was justified.

CONCLUSIONS: The new method application makes it possible to define maximal wheel pressure on soil with the filled tanker as well as the range of this indicator’s values from the beginning and until the end of tanker filling with grain. In this case, weighing of a harvester with a filled tanker at the special area with hard surface including the procedures of grain loading, unloading and weighing, is excluded. As a result, the ability of quick comparison of combine harvesters with the criterion of level of impact on soil in respect to tanker filling operational cycle beginning and end is ensured, which is the study subject. Thus, in order to solve the given task, it suffices to use the weighing results of harvesting machinery with an empty tanker, available in open sources, followed by calculation according to the proposed algorithm. Minimal divergence (less than 2%) of calculated and measured with use of platform scales values of maximal wheel pressure on soil is found.

BACKGROUND: The method of reasonable selection of an agricultural tractor tire set is a tool to compare and choose a tire set with the best properties, to analyze the features of tire-soil interaction, to evaluate the feasibility of installing the proposed tire set and to identify ways of tractor design improvement. The relevance of tire set optimal selection for vehicles operating in agriculture is related to the soil compaction by chassis that lead to a change of its structure and agricultural yield reduction. In addition, it is related to low traction properties which increases fuel consumption, reduces performance and accelerate tire wear during operation on soft soils with wheel slip.

AIMS: The aim of the study is to increase the operation efficiency of an agriculture tractor as part of a machine-tractor unit with the pneumatic tire set selected with the developed method. The research subject is the influence of tire design properties on the tractor operational indicators.

METHODS: The article presents the method that allows to choose pneumatic tires from a wide range of different models and manufactures according to known and available technical properties for a newly-developed or modified agricultural tractor. A specific feature of method is determination of a generalized parameter of tractor operation and using it for comparison of different tires instead of using individual indicators. Driving wheels pneumatic tires of different sizes and properties for a four-wheel drive general purpose tractor are used in calculation. The method includes analytical determination of agrotechnical, technical, technical-and-economic operational indicators of tractor as well as economic components such as: maximum pressure on soil; a transverse static stability angle of a tractor, a slipping ratio, tire set cost. According to the calculated indicators and tire set cost, a generalized parameter is determined with the Harrington method and used for selection of pneumatic tire set.

RESULTS: As a result of the method application, tire sets for the K-7M “Kirovets” agricultural tractor were determined such as: the 710/70R42 tires regarding the main operational indicators of the tractor and the 710/70R38 tires regarding the main operational indicators of the tractor and tire set cost.

CONCLUSIONS: The given method can be proposed to tractor manufactures for tire set selection, chassis evaluation and identification of ways of design improvement.

BACKGROUND: The results of R&D works on the laboratory prototype of a small disk harrow aimed for operation at mountainsides and capable to improve labor capacity and yield capacity of highland forage lands by 15–20% are presented.

AIMS: The developed laboratory prototype of a module of a mountain tractor-drawn small disk harrow for operation at sections of highland and piedmont areas capable to eliminate weed infestation of soil; to increase fertility and yield capacity of forage lands, to ensure stability of grass areas against deflation and erosion.

METHODS: The technical examination of the laboratory prototype of the machine was carried out at the highland station of North Caucasian Research Institute of Highland and Piedmont Agriculture in Dargvas village, Republic of North Ossetia-Alania at the altitude of 1540 meters above the sea level and at the slope angle of up to 12°. The properties of the testing conditions and the functional properties of unit operation were determined. The technical examination of the scientific documentation of the laboratory prototype of a module of a mountain tractor-drawn small disk harrow for cultivation of soil of highland grass areas was carried out in compliance with the GOST 33687-2015 standard. The subject of the study includes operating tools (the disks), distance between neighboring disks, disk curvature radius, disk diameter as well as the design of operating tools mounting at the frame of a small disk harrow.

RESULTS: The laboratory prototype of a small disk harrow for soil cultivation at sections of highland and piedmont areas was developed and produced on the basis of a minitractor. The small disk harrow is represented as a tractor-drawn unit with inline arrangement of 9 spherical disks mounted to individual struts. The design of the mountain small disk harrow is provided with the capability of the unit to switch from the right-to-left mountainside operation mode to the left-to-right mountainside operation mode when turning and with the optional mounting of press wheels.

CONCLUSIONS: Practical use of the module of a small disk harrow ensures reduction of generating processes ofmountainside sections, increases yield capacity of forage lands, ensures stability against water erosion and wind erosion as well as increases environmental stability and efficiency of grassland farming.

On November 2, 2022, the Honored Mechanical Engineer of the Russian Federation, Doctor of Technical Sciences, Professor Konstantin I. Gorodetsky, the author of a number of works on transmissions of tractors and agricultural machines, died. Konstantin was born on January 11, 1932. He graduated from the tractor department of the Moscow Automotive Institute (MAMI). An important achievement of K. Gorodetsky in the scientific plan is his proposed refinement of the formulas of V. Mishke, which make it possible to evaluate the change in the efficiency of rotary hydraulic machines with a change in their operating mode. The resulting formulas are called “Gorodetsky’s formulas”.