卷 85, 编号 4 (2018)

Nowadays one of the most urgent problems of creating modern combustion engines (ICE) is the problem of ecology. Ensuring environmental requirements is usually associated with the introduction of new structural elements or the modernization of existing structures, since practice shows that the use of traditional methods to reduce the toxicity of exhaust gases, leads to a gradual deterioration in the fuel economy of the engine. This article discusses the use and development of an exhaust gas recirculation system for a transport diesel as the most effective means of reducing NOx emissions into the environment. On the example of expert data, the experience of using exhaust gas recirculation systems in diesel engines is considered, and their main advantages and disadvantages are given. The use of «cooled» exhaust gas recirculation is more preferable than «uncooled», since the filling of the cylinders with an air charge improves, and lower gas temperatures during the combustion period are provided, thereby reducing the amount of NOx generators. It is also noted in the work that when a cooled exhaust gas recirculation system is used in conjunction with optimization of engine design and adjustment parameters, NOx emissions are reduced with minimal deterioration of the engine's power and economic parameters. On the example of research and simulations on the testbench of the transport engine 8ChN 12/13, the efficiency of the exhaust gas recirculation system on diesel has been estimated and all the necessary data was provided. Due to the optimization of the adjusting parameters and the developed model of the exhaust gas recirculation system, it was possible to achieve 46 % reduction in NOx emissions. It has been shown experimentally that the use in a diesel engine of a theoretically developed organization of working processes with the use of recirculation of exhaust gases and the characteristics of controlling the main adjustments of the combustion process is advisable.

Coulters are installed for cutting sowing grooves on the seeding-machines. The most common are disk, keeled, razor-shaped, rocker coulters. The disadvantage of disc and razor-shaped coulters is the formation of the unsealed bottom of the sowing groove, which contradicts the agrotechnical requirements. According to the recommendations, pre-sowing soil cultivation should be conducted no later than a day before sowing. However, it is practically impossible to sustain this over the whole area. Weeds appear at the period between the presowing treatment and sowing. According to the known data of Russian and foreign scientists, if, for example, weeds are not removed in tomato crops in the first 10 days, yields are reduced to 50 %. Therefore, the coulter must be equipped with a weed plow. The seed bud must penetrate as soon as possible into the lower layers of the soil and provide seed buds with water and nutrition. This task is solved by slicing when sowing the underseed gap. The field germination is ensured by close contact of the seed with the soil. Now this is achieved by installing a rolling compactor behind the coulters. However, surface compaction of the soil makes it difficult for seedlings to leave the day surface. In addition, moisture is pulled up and the weed seeds located in the upper layer, where the soil temperature is higher, grow quickly. We do not need a soil compactor, but an action directly on the seeds, ensuring their close contact with the soil. A multifunctional coulter, that has a share with 80 mm-wide shank, which is able to make seed drill of 25 mm width, a spring bar slitter for slicing underseed slit and a 3 mm diameter rod seal to ensure seed contact with the soil, was developed. Descending from the column dry soil covers groove with a thin 15...20 mm layer.

Complex mechanization of selection and experimental works allow to significantly increase the volume of obtaining high-quality seeds and improve the efficiency of all breeding activities. During the harvesting of crops, from the plots everyday up to 5000 items in bunches and up to 1500 pieces of beets are harvested. The total weight of the harvest per day is within 500 kg. Harvesting of plants from the plots of the first stage is carried out manually by cutting the plants with a sickle, scissors or pulling out with the root system. The number of samples requiring analysis for the season is estimated by many thousands, for example, only in selection nurseries are prepared for each crop up to 15-20 thousand plants. This is the most time-consuming operation in breeding. The number of plots in the II stage also reaches several thousand pieces for each crop. The attempt to mechanize the cleaning of single-breed plots at the I-II stages, both in Russia and abroad, has not yet yielded results for mass and effective application. In this regard, the VIM started developing a new domestic technical means for harvesting grain crops at the I-II stage of breeding in 2011 to reduce the cost of the technological process in primary seed production using elements of existing mowers and trimmers. Prototype of the new mowers under the brand name ТС-0,2 was made by MZOK VIM plant. Taking into account the accumulated experience in the study of the ТС-0.2, in 2017, the work on its modernization was carried out in the VIM. In addition to the elimination of deficiencies in the design introduced additional elements to improve the work such as the table-flooring for cut stems. The technical parameters of the trimmer are justified on the basis of physical and mechanical, dimensional and morphological properties and characteristics of the stem of the selection crops, the size of the selection plots and the size of the stems in a row. Harvesting machines of this type are quite popular, but, unfortunately, their production is not mass and this does not allow to organize their mass production.

The article is devoted to the disinfection of grain and seeds of agricultural plants in the agro-industrial complex. The pesticides, systemic fungicides, used for this purpose, in particular, lead to the development of resistance of parasitic microorganisms, as well as toxicological consequences for the environment and humans. The article suggests a new method of decontamination using a variable magnetic field of low frequency. The subject of the research was the regularities of the process of magnetic disinfection and the characteristics of technical means for its implementation. The purpose of the research is the development of initial requirements for the equipment for magnetic disinfection of grain, constructive proposals for the creation of such equipment. Research methods included analysis of internal processes in biomaterials under the influence of an alternating magnetic field, analysis of the parameters of the devices necessary to create the required field. On the basis of analytical studies, the initial requirements for magneto-disinfecting equipment and its main part - the electromagnet are formulated. An example of the practical implementation of a device that meets the initial requirements is given. The device is an electromagnet based on an asynchronous motor. The principle of magnetic decontamination and the proposed device have been tested experimentally: for the wheat grain with a total infection of fungal and bacterial infections 41 % (controlled), the reduction was achieved to 17-12 %. Critical characteristics of asynchronous motors are considered and it is concluded that certain types of engines are most consistent with the initial requirements and, therefore, are the best basis for the proposed device. In general conclusions, the 5AI112MB8, 5AI112MB6 or similar engines are recommended, while it is noted that devices based on them can work in parallel in a general decontamination unit, which multiplies the productivity. The final conclusion shows the perspective of the new technology associated with the elimination of the disadvantages of chemical etching and the advantages over other electrophysical methods in the uniformity of processing, energy efficiency, compactness and low equipment cost, the absence of harmful emissions and emissions.

The wide use of the finite element method for the strength analysis of the undercarriage elements requires a reliable method of the load's calculation. Conventional analytical method of the load's calculation does not take into account their redistribution due to the kinematics and dynamics of the elements. An alternative option is the numerical dynamic analysis with the use of the spatial dynamical models taking into account kinematics and flexibility of the undercarriage elements. The article describes a method of the strength analysis of a tracked vehicle undercarriage for the case of a track-type tractor with gross weight 72 ton. The method is based on the combination of the undercarriage multibody model for the simulation of the loads in typical operation modes and finite element models of its parts for calculation of the strain-stress and margin of safety in each load case. The undercarriage is described as a set of rigid bodies connected by springs and dampers at all interaction points between the undercarriage elements, the track-shoes, and the ground. The loads on the undercarriage are calculated by the numerical integration of the equations of motion. The time histories of the loads are used for the detection of the static strength critical load cases. Each critical load is transmitted to the finite element models of the analyzed undercarriage parts for the subsequent strength analysis. The method is demonstrated for the «tractor forward pitch during the lifting of the earthmoving blade» and «tractor moving over a single rail» load cases. The article shows the analysis of the time histories of the bogie loads. The authors discuss issues of the load transmission from the multibody model to the finite element models of the undercarriage parts and demonstrate some results of the strength analysis of the bogie.

The random nature of the load is the main cause of deterioration of energy parameters and technical and economic indicators of machine-tractor units (MTU). Oscillations of the load lead to an increase in energy costs for technological processes. Direct fuel and energy costs should be determined and predicted with a high degree of reliability, taking into account the specifics of the work of the MTU and the dynamics of its performance of technological processes. The identification and optimization of energy costs of the MTU will ensure an increase in the efficiency of the technological processes and technologies of cultivation in crop production. The subject of the study is the development of mathematical models for determining and optimizing the direct energy costs of MTU equipped with advanced gas turbine engine (GTE) engines. The purpose of the research is to develop a methodology for determining the direct fuel and energy costs of MTU, taking into account the probabilistic nature of the load. The novelty of the research consists in the developed mathematical models and calculation algorithm, as well as optimization of the direct fuel and energy costs of MTU with GTE. The proposed methodology is developed on the basis of a systematic approach, generalization, and analysis of experimental data, mathematical modeling of processes. Experimental studies were carried out in laboratory facilities and in the field using modern measuring instruments and recording experimental data. The proposed methodology allows, with a probability of 0,90-0,95, to predict the optimal values of the direct fuel and energy costs of the MTU with GTE. As an example, the article gives examples of calculation and optimization of direct fuel and energy costs of plowing unit consisting of a Kirovets tractor with a GTD-350T gas turbine engine and a PNI-8/9-40 plow at various levels of turbocharger speed. It is established that at the 100 % level of the turbo compressor speed and the variation of the load variation coefficient from 0 to 0,333, the optimal values of the direct fuel and energy costs of the plowing unit increase from 543,0 to 723,12 MJ/ha. The same trend of increasing the direct fuel and energy costs of MTU is also observed in other levels of implementation of the turbo GTE turbocharger speed. It should be noted that with a decrease in the level of implementation of the turbocharger GTE's speed, direct fuel, and energy costs are increasing. The proposed methodology allows to determine and optimize the values of direct fuel and energy costs of MTU with GTE taking into account the probabilistic nature of the load under the specific conditions of their operation.