Архив за Август, 2016

Increasing the calorific value of motor fuels

    Yu.V. Vorob’ev (1), DSc in Engineering
    A.V. Dunaev (2), PhD in Engineering

    (1) Tambov State Technical University, Tambov, Russia, tmm-dm@mail.nnn.tstu
    (2) All-Russian Research Institute of Technology for Repair and Maintenance of Machine and Tractor Fleet, Moscow, Russia, dunaev135@mail.ru

Abstract
The results of the studies of mechanochemical activation of motor fuels aimed to increase their calorific value and reduce their consumption in automotive internal combustion engines are summarized. Traditionally, the improvement in fuel efficiency and environmental friendliness of such engines is achieved by high-tech modernization of fuel systems. But it can also be achieved by modification of fuels that changes their properties and increases the calorific value. By means of methods of mechanochemistry, using the equipment with low power consumption and a simple process, the mixtures and separate oil fractions are destroyed with the formation of low molecular homologs, as well as hydrogen and carbon. The degradation of saturated hydrocarbons is the breaking of chains, and unsaturated ones are destroyed through the formation of saturated products. The hydrogenation by degradation products of the starting material is possible. The mechanochemistry of fuels is investigated on the example of a combined static mixer-activator. The activator in the form of cylinder of 150 mm length and 30-50 mm diameter is used for modifying motor fuels; it has three serial camera, embeds in any of the fuel systems of internal combustion engine, does not require the drive, is free of chemical substances, does not affect the performance of gasoline, diesel fuel, aviation kerosene, fuel oil, does not reduce the engine lifetime. The tests were performed on a test bench with YaMZ-236 diesel engine using three different diesel fuels, at first with installation of activator in the fuel supply line of fuel high pressure pump, and then in its main drain line. When idling of diesel engine with engine speed of 900-1300 rpm, the reduction of activated fuel consumption on average by 26.3% is revealed in eleven tests. The methods for improving the calorific value of fuels by different impacts are reviewed.

Keywords:
mechanochemistry; activator; hydrocarbon cleavage; fuel consumption.

Analysis of design quality of tillage machines for agricultural engineering small-scale mechanization means of 0.2 tractive class

    S.N. Devyanin, DSc in Engineering
    I.I. Sapozhnikov, Engineer
    V.A. Shmonin, DSc in Engineering

    Russian State Agrarian University – Moscow K.A. Timiryazev Agricultural Academy, Moscow, Russia, pakedova.55@mail.ru

Abstract
Such operational parameters of small-scale mechanization means as grasp width and motion speed of a unit equally affect the machine performance and thereby determine its complex quality. The improvement of machine performance due to the extension of grasp width is reached by the use of three-, five-, six- and eight-furrow ploughs. This direction requires the constant increasing of traction force of power vehicles due to the increasing of engine power and trailing weight, which finally change the operational qualities of machine. Other direction of performance improvement is due to the increasing of operation speed; it is more complicated because when the speed increases, the traction resistance of working organs of tillage machines rises sharply, and the quality indicators of ploughed soil structure worsen. The transition to higher speeds of tillage requires a complex solution of such scientific and technical problem as development, creation and introduction of essentially new tillage machines for small-scale mechanization means. Special attention should be payed to a method for improvement of the engine power use by means of its transferring to working organs of the machine not through a hook but through a power shaft. Soil reaction to the active working organs is directed towards the power vehicle motion, therefore the trailing weight loses its functional necessity. It will allow to reduce the metal consumption of construction of small-scale mechanization means.

Keywords:
small-scale mechanization means; plough; plough surface; grasp width; ploughing depth; probability; statistics; indicators; parameters; mode; methodology; optimization; process; system; regulation; speed; tractive resistance.

Strategy for design improvement of a combine harvester

    V.N. Ozherel’ev (1), DSc in Agriculture
    V.V. Nikitin (2), PhD in Engineering

    (1) Bryansk State Technical University, Bryansk, Russia, vicoz@bk.ru
    (2) Bryansk State Agrarian University, Kokino, Bryansk region, Russia, viktor.nike@yandex.ru

Abstract
Promising directions of design improvement of combine harvester by means of the maximal adaptation of algorithm of its impact on plants with different physical and mechanical properties are presented. The technological algorithm of work with grain heap is optimized. It is proposed to separate previously the light impurities directly in the stripper header, the rear wall of which should be equipped with inertial tilted-plate separator. The light impurities are removed along with excessive airflow from the stripper header, but heavier free grain and tailings remain inside. In the terms of design, such technical effect is achieved due to the fact that the separator is formed by a set of longitudinal plates mounted with overlapping and imbedding of greater part of the cross section of each of them into the body of stripper header. The cross section of the plate has a curved surface, and its concavity is oriented towards the rear wall of the body. Remaining grain heap (tailings and free grain) is subjected to the secondary separation on perforated bottom of grain conveyor. Elongated holes are made in bottom; they have a particular cross-sectional shape and are inclined from the motion direction of conveyor flights on acute angle. As a result, the awns of spikes do not catch hold of the rear edge of the hole, and climb up the angled surface to the level of bottom of grain conveyor. Implementation of set of these technical solutions in the design of modern combine harvester will increase its performance when stripping of standing plants with eliminating the possibility of free grain crushing by working organs of the threshing device.

Keywords:
grain; combine harvester; stripper header; separation of grain heap; grain conveyor.

Study and calculation of soil compaction during operation and after stopping of a wheeled tractor

    D.I. Zolotarevskaya, DSc in Engineering

    Russian State Agrarian University – Moscow K.A. Timiryazev Agricultural Academy, Moscow, Russia, dina.zolotarevskaya@mail.ru

Abstract
Based on the results of theoretical studies and field tests, the mathematical modeling is performed for the processes of soil deformation and compaction during operation and after stopping of a wheeled tractor. The purpose of the study is to develop the earlier proposed calculating method of stress-strain state and soil compaction indicators during the operation of tractor and under soil creep after its stopping. The novelty of the paper consists in the fact that calculations are performed taking into account the viscoelastic properties of soil and changes of its density depending on time and on depth of deformable layer. The impact of soil load taking into account the viscoelastic properties of soil is described by a differential equation of first order connecting the compressive stresses, the rate of their change and relative deformations of compression. Viscoelastic properties of sward-podzolic light loamy soil revealed in field tests are considered. Soil density is variable by depth of its top deformable layer. Following the results of statistical processing of experimental data, the dependence of soil density on its depth before the impact of external loads is admitted as quadratic one. Computer experiments are performed; they revealed the indicators allowing to estimate quantitatively the changes of soil deformations, stresses and density during the operation of tractor and under soil creep after its stopping. Correlation dependencies of these indicators on the time, soil density and moisture, and on the speed of initial soil deformation are obtained. The proposed calculation method allows to find the above mentioned indicators for different depths of deformable soil layer, and also the stabilization time of soil deformation.

Keywords:
rheology; deformation; compressive stress; soil compaction; viscoelastic properties of soil; creep; mathematical modeling.

Mitigation of effect of compacted soil lump

    S.A. Sidorov, DSc in Engineering
    V.K. Khoroshenkov, PhD in Engineering
    D.A. Mironov, Engineer
    E.S. Luzhnova, Engineer

    All-Russian Research Institute of Agricultural Mechanization, Moscow, Russia, vim-avt@rambler.ru

Abstract
The article shows the effect of compacted soil lump which forms on the blade and in front of it on the characteristics of performance and lifetime of soil cutting working organs. Facts proving the presence of compacted soil lump on the blade in process of cutting soil layer are given. The results of theoretical and experimental researches are brought, allowing to obtain the design parameters and to improve the technical level of working organs used in soil cultivating and cutting. Negative factors that affect the efficiency of parts of tillage equipment in the conditions of compacted soil lump effect are substantiated and listed. The cyclical nature of its formation on the blade cutting the soil layer is noted. The article presents a hypothetical scheme of soil lump effect on the blade of working organ with different degrees of bluntness. This scheme explains the physical meaning of negative effects that are associated with deterioration of energy and agronomic indicators of parts and equipment during the operating wear in conditions of clear-cut compacted soil lump (on relatively strong soils). The article determines the fundamental reasons for the sharp increase in resistance of soil in the presence of chamfered edge on the blade of cutting working organ, which is associated with movement of compacted soil lump under the blade. Regularities defining the values of specific loads acting on the blade are given. The differences in variation of total and specific loads on working organ under formation of compacted soil lump are noted. The article substantiates a special role of the rear face of the blade of working organ in connection with heavy conditions of loading of soil layer under it. It describes the practical design and technological methods of protection of parts against the effects of compacted soil lump. Substantiated values of the parameters of working organs of agricultural machines interacting with soil are given, that provide the increase in their operational, agronomic and life characteristics.

Keywords:
compacted soil lump; soil cutting blade; working organ; cutting angle; experimental data; lifetime; thickness of blade.

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