Vol 83, No 4 (2016)

Articles

Mathematical modeling of evaporation of rape oil and ethanol in combustion chamber of diesel engine

Likhanov V.A., Romanov S.A., Araslanov M.I., Kozlov A.N., Suvorov A.N.

Abstract

The fuel evaporation in combustion chamber of diesel engine is decisive for the subsequent destruction of fuel molecules. The evaporation process in combustion chamber of diesel engine operating on alternative fuels is understudied. The paper is devoted to the theoretical study of evaporation process of ethanol and rape oil in combustion chamber of diesel engine. It is assumed that fuel spray consists of a great number of identical droplets. The diameter of these theoretical droplets is equal to the average volume diameter of real droplets. A mathematical model given in the paper takes into account the physical characteristics of fuel, design features of sprayer, temperature and pressure of gases in combustion chamber. The engine performance (temperature and gas pressure in combustion chamber) has been determined on a test bench in the Vyatka State Agricultural Academy. The engine worked on rape oil and ethanol with the use of binary system of fuel supply. The paper presents the results of theoretical calculations of evaporation of rape oil and ethanol in combustion chamber.
Traktory i sel hozmashiny. 2016;83(4):3-6
pages 3-6 views

Improvement of construction of a chisel plow

Shchirov V.V., Khizhnyak V.I., Nesmiyan A.Y., Khlystov E.I., Bobryashov A.P.

Abstract

The chisel plows represent a diverse group of tillers, which includes widespread constructions with working organs of a paraplow type mounted on a frame according to the arrow-shaped diagram. This arrangement has several advantages, but it also leads to the decrease of soil crumbling degree, increase of energy intensity of its loosening, decrease of stubble field safety. The study suggests to mount the working organs of chisel plow on a tool frame in pairs both in transversal and longitudinal directions in order to improve the efficiency of subsurface tillage. A chisel plow-ripper with the proposed arrangement of working organs has been tested in the North Caucasus Machine-Testing Station and recommended for implementation. With the view of efficiency assessement, the test results of the improved ripper were compared with the average performance of classical share and chisel plows. Comparative analysis showed that transversal pair arrangement of working organs provides the increase of soil crumbling degree by 17-21%. Thereby an optimal air-and-water regime for soil is formed, its contact with the roots of weeds is broken, which consequently provokes the ravage of offset weeds. More efficient use of energy supplied from tractor and the longitudinal pair arrangement of posts of working organs allow to decrease the specific fuel consumption by 20-27% in comparison with the analogs, to reduce the number of open furrows, to increase the stubble field safety, to reduce the unevenness of field surface more than twice.
Traktory i sel hozmashiny. 2016;83(4):7-10
pages 7-10 views

Anti-erosion package-combined tilling and sowing machine for strip tillage on the slope

Samadalashvili A.G.

Abstract

The paper describes a highly productive resource-saving anti-erosion combined agricultural machine for strip tillage of eroded soils on the slopes. The machine treats only the strips intended for sowing of certain width (20-30 cm) and depth (15-25 cm) without overturning. The border strips are resting, and they are to be treated in the years to come. The machine performs 6-8 agricultural operations during one field day; its working organs are arranged in two packages on the single common frame. The working organs of first package (hanging knives, deep tiller blades, covering knife and harrow) perform the loosening of soil layer without its overturning. The working organs of second package (sowing machine and packing wheels) perform the sowing and packing of plowed strip. The machine is a three-row one. The row-width spacing is 70 cm; the overall operating width is 170 cm; the plowing depth is 15-25 cm; the operating rates are 7-9 km/h; the hourly efficiency is up to 1.5 ha/h. The package-combined machine can be aggregated with tractors of 1.4-3.0 drawbar category. Due to the formation of mini inundation canals and maximum retaining of stubble on soil surface, the moisture is preserved in the soil for a long period of time, that leads to the thickening of humus layer of soil, to retarding of development of erosion processes, and as a result to the increase in productivity. Since the output per shift of the proposed tilling and sowing machine is by 2-2.5 times higher than under tillage by means of commonly used plows, and the consumption of combustive and lubricating materials and environmental pollution by exhaust gases are by 2-2.5 times lower, the machine should be considered not only as energy and resource-saving, but as environment-oriented one.
Traktory i sel hozmashiny. 2016;83(4):11-14
pages 11-14 views

Measurement of tractive effort at the drawbar of tractor in aggregate with mounted agricultural machine

Parkhomenko S.G., Parkhomenko G.G.

Abstract

Dynamometer test is used in scientific researches and in operation of tillage machines. It is necessary for completing of tractor units, for setting of rate of production and fuel consumption, and also for ensuring the control of technical condition of tractors and agricultural machines and correctness of their regulation. Under operating conditions, dynamometer test consists in determination of a horizontal component of tractive resistance of tillage machines. According to these data, it is possible to give the general comparative assessment of power consumption of various machines. There are methods of dynamometer test with the use of dynamometer frames, and also with the use of load cells, which embed into linkages and pins of the three-point hitch. All these methods have several disadvantages. Main of them is the use of several force sensors, which provides the lack of possibility of direct measurement of the total forces and raw errors of determination of the sought quantities. The aim of the research is to develop a device for dynamometer test of mounted agricultural machines, allowing to make the necessary measurements using one force-measuring sensor, without design changes of tractor and mounted machine. Presented dynamometer automatic coupler is made on the basis of two standard automatic couplers with a force measuring sensor mounted between them. Experimental studies showed the operability of the presented dynamometer automatic coupler. The proposed device is universal, it can be used with any tractor and any mounted agricultural machine and does not require design changes of tractor and agricultural machine. The application of one force measuring sensor enables the measurement with high precision.
Traktory i sel hozmashiny. 2016;83(4):15-19
pages 15-19 views

Three-dimensional supporting systems of frame construction for technological superstructures of agricultural purposes

Shkel' A.S., Zagarin D.A., Kozlovskaya M.A., Dzotsenidze T.D.

Abstract

New generation of transport and technological vehicles and agricultural transport means has been developed, based on the principle of design modularity with application of three-dimensional supporting systems of frame construction. Design decisions were implemented and introduced as the Ural-432065 all-wheel vehicle chassis with replaceable technological superstructures. A device for removing of replaceable technological superstructures from vehicle chassis and for their installing on support for storage was also developed. Three-dimensional supporting construction in the form of weld-fabricated steel pipe frame was selected. It was adapted for installation on technological superstructures and unified for bracketry on vehicle frame. Strength calculations were carried out. Sections of structural elements and method of their manufacturing were selected. Prototypes of devices were made on the basis of developed design documentation and installed on the superstructures: on the distributor of solid mineral fertilizers by means of threaded assembly; on the superstructure for hauling and subsoil fertilizing of liquid fertilizer organics by welding to load-carrying parts of the tanker. Computer simulation of the functional of replaceable technological superstructures allowed to estimate the efficiency of design decisions. Test results confirmed the data of analytical studies. Consequently, transport and process operations are implemented, both on open roads and in the field with satisfying of environmental and agrotechnical requirements. If there are several technological superstructures in the farm, it is possible to use only one vehicle chassis, which reduces the dead time and the impact of seasonality works factor.
Traktory i sel hozmashiny. 2016;83(4):19-23
pages 19-23 views

Analysis of a new equation of wheeled vehicle motion

Kuz'min N.A., Serdyuk V.I., Peskov V.I.

Abstract

Published works of professor G.I. Mamiti impinge on authority of the classical equation of traction balance developed by famed specialists of our domestic automobile science; he offers to substitute these time-proved theoretical developments for a new equation of motion. The purpose of this article is to analyse the validity of hypotheses used when establishing a new equation and to make a conclusion about its applicability for calculations of traction-speed properties of wheeled vehicles. Well-known laws of theoretical mechanics for lever-hinged mechanisms with special experiments and theoretical examples of various situations of wheeled vehicle motion are used as materials and methods of the analysis. G.I. Mamiti considers that moments due to air resistance force, inertia force, force from trailer and climbing resistance force, acting on vehicle body in longitudinal plane, create the opposing torques on driving wheels. It may only be correct for a monolithic structure, but assembled body and wheels constitute the lever-hinged mechanism. Moments, created by above forces, cause only the longitudinal roll of the body and the appearance of forces that lead to changing of normal reactions in suspension and axles, but do not create opposing torques on driving wheels. If the hypothesis of G.I. Mamiti was correct, the reactive moment on body from driving axle (or from cross-mounted power unit in the case of front-wheel drive vehicle), that was transferred, according to his considerations, on driving wheels, would be summarized with the torque transferred to them by transmission. As a result, traction force would be equal to zero, because these moments are identical in value and opposite in direction, so the vehicle could not move. Therefore, the wrong initial hypothesis leads to the establishing of wrong equation; its use, as it is shown in the article, leads to serious errors in calculations and to wrong conclusions on the improvement of wheeled vehicle designs.
Traktory i sel hozmashiny. 2016;83(4):24-28
pages 24-28 views

Impact of turbocharging on the startability of diesel engines in winter

Krokhta G.M., Khomchenko E.N., Usatykh N.A.

Abstract

The article explores the startability of diesel engine with and without turbocharger under cold conditions. It is known that under subzero temperatures typical for many regions of Russia, the startability of diesel engines is significantly deteriorated. The aim of research is to study the impact of supercharger on startability of diesel engines. In the process of experimental researches by means of light-beam oscillograph, the indices characterizing the starting sequence have been received, namely: rotational frequencies of crankshaft and turbocharger rotor, air output, time of starting, cylinder pressure. It is found that the startability of engine with supercharger conforms to the state standard requirements at the temperature of 8 degrees C below zero, whereas the startability of engine without supercharger conforms to these requirements at 12 degrees C below zero. The starting time of turbocharged engine is extended due to the resistance in inlet line, that leads to increase of inlet manifold vacuum, to decrease of final compression pressure and therefore to decrease of maximum cylinder pressure. The article determines the operation modes of turbocharger at the starting time and at post-launch warm-up. It is found that operating in these modes leads to the shortage of oil in turbocharger bearing under cold conditions. The research has shown that turbocharger mounted on the engine causes the significant reducing of delivery ratio, and therefore the deterioration of startability. Sustainable startability is possible with installation of circulation valve on engine inlet manifold or compressor, and also with use of turbocharger that can be switched off. It is found that turbocharger can operate in the mode of oil starvation at the beginning of post-launch warm-up under cold conditions. In order to reduce the wear of sleeve-shaft coupling, it is recommended to change the current scheme of oil filling or the design of turbocharger to provide oil inlet directly to turbocharger bearings in the moment of starter switching-on.
Traktory i sel hozmashiny. 2016;83(4):28-33
pages 28-33 views

Heat balance equation of air solar collector with heat accumulator

Kupreenko A.I., Komogortsev V.F., Isaev K.M., Chenin A.N., Shkuratov G.V.

Abstract

The aim of the paper is to find the mathematical dependence of temperature of heat-receiving surface of heat accumulator of a solar collector on its operating time under conditions of variable external factors. In this case, variable solar activity throughout the day is considered as the key external factor. Air solar collector with heat accumulator is a basic element of solar power plants intended, for example, for grain drying, water heating, natural ventilation systems of livestock houses etc. By the example of operation of a drum solar grain dryer with water heat accumulator, the differential equation of heat balance of solar collector is obtained. The equation takes into account the following components of heat balance: amount of heat coming into solar collector with atmospheric air; amount of heat coming from solar energy and absorbed by heat-receiving surface of water accumulator; amount of heat taken away by drying agent (warmed-up atmospheric air) after heat exchange with heat-receiving surface; amount of heat for heating of accumulator walls; amount of heat for heating of water in accumulator; external heat loss. On the basis of available experimental data, it is assumed that water temperature in accumulator is directly proportional to the temperature of its walls, and the enthalpy of atmospheric air is proportional to the flow density of solar energy. Required dependence of temperature of heat-receiving surface of a heat accumulator is found by solving the Cauchy problem for differential equation of heat balance of solar collector. The obtained exponential expression connects the parameters of variable external factors with design and technological parameters of a solar collector. This allows to model the output thermal performance of solar power plants used in agriculture depending on various external conditions.
Traktory i sel hozmashiny. 2016;83(4):33-36
pages 33-36 views

Influence of the number of undercarriage axles of mobile agricultural machinery on the depth of track

Shilo I.N., Orda A.N., Romanyuk N.N., Nukeshev S.O., Kushnir V.G.

Abstract

The deterioration of soil properties as a result of repeated impact of undercarriage of tractor units leads to the reduction in crop yields. Increasing of soil density caused by the impact of movers of tractors and agricultural machines results in increase of soil hardness by 2-3 times. To forecast the indices of undercarriage impact on soil taking into account the type and condition of soil fertility, as well as to determine the promising ways of improvement of undercarriages’ designs and their agro-ecological characteristics, it is necessary to substantiate the regularities of accumulation of repeated soil settlements under the impact of undercarriage. It is also necessary to determine the regularity of rise of settlement deformer under repeated soil load. The deformation at each subsequent soil loading is followed by stress rise in the contact zone as compared to the previous one. This is due to the increase in load intensity under repeated deformations, in particular due to the reduction of contact area of wheels with soil during repeated passing of tracks. This paper observes some dependencies which allow to determine the deformation of soils with different physical and mechanical properties under various operating conditions and parameters of undercarriages of tractor units. For the soil with high degree of compaction, the depth of track should be reduced by increasing the number of axles of undercarriage. For the moist soil with low degree of compaction, the movers with larger width of wheels should be used to reduce the depth of track.
Traktory i sel hozmashiny. 2016;83(4):37-41
pages 37-41 views

Kinematic analysis of connection of hydraulic cylinders of a forwarder crane under execution of defined motion of grapple

Piskunov M.A., Adamov D.V.

Abstract

The article deals with the kinematic analysis of forwarder crane; it determines the parameters of extension of hydraulic-cylinder rods for execution of defined trajectory of grapple motion. The current systems of forwarder crane control do not allow an operator to realize optimal trajectories and speed ability of motion of crane links. This disadvantage can be partly corrected, for example, with the use of automatic control of crane motion in certain phases of technological cycle. The analysis of matched connection of hydraulic cylinders of a typical forwarder crane is presented in the article. It determines how hydraulic-cylinder rods should move to provide the linear trajectory of grapple at the stage of motion from the moment of log gripping to the moment of its lodging in the middle of upper edge of a forwarder load space. It is necessary to provide a smooth acceleration at the start and a smooth deceleration at the end of grapple motion. The hydraulic-cylinder rods should also smoothly accelerate at the start of motion and smoothly decelerate at its end. The kinematic analysis uses well-known methods that are presented in the article in shortened form. It is shown that for typical design of a forwarder crane both conditions of smooth motion and linearity of trajectory cannot be fulfilled simultaneously. The results can be used for developing the algorithms of automatic control of crane at a separate phase of log loading when there are numerous points of log gripping (gripping control provided by operator) and one delivery point. There is no necessity in additional systems of environmental objects recognition at this phase, that allows to integrate these algorithms into the control system of a forwarder by low-cost facilities.
Traktory i sel hozmashiny. 2016;83(4):42-47
pages 42-47 views

Mathematical model of force lubrication systems of agricultural machinery and equipment

Malomyzhev O.L., Fedotova N.E., Medvedeva I.S., Prokop'ev I.S.

Abstract

The service life of engines and transmissions of agricultural machinery and equipment depends on wear intensity of their interacting parts (friction units). In its turn, the wear intensity of friction units is determined by friction losses and heat liberation in them. Optimization of operation of interacting parts and extension of their service life are provided by supply of rational amount of lubricant. Existing calculation methods of oil supply systems are based on the determination of volumetric flows. It is known that in engines, transmissions and hydraulic drives of agricultural machines, the oil is saturated with gas bubbles and gets the physical and chemical properties that differ from the properties of pure oil. That has significant influence on friction losses and heat liberation and causes more intense wear. On the base of the developed mathematical models, the impact of gas bubbles contained in oil on its physical properties (density, viscosity) has been analyzed. The lubrication systems of engines and transmissions of agricultural machinery have been analyzed, their parameters have been determined, including the types of channels of force lubrication systems which significantly influence on the formation of two-phase gas-oil medium. The article proposes the computational dependencies of motion of two-phase gas-oil mixture through the channels of force lubrication systems, which allow to determine rational parameters of channels at the stage of machinery design. That allows to ensure the supply of necessary amount of lubricant for minimization of friction losses, maintaining the required thermal regime of parts and minimization of their wear. Application of suggested mathematical model will allow to decrease the amount of life tests.
Traktory i sel hozmashiny. 2016;83(4):48-51
pages 48-51 views

The 90th anniversary of N.N. Kolchin

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Traktory i sel hozmashiny. 2016;83(4):52
pages 52 views

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