No 1 (2017)

Articles
Energy efficiency of the machine-tractor unit in transient modes
Fomin S.D., Avramov V.I., Gapich D.S., Vorontsova E.S.
Abstract
The study of transient modes of operation of the machine-tractor unit (MTU) in order to improve energy efficiency and energy saving is a very important task. The process of starting and accelerating of MTU is the heaviest mode of operation, which is characterized by considerable dynamic loads and which has a significant influence on the most important indicators: productivity, fuel efficiency, as well as slipping of propulsors, abrasion of the soil and tires, loading and lifetime of the elements of the transmission of tractors. One of the effective methods for reducing dynamic loading is the introduction of elastic-damping links in the drive of propulsors of tractors. The study of impact of elastic-damping drive of traction wheels on the parameters of the MTU operation during the acceleration period were carried out in a complex way: theoretically, on the six mass dynamic equivalent model developed by us, which adequately reflects the actual overclocking processes, and experimentally, in the field conditions on full-scale samples. Methods of software mathematical modeling and developed methods of experimental research were used. The complex of the conducted researches has established: due to the decrease in dynamic loads the improvement of all operational parameters of the MTA has been obtained, including: reduction in the slippage of propellers, tire wear and abrasion, a significant increase in energy efficiency: specific fuel consumption in the process of starting and accelerating of MTU with an elastically damping drive on stubble in gears from the third to the sixth decreases by an average of 40% compared to a rigid serial drive. Due to the smoothing of the peaks of the hook load (by 38%) and the torque (by 36%) with the elastic elements, a more smooth and at the same time more intensive acceleration of the unit is obtained (acceleration time is shortened due to the fact that the slippage is reduced and crankshaft speed is reduced in lesser degree).
Izvestiya MGTU MAMI. 2017;(1):2-7
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Selection of the main parameters of passenger automobiles D, E and F classes
Kravets V.N., Musarskiy R.A., Volkov S.A.
Abstract
The object of the study are passenger automobiles of D, E and F classes according to the European classification, manufactured in 2010-2015 at more than 80 enterprises in all the automotive countries of the world. The purpose of the study is to establish the dependencies of the curb and fully loaded weight of passenger cars on their main classification parameter - overall length. The novelty of the work is that models of modern automobiles were investigated, whereas similar studies were performed on automobiles that were mastered in production at the beginning of the 21st century, most of which have now been withdrawn from production. The performed work is actual, since its results make it possible to scientifically and reasonably choose the most important design parameters of passenger cars: curb and fully loaded weight. Based on the statistical processing of the initial data, analytical and graphical dependencies of the curb and fully loaded weight of automobiles on their overall length in each class were obtained and, in addition, in classes D and E, these dependences were established separately for automobiles with sedan, hatchback, coupe and cabriolet bodies. A total number of 1165 automobile models were analyzed. A large volume of the investigated models allowed to obtain statistically reliable results. The article shows that, with an error of 6.8% to 27.9%, the relationship between the masses and the overall length of cars of all the studied classes can be approximated by polynomials of the second order. The results of the research are recommended to be used in the design and research organizations of automobile concerns for a reasoned selection of the design parameters of the designed automobiles.
Izvestiya MGTU MAMI. 2017;(1):8-15
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Aspects of the development of the type of tractors and trends in the technical re-equipment of production units of various types
Okunev G.A., Kuznetsov N.A.
Abstract
Domestic and neighboring countries industry produce wheel and tracked tractors, which differ from each other by various parameters. The variety of general-purpose tractors offered on the market puts producers in the forefront of the choice of acquiring equipment to perform a set of technological operations. A comparative evaluation of the use of wheeled and caterpillar tractors of various traction classes on basic technological operations showed an increase in operating costs per unit of work performed with increasing parameters of tractors, especially wheeled propellers. The use of wheel tractors of high traction classes is accompanied by an increased specific pressure on the soil even on twin tires due to the increase in track width. Use of wheeled tractors with a power of over 350 hp on transport works is not advisable. This reduces the annual load and further increases the cost of performing technological operations. As a result, the competitiveness of a caterpillar tractor of high traction classes is substantially increasing. The wheel tractor is suitable only for maneuvering over long distances. As a result of the reform of agricultural production, a multi-fold system of economic activities of enterprises has developed. Along with large holdings and production units on the basis of former collective and state farms, a considerable proportion is made up of farm households. As a general-purpose tractor for farming a wheel-driven machine with engine power of 150-200 hp is used. A tractor of the MTZ-80 type is needed to perform auxiliary works to ensure the operation of the main unit. The tractors park of the large grain enterprises consists of high-performance wheeled vehicles of class 6-8, as well as class 3-4 tractors on wheels for auxiliary work. The bulk of the land in processing in the region is accounted by enterprises formed on the basis of former state farms and collective farms. These are diversified economies of grain and livestock farming. Multisectoral production allows to form a more developed structure of sown areas due to the cultivation of different cultures. To perform a set of works in these farms caterpillar tractors of class 4-5 and wheeled tractors of general purpose of class 3-4 are needed.
Izvestiya MGTU MAMI. 2017;(1):16-22
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Modeling of the processes of evaporation and mixture formation in the cylinder of a tractor diesel engine when working on an ethanol-fuel emulsion
Likhanov V.A., Lopatin O.P., Chuprakov A.I., Yunusov G.S.
Abstract
The article is devoted to the problems of modeling the processes of evaporation and mixture formation in the cylinder of a tractor diesel 4Ch 11.0 / 12.5 with a combustion chamber of the TsNIID (Central Research Diesel Institute) type when working on ethanol-fuel emulsion. In a diesel engine 4Ch 11.0 / 12.5 with a combustion chamber of the TsNIIDI type, when working on an ethanol-fuel emulsion, a volume-film mixture takes place with the predominance of evaporation of the fuel prior to the start of the combustion process. The evaporation of fuel depends not only on the dynamics of the motion of the medium and the temperature conditions, but also on the characteristics of injection and spraying. The speed and turbulence of the mixture are important characteristics. Therefore, the above parameters determine the intensity of evaporation and mixture formation. During the evaporation of droplets of ethanol-fuel emulsion and diffusion into the surrounding vapor-air medium, a combustible mixture forms. It does not ignite the fuel itself, but its vapor mixes with air. The constructed model takes into account the peculiarities of evaporation and mixture formation during the spraying of fuel and allows us to accurately calculate their speed. In regions where the concentration of droplets is low, calculations are made for one drop, and in zones with a high concentration, the interaction between the drops during evaporation and combustion is taken into account. In order to better understand the nature of the interaction of droplets with each other and with the surrounding turbulent gas flow, the entire combustion process is divided into stages: the formation of aerosol particles, the movement of droplets, their evaporation, mixing with the oxidant, ignition and combustion. The following basic assumptions are also accepted: there is a spherical symmetry of drops; The thermal conductivity coefficient, the specific heat are constant and do not depend on temperature; there is an identity of heat and mass transfer processes; the quasistationary nature of the process takes place.
Izvestiya MGTU MAMI. 2017;(1):23-27
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Experimental and computational study of the loading of parts of the wheel gear reducer of a snow thrower
Lyashenko M.V., Shekhovtsev V.V., Chebanenko A.P.
Abstract
The article presents an analysis of the results of the experimental study, during which the load was determined for the gear wheel shaft of the rear-axle gearbox of the all-terrain vehicle transmission on ultra-low pressure tires TREKOL-39041. These all-terrain vehicles have very good cross-country ability and are indispensable for off-road operation during mudslide or deep snow, but they often have transmission failures, especially the shafts on which the wheel reduction gear of both the front and rear axles are installed. In the transmission of these vehicles on the tires of ultra-low pressure, the units from a number of commercially produced vehicles were used. The use of such units reduces the cost of construction and simplifies the production technology, maintenance and repair, but also creates certain difficulties in the design of this type of ATV, in some cases, increases the weight and dimensions. The experimental data are compared with the data of other authors and with calculated data. The obtained data are compared with the experimental and calculated data on the loading of the transmission elements of the UAZ-31512 automobile, the main units of which are used in the layout diagram of the snow aerial vehicle. The results of the studies indicate that the main reason for the failure in the transmission of the snow thrower TREKOL-39041 is the operating conditions, including somewhat different from ordinary tires, the interaction of the ultra-low pressure tires with the best traction and coupling properties with the supporting surface, and a more complex transmission scheme, than for conventional all-terrain vehicles, in which the transmission is simply assembled from the units of a number of serially produced automobiles and calculations of the dynamic loading of its elements on the forced modes are not conducted, which leads to the appearance of significantly exceeding the permissible values of stresses in the splined joint of the wheel gear shaft, to its plastic deformation and failure.
Izvestiya MGTU MAMI. 2017;(1):28-34
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Mathematical model of the lateral traction of the tractor
Noskov N.K., Pozin B.M., Troyanovskaya I.P.
Abstract
The issues of the course stability of the movement of the agricultural tractor aggregate acquire the greatest urgency in the plowing, since an additional unfolding moment arises on the plow (due to the geometry of its working surfaces), which can lead the tractor aside from rectilinear movement. The operator often has to correct the movement of the machine, which contributes to rapid fatigue and, as a result, a decrease in productivity. The development of a mathematical model of the tractor's motion under the influence of an external eccentric load on the hook will allow to determine the limiting value of the shearing force. The drift of the tractor under the influence of external forces (without participation from the side of the driver) is a passive turn, which currently lacks sufficient attention in the theory of the curvilinear movement of the caterpillar tractor, since the theory of rotation is usually aimed at examining the active movement (under the driving influence of the driver ). The drift is a set of controlled rectilinear motion and uncontrolled shear under the action of the lateral component of force on the hook. Considering the low operating speeds of the tractor, it is possible to compile a quasistatic model of curvilinear motion in the drift, which consists of: differential equations of motion and equilibrium conditions of external forces with limiting friction. As a result of solving the system of presented equations, trajectories of the tractor's motion are obtained under different load on the hook. The model allows: to study the trajectory of motion on various ground backgrounds; find the optimal ratio of the weight of the tractor and the forces of resistance; to study the influence of the parameters of the working element (the attachment point of the plow and the angle of inclination of the plow surface) on the characteristics of motion.
Izvestiya MGTU MAMI. 2017;(1):35-39
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Method of calculation of probabilistic estimation of noise emitted by passenger automobile aggregates
Pobedin A.V., Lyashenko M.V., Shekhovtsov M.V., Dolotov A.A.
Abstract
The article deals with the problem of noise reduction of vehicles. Noise pollution is an important environmental problem. Currently, the level of urban traffic noise varies from 70 to 95 dBA, which significantly exceeds the current sanitary standards. The main source of vehicle noise is the engine and its systems. In the engine noise, the component caused by the combustion process and mechanical component are mentioned. The next most important source of noise are transmission units. In them, noise is generated by gears, bearings and fast rotating shafts. Tires of a moving vehicle are one of the main sources of vibration and noise at high speeds (from 80-90 km / h). Sources of noise of aerohydrodynamic origin are stationary or nonstationary processes in gases. One of the most intense aerodynamic sources of noise is vortex formation in flowing parts of mechanisms. When the vehicle is moving in the air stream, it is a source of turbulence, so noise increases with increasing speed. The authors carried out a number of experimental studies of the noise emission of individual units of a automobile - engine, gearbox, cardan gear, differential, exhaust system. Taking into account the results of experimental studies, a technique is proposed for the probabilistic calculation of the vehicle noise. A mathematical model is developed for calculating the expected noise in the passenger compartment of passenger automobiles, which allows obtaining not only the mathematical expectation of noise levels from each unit and its spectral components, but also their dispersion. On the basis of the model, a program has been created that makes it possible to obtain the spectral noise components from each of the sources in one-third octave bands with an estimate of the probable range of their values (confidence intervals) even at the design stage of the vehicle, which allows us, at the design stage, to lay down the necessary characteristics of the noise emission of aggregates and the automobile as a whole. The created technique can be successfully used also for an estimation of characteristics of noise emission of other vehicles - cargo and other automobiles, buses, wheeled and caterpillar tractors, agricultural machines.
Izvestiya MGTU MAMI. 2017;(1):40-46
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Unmanned mobile vehicle for monitoring agricultural and forest land
Porubov D.M., Belyaev A.M., Beresnev P.O., Filatov V.I., Zezyulin D.V., Makarov V.S., Belyakov V.V., Kurkin A.A.
Abstract
Deterioration of the fertile condition of bioactive soils, agricultural and forest lands, as well as coastal zones of reservoirs from the intensive agricultural, industrial, transport and resource-producing activities of mankind increases exponentially with each passing year. More than 30% of the reclaimed lands are in unsatisfactory condition. More than 18 million hectares of territory around industrial enterprises have a high degree of pollution, including heavy metals and toxic substances. The global area of the economic zone, intensively mastered by man, is 36% of the area of the water area of the World Ocean. Continuous monitoring is required to control the level of pollution and take measures to eliminate them. There is both a remote and a land (stationary and mobile) way of monitoring the environment. To automate the ground monitoring process, it is proposed to use unmanned vehicles equipped with a special instrument cluster. The article considers both foreign experience in the use of robotic complexes in the field of agriculture and forestry, as well as the domestic development of a mobile robotic complex, whose chassis can be used to monitor the condition of soils, forest lands and water bodies. The place and types of conducted chassis tests are described, the main technical characteristics are given. Presented equipment used for autonomous movement of the complex. The results of studies of the relief and physico-mechanical properties of the track are given, which make it possible to increase the mobility of the robotic complex. Based on the results of the tests, relevant conclusions were drawn on the possibility of using the developed robotic complex for environmental monitoring, works in the field of agriculture and forestry, further goals for its improvement and improvement were set.
Izvestiya MGTU MAMI. 2017;(1):47-56
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Physicochemical properties of Euro standard diesel fuel
Khodiakov A.A., Khlopkov S.V., Bernatskiy V.V.
Abstract
It is known that the quality of diesel fuel is characterized by both performance indicators and environmental properties of fuel. At the same time, the introduction of modern norms and standards that are associated with the modification of the component composition of fuel sets the task of controlling the physicochemical properties of diesel fuels. To solve the task, fuel samples, purchased from different fuel producers, and diesel fuel samples with an unknown prehistory, stored for a long time in the laboratory, were investigated. Mixtures of fuel with kerosene were also investigated. Diluted kerosene fuel, when it is used, reduces not only the power, but also the engine life. The density of the objects of the study was measured with oil meters. The viscosity and fractional composition of the fuels were determined using the VPZh-4 viscosimeter and the ARNS-1E oil distillation apparatus, respectively. Cetane numbers were measured by the OCTAN-IM indicator. As a result of the carried out researches it is established that the density, viscosity, fractional composition of diesel fuels correspond to those presented in the GOST standards. The acidity of samples with a long storage time and an unknown prehistory is greater than the GOST indicator value. The average value of the cetane number of diesel fuels measured by the OCTAN-IM indicator and different from the parameters required by the regulations is identical to the value given in the world fuel charter standard (ISO 5156). In all, without exception, fuels are present unsaturated and aromatic hydrocarbons. It is shown that in the fuel produced by different manufacturers, the ratio of unsaturated and aromatic hydrocarbons can be different. The density, viscosity and other characteristics of the mixture containing 10% kerosene are identical to the normalized values for diesel fuel. The density of the mixture containing 30% kerosene is not only below the norm, but also below the measured values of the density of diesel fuels.
Izvestiya MGTU MAMI. 2017;(1):57-62
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Increasing the efficiency of the catalytic converter
Solomin V.A., Shabanov A.V., Shabanov A.A., Kiliushnik V.M., Mladenskiy A.V.
Abstract
The article deals with the efficiency of the catalytic converter of automobiles in operation with the aim of solving the problem of reducing the pollution of the atmospheric air by the exhaust gases of automobiles. The problem of reducing emissions of harmful substances of vehicles is considered to be one of the main. The article presents calculations of the efficiency of the neutralizer at various operating conditions of the internal combustion engine, and factors influencing the process of oxidation-reduction reactions are determined. It is shown that a small amount of oxygen (О2) to the neutralizer limits the oxidation processes and does not give a good reduction efficiency for CO and CH. At an О2 concentration of 1.7 to 0.75% up to the neutralizer, the efficiency of the oxidation reactions in the neutralizer is maximal. The main requirements for the process of catalyzing harmful emissions and the disadvantages of modern neutralizers are considered. The main contribution to emissions of CO and CH is made by the modes of starting and warming up of engine. This is especially felt in the cycle of "cold tests" of the automobile under the UN Rules No. 83-06. Emissions of hydrocarbons increase proportionally with a decrease in engine temperature. In this regard, new types of neutralizers are provided to ensure the achievement of catalytic reactor activity at a lower temperature than those currently used on automobiles, as well as on-board vehicle diagnostic systems that support the environmental characteristics of vehicles in operation. The reasons for the "aging" of the neutralizer during its operation, the methods for diagnosing the neutralizer for the purpose of assessing its technical condition and on-board monitoring systems are analyzed. The urgency of the task of improving the design of the automobile in terms of limiting toxicity and the system of technical control in operation was noted. Improvement of the environmental control of vehicles is primarily related to the operability of on-board diagnostic systems of the car in operation and the catalytic neutralization system. The normative base of the Russian Federation and the EU in the field of environmental control of motor vehicles in operation is given.
Izvestiya MGTU MAMI. 2017;(1):63-71
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Method for determining probabilistic estimates of the specific fuel consumption of a gas turbine engine as a part of arable unit
Shkrabak V.S., Dzhabborov N.I.
Abstract
The article describes the method for determining the probabilistic estimates of the specific fuel consumption of a gas turbine engine as a part of arable unit. When justifying mathematical models for determining probabilistic estimates of the specific fuel consumption of the gas turbine engine, the method of the random argument function of professor L. Ageev was implemented. To improve the accuracy of calculations in determining the probabilistic estimates of the specific fuel consumption of a gas turbine engine correction factors (or functions) and formulas for their determination are proposed. The mathematical expectation of the specific fuel consumption, the inverse of the normally distributed argument, in this case the effective power of the gas turbine engine is not equal to the reciprocal of the mathematical expectation of the argument. This inequality varies depending on the coefficient of variation of effective power, which should also be taken into account when determining the dispersion and the standard deviation of the specific fuel consumption of the gas turbine engine. Experimental studies of arable unit consisting of a gas turbine tractor (GTT) with GTD-350T gas turbine engine and a mounted plow with variable width PNI-8 / 9-40, to verify the reliability of mathematical models of probabilistic estimates of the specific fuel consumption of the gas turbine engine, were conducted in the fields of training and experimental household of the Saint-Petersburg State Agrarian University. The proposed method allows to determine the average and optimal values of the mathematical expectation, variance, standard deviation and coefficient of variation of the effective specific fuel consumption of the gas turbine engine in the composition of various agricultural units.
Izvestiya MGTU MAMI. 2017;(1):72-77
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Control of dynamics of tractor with electronic gearshift control
Timofievskiy A.A.
Abstract
The article deals with control of process of tractor unit acceleration from the standpoint of meeting the requirements imposed on the dynamics of the tractor: the maximum value of the tractor acceleration and the maximum acceleration growth rate. As in the electro-hydraulic shift control the pressure in the switchable friction clutches is controlled by a feedback effected by proportional hydraulic valves, the pressure change process is considered to be exponential. The time constant of this process is defined. It is established that the simultaneous acceptance of the permissible values of the maximum acceleration of the tractor and the maximum growth rate of the acceleration (jerk) determines the calculated value of the time constant of the process of changing the pressure in the included friction clutch during the acceleration period. There were determined the parameters of the calculated acceleration process and the basic values of the pressures in the friction clutches, which are used in the formation of the program for changing the pressure in the clutches when changing gears. From the positions of dynamics and heat losses in friction clutches the influence of the structural difference in the hydraulic schemes of the pressure supply to the clutches and the progress of the tractor acceleration is estimated. Some variants of forming a pressure change program are considered that allow, with unfavorable design characteristics of the pressure supply to the clutches, to meet the requirements for the dynamics of the tractor when shifting gears. The results of calculations performed with the help of the mathematical model of the dynamics of the tractor in the course of gear shifting, the values of the dynamic parameters and the friction work in friction clutches for various characteristics of hydraulic pressure supply systems, or for various programs of pressure change are presented. The analysis of calculation results is carried out; conclusions are drawn and recommendations are given.
Izvestiya MGTU MAMI. 2017;(1):78-88
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