No 3 (2018)

Articles

Swelling of samples of automotive rubber products in standard fluid, engine oil and tribotechnical compound

Azanov A.V., Bernackij V.V., Razuvaev P.E., Hlopkov S.V., Hodyakov A.A.

Abstract

In this paper the change in the properties of rubber products of automobile under the influence of temperatures and when working in an aggressive environment was studied by authors. The radial tire protector samples (Barum 155/70 R13 75T Brillantis 2) with dimensions not exceeding 2×10-2×1.5×-2×5×10-3 [m], seal samples (of 2108-170342-01 type) in the form of a semicircle of 2.7·10-2×7·10-3×2·10-3 [mm] size, both original and aged rubber samples were tested. Aging was carried out in a stream of air, forcibly pumped through the reactor with the rubber placed in it. The heat treatment time was 12-100 hours, the temperature was 70-150 ° C. The change in the properties of rubber was evaluated by the parameter of the change in the mass of the samples (original and aged) after their contact with the liquid. The resistance of rubber to the action of liquids was studied, the kinetics of rubber swelling was studied. As the standard liquid the isooctane (2,2,4-trimethylpentane) was used. The experiments were carried with synthetic engine oil (SEO) “GENESIS CLARITECH” 5W-30 and tribotechnical composition (tribotechnical compounds; TC) “ACTIVE PLUS” (“suprotec”). The use of tribotechnical composition as a test fluid for rubbers was motivated by the purpose of assessing the chemical activity of the “suprotec”, when used in engines operating under conditions of high loads. The kinematic viscosity of SEO and TC was determined (in the temperature range from 20 ° C to 100 ° C) by the HPLC-4 viscometers, the density (ρ) of the liquids was measured with oil-meters. The hardness of the rubber samples was evaluated by measuring the resistance of the rubber by immersion of the indenter (a spring-loaded rod) into it. The indicator of the hour type ICh-02 (accuracy class 0) was used as a gauge.
Izvestiya MGTU MAMI. 2018;(3):2-8
pages 2-8 views

Development of vehicle undercarriage with roadster body using topological optimization

Basov A.O., Smirnov A.A.

Abstract

Nowadays the key task of designer is to reduce the mass of the automobile. This requirement is dictated by increasing demands for efficiency and dynamics of vehicle. On the other hand, the constantly increasing requirements for comfort and safety of the automobile, as well as the degree of automation of the driver's work lead to the use of a large number of additional systems, which increases the weight of the vehicle. In addition, the use of alternative power plants leads to the appearance of non-standard layout schemes. The number of manufactured models is increasing to satisfy all consumer groups. Simultaneously, the time period for R&D is reduced. In these conditions, we consider that it is effective to use methods of topological optimization of the undercarriage at the stage of the choice of the power circuit and the concept of the undercarriage. The article deals with the process of topological optimization of the vehicle undercarriage with roadster body. The car was developed at the Bauman MSTU. The process of developing of vehicle layout and design of driver position using a virtual manikin are shown. The process of preparing the design space for a computational model for optimizing is considered. A description of the finite element model for optimizing the undercarriage is given. There are considered two groups of calculation cases: operational and emergency. The optimization problem is formulated, the objective function and constraints are given. When performing calculations, the OptiStruct software was used. The results of optimization of the undercarriage for several loading regimes are presented. The analysis of the obtained topology is carried out.
Izvestiya MGTU MAMI. 2018;(3):9-14
pages 9-14 views

The method of determining the efforts of the pre-tightening of bolts to a bearing of the crankshaft, automobile and tractor engines

Gots A.N.

Abstract

The increase of power density of automotive and tractor engines leads to increased loads on parts of the crank mechanism. To ensure the specified reliability indicators, it is necessary to give an accurate analysis of the loads. There was studied currently used technique for calculating the pre-tightening force of rod bolts or mounting bolts of main bearing caps to ensure that the density of the junction of the threaded connections. It is shown that, first when the bolt is tightened, the liner shrinks by the amount of its protrusion and only then the joint is closed between the cover and the crank head of the connecting rod. This reduces the effort to ensure a given margin of safety of the joint density. The calculation of the force for deformation of the insert on the amount of its protrusion is carried out, which ensures the fit of the inserts when they are inserted into the bearing bore. It can be seen from the calculation that the force to deform the liner is not less than 30 ... 40 % of the value of the force of the tightening, which ensures the tightness of the joint between the components to be tightened. A procedure is proposed for determining the pre-tightening force of the connecting rod bolts or bolts for attaching the main bearings of the piston engine crankshaft, in case of providing the specified margin of joint density as a standard threaded joint. An example of calculating the torque settings connecting rod bolt for diesel engine D-245 when operating on the maximum idle speed.
Izvestiya MGTU MAMI. 2018;(3):15-20
pages 15-20 views

Method for calculating the characteristics of a linear type peristaltic pump with incomplete compression of the working member

Grishin A.I.

Abstract

The introductory part of the work contains brief information about the existing peristaltic pumps and their application areas. Special attention is paid to the use of miniature peristaltic pumps with a linear located tube. For such pumps, there is a sufficient number of experimental studies, but a very limited number of studies are devoted to modeling the flow in such pumps. The aim of the work is to develop a technique for calculating the characteristics of a peristaltic pump with a linear located tube and several squeezing elements that not completely compress it in the transverse direction, , based on a quasi-stationary model and verifying the applicability of the developed model by numerical modeling. A quasistationary model is obtained by compiling the Bernoulli equation for the instantaneous velocities and pressures for the current movements of the squeeze element. To evaluate the limitations of the applicability of the quasi-stationary model, numerical experiments were performed in the STAR-CCM + program taking into account the possibility of cavitation, for which the Eulerian polyphase model was used. Numerical experiments have shown that cavitation takes place at intervals when the pump discharge member returns to its initial position and the pressure in the compression area decreases. From a comparison of calculations with different pump cycle times, it is established that cavitation is essential only if the squeeze elements move too fast and the pump cycle time is sufficiently short. It was also found that fluctuations in fluid velocity within the pump are observed under the same conditions as cavitation. Comparison of the results of numerical simulation and calculations using a quasi-stationary model has shown that the calculations give an error in the time intervals when there is a simultaneous movement of pump squeeze elements. As a result of the analysis of the obtained results, it is concluded that the developed quasi-stationary model can be used for calculations if the viscosity of the pumped liquid is not less than 40 mPa •s and if the pump operating frequency is sufficiently small that the pump does not experience the specified cavitation and speed fluctuations.
Izvestiya MGTU MAMI. 2018;(3):21-31
pages 21-31 views

Comparison of the analytical solutionof efficieтcy regenerative rotating heatexchangethe device with resultsof numericalcalculations

Kalnitsky F.E., Kostyukov A.V.

Abstract

The article is devoted to the thermal-hydraulic calculation of the rotating heat exchanger of a gas turbine engine. More specifically, the purpose of this work is to determine the error of the known analytical calculation of the efficiency of the regenerative heat exchanger in comparison with numerical calculation. Analytical and numerical calculations of the rotating heat exchanger are performed. The main problem of creating a methodology for the analytical solution of processes occurring in rotating heat exchangers is that it is necessary to solve the problem of non-stationary heat transfer from the hot coolant to the coolant through the regenerator packing. The solution of any non-stationary process of heat transfer requires knowledge of the boundary and initial conditions of the process. As initial conditions, it is necessary to use the dependence of the regenerator packing temperature field on the steady state of its operation. Such a relationship can only be obtained after the calculation is completed. In this case, the solution of the heat transfer problem in a rotating heat exchanger is possible using two methodological approaches. The first possibility is a solution by successive approximations. In addition to the fact that such a technique is very time-consuming, it allows us to obtain only a numerical solution of the problem, the possibilities of analysis are limited. The second possibility is the use of one or several assumptions. Such an analytical solution was obtained by Stepanov G.Yu. It is clear that the use of assumptions in analytical analysis or in analytical calculations requires an assessment of the accuracy of the methodology. An estimate of the accuracy of the analytical solution to the efficiency of a rotating heat exchanger is given in the proposed work. It is shown that the error of the analytical solution of the regenerator efficiency in the zone of high regeneration degree values is insignificant in comparison with numerical calculations. Analytical solutions proposed by Stepanov G.Yu., are accessible and effective in the process of creating regenerators. Of particular importance are analytical calculations of the efficiency of regenerators when recording solutions in the form required by the similarity theory. An increase in the error in the analytical calculation of the efficiency of the regenerator is noted with a decrease in the ratio of the water equivalents of the heat-transfer packing of the rotating heat exchanger and coolants (gas and air). Marked increase of error of the analytical calculation of the effectiveness of the Regener-Torah in the decrease of water equivalent heat transfer gaskets. no-return heat exchanger and coolants (gas and air).
Izvestiya MGTU MAMI. 2018;(3):32-39
pages 32-39 views

Age of aerodynamics of automobiles

Korolev E.V., ZHamalov R.R., Bernackij V.V.

Abstract

The article analyzes the time variation of the values of the coefficient Cx and the aerodynamic factor for passenger vehicles of leading companies. Calculated equations of aerodynamic indexes are presented, both for the whole array of automobiles and for breaking them into classes according to the European classification. The analysis uses aerodynamic indicators of the main types of bodies of vehicles obtained both during road tests and in experiments in wind tunnels with full-scale objects. Examples are given of the discrepancy between aerodynamic indicators and the results of the correlation studies of automobiles produced under different conditions, in different wind tunnels and its comparison with road tests. The reasons for these discrepancies are indicated. Examples are given of the change in aerodynamic indicators from the time of the release of generations of some brands of automobiles. The best and worst vehicles in aerodynamics for all six classes of European classification are indicated. The novelty is the determination of the regularity of the change in aerodynamic parameters, in particular of the aerodynamic factor, for the whole period of development of motorization, which requires the use of a large data set. The results of the analysis are also given. The result of the analysis is the conclusion that the amount of the aerodynamic factor of passenger vehicles is decreasing for the whole time of automobilization with a change in the external form of the body.
Izvestiya MGTU MAMI. 2018;(3):40-50
pages 40-50 views

The toxicity study of diesel engines working on biofuels based on methyl alcohol

Lihanov V.A., Lopatin O.P.

Abstract

The paper substantiates the need for the use of biofuels based on methyl alcohol in diesel engines. At the same time, such environmentally friendly energy sources as methanol and methyl ether of rapeseed oil were investigated. The physical and chemical properties of these biofuels are presented. In order to develop, determine and optimize the composition of environmentally friendly biofuels for diesel engines, their tests were carried out when working on methanol with methyl ether of rapeseed oil and methanol-fuel emulsion. It was experimentally established that the use of environmentally friendly biofuels in diesel engines is possible in the form of alcohol-fuel emulsions (methyl alcohol - 25%, detergent-dispersing additive succinimide C-5A - 0.5%, water - 7%, diesel fuel - 67.5%) and in the form of a separate supply of methyl alcohol (88%) and methyl ether of rapeseed oil (12%). When using methanol as a biofuel for diesel engines, it is possible to significantly reduce the emissions of soot particles and nitrogen oxides due to the fact that during the combustion of alcohol in the combustion chamber of diesel, less intermediate products (in relation to diesel fuel) are formed, contributing to the birth of acetylene and aromatic hydrocarbons, which lead to the formation of soot. Methyl alcohol, with its simpler structure and small molecule sizes, is one of the determining factors for more “pure combustion” of fuel. Experimental studies of diesel engines on environmentally friendly biofuels of the above compositions were carried out and a promising solution to improve their environmental performance was justified. When the diesel engine is working on a methanol-fuel emulsion, the content of nitrogen oxides in the exhaust gases is reduced by 41.3%, carbon black by 85.5%, carbon dioxide by 6.7%, carbon monoxide by 45.0%; when working on methanol and methyl ether of rapeseed oil, nitrogen oxides by 47.4%, carbon black by 90.4%, carbon oxide by 44.8%.
Izvestiya MGTU MAMI. 2018;(3):51-57
pages 51-57 views

Investigation of the main factors of the process of ignition of a homogeneous mixture from compression in an ICE

Makarov A.R., Smirnov S.V., Kostyukov A.V., Ponomareva K.A.

Abstract

An overview of the advantages of an engine with the ignition of a lean homogeneous mixture from compression (HCCI), among which, above all, economic and environmental indicators are presented. There were considered the disadvantages of this engine, hampering the release of batch production, and the main is the difficulty in providing in the combustion chamber the conditions for self-ignition of the working homogeneous mixture near TDC in the entire range of engine operating conditions. The ways of solving the problems of controlling the ignition of the working mixture in the combustion chamber, reducing the noise level and fighting the occurrence of shock loads with increasing load, starting the cold engine and improving the engine with the HCCI process are presented. The main ones can be a combination of distributed and direct injection using variable valve timing and exhaust gas recirculation, the joint use of controlled turbocharging and exhaust gas recirculation, a change in the heating of the working mixture at the inlet to the engine, external and internal exhaust gas recirculation (EGR) phases of gas distribution, regulation of the chemical composition of fuel and changes in the intensity of heat transfer and the dynamics of temperature growth in the cylinder, primarily due to changes in the piston crown temperature. The results of computational studies of the influence of various parameters on the process of ignition of a homogeneous mixture on compression are presented. It is established that the greatest effect on the process of homogenization of the air-fuel mixture is caused by an increase in the surface temperature of the bottom of the piston. Reducing the diameter of the fuel droplets from 0.1 mm to 0.03 mm results causes an increase in the relative mass of evaporated fuel by a factor of 2. Increasing the temperature of the fuel at the inlet also effectively increases the relative mass of the evaporated fuel.
Izvestiya MGTU MAMI. 2018;(3):58-64
pages 58-64 views

Digital PID controller for pneumatic and hydraulic systems

Truhanov K.A.

Abstract

In the development of technological systems with pneumatic or hydraulic drive, the use of automated means for their control is required. At present, automated control tools built with the help of logic controllers are widely used. The logical controller allows to solve a wide variety of tasks with minimal costs, both in terms of cost and time spent for developing the system. So the logic controller ensures the speed of systems with pneumatic or hydraulic drive up to 1 ms or less. With the use of digital automated controls, questions related to the synthesis of PID regulators and the stability of systems with pneumatic / hydraulic drive in the time domain arise. The purpose of this work was the creation and practical implementation of a digital PID controller for controlling the pneumatic / hydraulic system to provide practical recommendations for its use in engineering. The article presents a block diagram of analog and digital control systems with a proportional pneumatic distributor. The implementation of analog and digital PID-controller and optimization of its parameters by an integral criterion is presented. Comparison of analog and digital systems with the PID controller introduced into their composition is made. The quality of these systems is suggested to be estimated in the time domain by the time of the transient process and the maximum dynamic error. Practical recommendations for determining the sampling time of digital systems with a PID controller are given. An example of the developed digital automatic control system for tracking pneumatic drive is shown, its structural diagram, the general view of the control device with the logic controller and the graphic operator interface, which makes it easy to configure the automated control tool and monitor its state. The scientific novelty of the results presented in the article was that the task of investigating the dynamics of a pneumatic / hydraulic distributor with an electric control in the time domain was solved using a mathematical model that included a digital PID controller and a comparison of the results of modeling a digital system with analogue was made, and practical recommendations for determining the sampling time were given.
Izvestiya MGTU MAMI. 2018;(3):65-75
pages 65-75 views

The training of specialists in sphere of power engineering

Fomin V.M., Gots A.N.

Abstract

The tasks of this work are: analysis of trends in the development of engine building, which relates to the important direction of power engineering, and assessment of the quality of training of engineering and technical specialists in domestic universities, investigating the conformity of their professional knowledge with modern requirements. It is emphasized that the process of training engineering and technical personnel in the field of power machine-building specializing in internal combustion engines should be constantly improved taking into account the rapid development of modern engine building. The factor of the qualitative level of training specialists possessing the necessary knowledge in the field of technology and the development of highly efficient engines acquires important state significance. The tendencies of development of engines for transport and transport-technological facilities are considered. It is noted that foreign companies have far gone in the implementation of innovative technical solutions associated with a significant complication in the design of engines, systems. Successful practical implementation of these solutions has become possible, among other things, thanks to the high level of training of foreign specialists with the necessary knowledge in the field of technology. The problem of the emerging decline in the level of university training of engineering personnel in the sphere of Russian energy engineering is analyzed. Moreover, over the past decades, Russia has experienced a tangible need for skilled engineers and technologists, who have been and continue to be the backbone of domestic production. It is emphasized that all this can lead to the loss of promising technologies in the production of competitive domestic engines, and will cause catastrophic consequences for the country's economy and its defense capability.
Izvestiya MGTU MAMI. 2018;(3):76-82
pages 76-82 views

The method for determining the rational parameters of the kinematics of the suspension systems for high-speed tracked vehicles

Cipilev A.A., Sarach E.B.

Abstract

The requirements for the suspension systems of modern high-speed tracked vehicles impose many limitations, forcing the designer to find unconventional structural and layout solutions. The trend of increasing the power-to-weight ratio of modern and advanced tracked vehicles, in turn, leads to an increase in the thermal load on the dampers, which results in the need to use a forced cooling system, which, together with the requirements for compactness of the chassis units, further reduces the available space for the suspension components. This makes it necessary to find such design parameters of the kinematics of the suspension system, which would ensure that all the requirements are met, taking into account the existing dimensional constraints. The method of choosing such design parameters is presented in this article. This method allows, using the geometric dimensions determining the mutual position of the chassis units on the machine, to find a rational arrangement of the space in the body of the high-speed caterpillar machine elements of the suspension system. This makes it possible to parametrize the kinematics of the suspension assembly for typical structural schemes for securing the pneumatic hydraulic springs (PHS) on the body of the machine, that means it makes it possible to analytically determine the rational distribution of the PHS to provide the most favorable power and kinematic transfer ratio at the design stage. The dependencies given in the article make it possible to assess the feasibility of implementing a particular kinematics, and also give an idea of the conditions that determine the most rational kinematic and power ratio to ensure the minimum dimensions of the PHS and the favorable form of the characteristic of the elastic element.
Izvestiya MGTU MAMI. 2018;(3):83-91
pages 83-91 views

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