No 1 (2018)

Articles
Calculation investigation of the strength of the composite wheel rim
Bol'shikh A.A., Vdovin D.S., Eremin G.P.
Abstract
The aim of the research is to reduce the unsprung mass, the moment of inertia of the racing automobile’s wheel while maintaining the necessary strength due to the using of composite materials in its construction. Currently, the composite materials have been obtained a widespread usage as structural materials in the automobile assemblies and units. Particularly, the using of modern composite materials in the transmission elements of the automobile, such as drive shafts, axle shafts or wheels, makes it possible to substantially improve the performances of the wheeled vehicle: reduce the full and the unsprung weight. It is possible to point out from the modern composite materials, the polymeric composite materials having carbon fibers as a reinforcing element, which are possessing a low density and the best combining a high level of specific strength with producibility of the products. The object of the research is the racing automobile’s wheel which belongs to the class of “Formula Student”. The usage of composite materials in the construction of similar wheels, as well as the estimated evaluation of the wheel’s strength during its manufacturing from composite materials are discussed. The regulations of the competitions permit a great freedom in choosing the wheel construction. The estimated strength evaluation was carried out by the finite element method, the original finite element wheel model was developed for this purpose taking into account the anisotropic properties of the reinforced materials. The computational investigation of the strength of the selected construction showed that the rim which is made of the composite material has an excessive safety factor at the design loads. The proposed constructive decision allows to reduce the wheel weight by 33% (up to 1.68 kg) in comparison with the one-piece wheel made of magnesium alloys (2.5 kg).
Izvestiya MGTU MAMI. 2018;(1):2-9
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The automobile and tractor diesel engine, adapted to work on the liquefied hydrocarbon gas on the gas-diesel process
Izmaylov A.Y., Savel'ev G.S., Kochetkov M.N., Ovchinnikov E.V., Uyutov S.Y.
Abstract
The investigations were carried out on the brake bench equipment of the D-243 diesel engine manufactured by the Minsk motor plant. The system of distributed supply of the liquefied hydrocarbon gas with an ignition charge of diesel fuel by automatically changing the gas injection angle and incorporating into the exhaust gas recirculation system into the intake manifold was subjected to the tests. Adaptation of the diesel engine allows the feed system to work as in diesel mode and as well in gas-diesel mode, with the electronic control of diesel fuel supply in the “diesel” mode is more accurate and contributes to lower fuel consumption and more complete combustion of the diesel fuel into the exhaust manifold. Standard equipment which is widely used for the transfer gasoline engines with ignition from a spark plug, used for distributed supply of the liquefied hydrocarbon gas. The electronic control unit of domestic production was adjusted according to the methodology for controlling the supply of gas through the cylinders developed in the laboratory. The investigations have shown that the emission of pollutants into the atmosphere has decreased on all loading modes of the engine on the gas-diesel process and corresponds to the standard “Euro 4”. Due to half of the cost of liquefied hydrocarbon gas compared to the diesel fuel, the cost of using the latter is reduced by 20…25%. The usage of liquefied hydrocarbon gas in the gas-diesel engines ensures a reduction in the cost of production of agricultural products by 10…12%. These indicators confirm the relevance of scientific researches on the development of a system for adapting the diesel automobile and tractor engine to work on alternative types of fuel.
Izvestiya MGTU MAMI. 2018;(1):10-15
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Investigation of fuel injection in the Common Rail system on the unique scientific facility “Injection”
Kamaltdinov V.G., Markov V.A., Lysov I.O., Popov A.E., Smoliy A.E.
Abstract
A description of the unique scientific facility “Injection” for experimental investigations of the dynamics development of fuel torches under various conditions of injection into a constant-volume chamber is given. The facility is equipped with the Common Rail fuel systems with adjustable fuel pressure, compressed air supply from the cylinder, scavenging of the constant volume chamber, control of the bench, registration of control pulses, and high-speed video recording of processes inside the chamber. With the help of the controller-synchronizer, the moments of the beginning and the end of the electric pulse of the electromagnetic nozzle were controlled, simultaneous video recording of the Photron FASTCAM SA-X2 color high-speed video camera and the recording of oscillograms on a Tektronix TDS-2014C digital oscilloscope. The duration of the control electric pulse of the nozzle was set from 0,5 ms to 3,0 ms. The pressure in the fuel rail was set from 100 MPa to 165 MPa. The actual moments of the beginning and the end of the fuel injection were determined by the results of the video shooting and counted from its start. The delays of the beginning and the end of injection were determined by comparison the results of video-recording with recording the control electric pulses of fuel nozzle on the oscilloscope. The dynamics of the change in the length and angle of the cone of fuel torches were determined by measuring the contours of the visible parts of the fuel torches on the photorecordings. The delays in the beginning and end of fuel injection were practically 0,3 ms and 1,0 ms, respectively, at all the investigated modes. As a result the duration of the fuel injection process as a rule by 0,7 ms exceeded the duration of the control pulse. At the beginning of injection during 0,5 ms the velocity of the vertices motion of the fuel torches was 35…50 m/s, depending on the pressure, then it decreased to 31…38 m/s. It has been established that when the pressure in the fuel rail increases from 100 MPa to 165 MPa, the angles of cones of fuel torches decrease from 20º…22º to 17,5º…18,5º, that is, on average by 15%.
Izvestiya MGTU MAMI. 2018;(1):16-23
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Investigation of the driven disks of hydromechanical transmission BELAZ with the new LZ_G-Base oil and the friction materials FM-15 and MK-5
Reginya V.V., Il'yushchenko A.F., Leshok A.V., Rogovoy A.N., Gryazev D.A., Petrov V.A.
Abstract
At the mining dump trucks BELAZ with lifting capacity from 30 to 90 tons, loaders and bulldozers, special vehicles BELAZ for metallurgical production (slag trucks, heavy vehicles), aerodrome tractors, as well as for dump trucks and vehicles for underground works of the brand “MoAZ” are used hydromechanical transmissions OJSC “BELAZ” is the managing company of the holding “BELAZ-HOLDING”. The most important element of the hydromechanical transmission, which limits its service life and reliability, are the friction clutches for switching the stages and blocking the hydraulic transformer. The disks of friction clutches sustain significant static and dynamic loads, their surfaces are exposed to high specific thermal energy and intensive wear. During the tests it was established that for the sintered powdered friction material based on copper MK-5 (commercially used in the hydromechanical gearbox) it’s possible to increase the friction coefficient, decrease the stopping time and the wear rate by using the transmission oil LZ_G-Base. The sintered powdered friction material FM-15 has initially increased tribotechnical properties in comparison with material MK-5. The investigations of tribotechnical properties of sintered powder materials is currently being given to much attention. However, these studies do not consider the influence of lubricants on the operation of the sintered powder friction materials. The application of oil of type (LZ_G-Base) which is developed on Lubrizol technologies and G-Base base oils during operation of the sintered friction material FM-15 increases its tribotechnical properties by 10…15%. The conducted investigations of the driven discs for the hydromechanical transmissions BELAZ with the new gear oil LZ_G-Base and the friction materials FM-15 and MK-5 have showed that the tribotechnical characteristics are increased and the wear rate of the discs is decreased.
Izvestiya MGTU MAMI. 2018;(1):24-32
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The electric starting systems of automobile internal combustion engines with alternative sources of current
Maleev R.A., Shmatkov Y.M., Kholodov A.A.
Abstract
The application of capacitive energy storage devices in the electric starting systems for automobile internal combustion engines is considered, when instead of a standard battery, a battery of a smaller capacity is used, and in the remainder of the standard battery volume, the energy storage device is mounted. In this case, at the high specific indicators of the energy storage device, the reliability of the engine start can be increased with the same total volume and mass of the electric starting systems at low temperatures. The paper presents a methodology for a determination the parameters of the battery and the energy storage device which are connected in parallel for the electric starting systems, in the case when the type of internal combustion engine and its main parameters are specified, as well as the type of the starter motor and its characteristics. The conducted theoretical investigations made it possible to obtain the dependence of the required mechanical energy for starting the internal combustion engine from the value of the capacity of the energy storage device, as a result of which the required capacity of the energy storage device and its internal resistance, its initial energy, as well as its necessary volume and mass are determined. The volume and mass of battery can be determined from the reference literature or under certain methods for the specific energy of battery by volume and mass. If the ratio of the total volume of the battery and the energy storage device to the volume of the battery is less than unity, then at the given starting frequency of rotation, the usage of the energy storage device is reasonable, due to the reduction of the total volume of the electric starting systems. Similar calculations are conducted for other values of the average starting frequency of rotation. The optimal parameters of the battery and the energy storage device are in which the total volume will be minimal. The parameters of the electric starting systems with the energy storage device and the battery for the VAZ automobile engine with M6z/10G1 engine oil were calculated at a temperature of -20°C with a starter 35.3708 and the gear ratio of the drive gear 11,62. The results of the calculations are shown that for a specific energy of the energy storage device 1 Jcm3 at all starting rotational speeds, the usage of the energy storage device does not allow to reduce the total volume of the energy storage device and the battery in comparison with the volume of the battery required for scrolling the internal combustion engine shaft with this starting frequency.
Izvestiya MGTU MAMI. 2018;(1):33-37
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Ejector-type heat exchangers in the air conditioning in transport
Merkulov V.I., Popov A.A., Polikarpov A.V., Tishchenko I.V.
Abstract
In the modern world, the air conditioning systems have become the most widespread application and have become an everyday part of everyday life. However, due to the complexity of the construction during the designing of the air conditioning systems and the development of modern technologies, there are still many system’s assemblies that can be upgraded and improved. Along with such parameters as ergonomics and weight and size characteristics, a significant role is played by such parameters of the operation of the air conditioning systems as efficiency, reliability, resource. These parameters are particularly relevant in the context of miniaturization and work on a closed cycle in mobile transport vehicles (automotive, aircraft and ship equipment), since efficiency, mass and resource exert a determinative influence on the total cost of vehicles and the costs of its maintenance and operation. The main parameters that regulate the air conditioning systems are the temperature, flow rate and humidity of the supplied air. The article studies and compares the methods of primary cooling of hot air supplied to the helicopter's air conditioning systems, when the cabin is heated at low temperatures. Often this is done using air-to-air heat exchangers. In the materials of the article, it is proposed to consider the option of replacing one of such heat exchanger with an ejector-type heat exchanger, a description and comparison of the existing and proposed options for the modernization of the air conditioning system’s schemes, and estimate the acceptability of their implementation on the helicopter. Also, a comparative work was conducted to estimate the advantages and disadvantages of such a replacement. The primary estimated calculations of the change in the system’s parameters were implemented in the case of introduction of a replacement in all conventional load modes of a typical helicopter model. Specific features of the application of this replacement are given and additional innovations which are necessary for its implementation are pointed out. For calculations, the software complex ANSYS CFX, MathCAD, Solid Edge ST8 was used. In the course of the work, a construction and a method were revealed that provided the optimal parameters and method of implementation for the introduction of the ejector into the composition of the air conditioning system.
Izvestiya MGTU MAMI. 2018;(1):38-44
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Modeling of the mechanism of appearance of external infrasound of land vehicles
Nyunin B.N., Grafkina M.V., Sviridova E.Y.
Abstract
The main contribution to the acoustic pollution of residential areas is made by land vehicles including automobiles. Most scientific publications are devoted to the study of audible sound, its sources in the vehicle and the development of measures to reduce it. According to the authors opinion, at present the problem of the emergence and spread of infrasound in residential areas, and, accordingly, its negative impact on people and the environment is underestimated. Hence the development of computational and experimental methods for studying the mechanism of the appearance of infrasound from a vehicle is a very urgent problem. A large proportion of the acoustic radiation from the vehicle falls on infrasound and low-frequency range of frequencies. Depending on the design of the automobile, the occurrence of internal infrasound can be caused by the engine's vibrations as a rigid body on its suspension, flexural and torsional body oscillations, the impact of the oncoming airflow. Measurements of internal and external infrasound were carried out. A computational model is proposed and an assessment is made of the influence of the design features of the vehicle on the level of infrasound. Calculation studies of the mechanism of the appearance of an external infrasound of a vehicle have shown that its frequency and level depend on the speed of movement, the drag coefficient, the length and the Strouhal number. A significant source of infrasound in the automobile are also wheels that perform rotational and translational movements in the oncoming air stream. Calculation of five wheel harmonics for a automobile at various speeds of movement is carried out, existing dependences are revealed. The results of the calculation showed that exceeding the normative values of infrasound is possible only in residential areas adjacent to the traffic flow with speeds of over 80 km / h.
Izvestiya MGTU MAMI. 2018;(1):45-52
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Automated traffic control system based on recognition of the road scene and its objects
Porubov D.M., Beresnev P.O., Tyugin D.Y., Tumasov A.V., Belyakov V.V., Zezyulin D.V.
Abstract
Research and development in the field of driver assistance systems (ADAS) is being carried out to reduce the number of road accidents and improve road safety. Nowadays ADAS systems are widely spread, for example lane support assistant, obstacle detection on the lane, road signs, parking assistant, pedestrian identification system, night vision system, adaptive cruise control, blind zone monitoring system, etc. Driver assistance systems, which are developed by many large foreign vehicle manufacturers, have already been introduced serially and are being actively used on public roads. However, in the Russian Federation market there are practically no own developments and solutions, which can be installed in series on automobiles. The installation of foreign ADAS systems on domestic vehicles is difficult due to differing operating conditions, some differences in the types of road infrastructure, and also due to the high cost associated with the unstable economic situation. To implement the functions of ADAS on commercial vehicles, adapted to the conditions of operation in Russia, the team of Nizhny Novgorod State Technical University n.a. R. Alekseev together with the GAZ Group are working on the concept of a driver assistance system with the possibility of adjusting the movement of the automobile through integration into the steering system. The functional and hardware composition of the system is developed. Tests of individual components of the system were carried out in the part of recognizing traffic signs, determining and warning the driver about leaving the lane and about a possible collision with obstacles on the route. Integration of the driver assistance system with steering was carried out by means of data transfer via the CAN-bus of the vehicle. Based on the results of the tests, relevant conclusions were drawn about the efficiency of individual parts of the system and further goals were set for further development and improvement of the driver assistance system that promotes road safety and reduces the number of road accidents.
Izvestiya MGTU MAMI. 2018;(1):52-63
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Improvement of methods for calculating the interaction of propellers of multi-axle wheeled vehicles with barrier obstacles
Papunin A.V., Belyakov V.V.
Abstract
The paper presents theoretical and experimental studies of overcoming by multi-axis machines of barrier destructible obstacles. The review showed that the existing calculation apparatus is based on the assumption that barrier obstacles are not deformable, i.e. the walls of the obstacle have sufficient strength. It happens rare on the ground. One of the most difficult cases of off-road traffic is the overcoming of the multi-axle wheeled vehicle of the destroyed moat, as the walls of the ditch collapse as the wheels of the machine pass, which leads to its broadening. Deficiencies of the existing settlement apparatus were identified, and subsequently it was refined and supplemented. To verify the results obtained, experimental studies were carried out. As a research object, a small class all-terrain vehicle with a gross mass of 700 kg was chosen. Tests were conducted on the bank of the Volga River in the vicinity of the city of Nizhny Novgorod. As support bases, sand (homogeneous soil) and a compacted ground surface with a sod layer (heterogeneous soil) were chosen. According to the newly obtained dependencies, the theoretically possible maximum width of the moat being overcome, given its destructibility, was determined. Also on the selected support bases, their physical and mechanical properties were studied, using the PG-1 ground penetrometer and the research complex for accelerated studies of the properties of cohesive and disconnected soils “Litvinov Field Laboratory PLL-9”. In the future, dependencies characterizing the influence of various design parameters of transport-technological machines on the maximum width of the moat being overcome were obtained in the work, taking into account the destructibility of its walls.
Izvestiya MGTU MAMI. 2018;(1):64-74
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Frequency analysis of the system of stabilization of vertical reactions on the wheels
Al'salamekh B., Ryazantsev V.I.
Abstract
Increasing importance is given to the issues of road safety. Perfection of modern designs allows automobiles to move at a high enough speed. Taking into account the considerable size of the territory of the state and the variety of roads on which motor transport is operated, there may be areas with a pronounced periodic profile close to a sinusoid with different wavelengths from 0.5 to 1.5 m. On a road with a wave length of a periodic profile of 1 m at a vehicle speed of 36 km / h, the suspension system receives kinematic excitation at a frequency of 10 Hz. This value of the exciting frequency is in the range of real values of the natural frequencies of the wheels in the suspension systems of vehicles (5 ... 12 Hz). The resulting fluctuations in the vertical reactions of the road to the wheels lead to a decrease in the stability of the vehicle's movement. To solve the task of combating this phenomenon, a new method of increasing the stability of the vehicle's motion is designed - the method of controlling the vertical reactions of the road to the wheels when the car moves along periodic irregularities. The paper offers a frequency analysis of the properties of the stabilization system of vertical road reactions to wheels. Various variants of the control organization, algorithms formation using different types of regulators are considered. In particular, control options are considered with the use of proportional and proportional-differential regulators. The issue of the power consumed to control the system for stabilizing vertical reactions of the road to the automobile's wheels is considered, depending on the frequency of excitation by the periodic profile. The performed analysis shows that correctly selected regulators reduce the control forces in the control drive, the power required for control, while the result of control, stabilization of the vertical reaction of the road to the wheel, becomes more significant.
Izvestiya MGTU MAMI. 2018;(1):75-82
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Automation of the control of the differential lock in the transmission of a multi-axle wheeled vehicle
Safonov B.A., Kotiev G.O., Smirnov A.A.
Abstract
Due to intensive development of multi-axle wheeled vehicles in the Russian Federation, there is a need to improve its performance characteristics such as flotation, which in turn increases the average speed of traffic in difficult conditions. Increasing the flotation and retain mobility in difficult road conditions is facilitated by intensive management of differential locking clutches. However, for a multi-axle wheeled vehicle, the number of differentials in the transmission makes the task of controlling the locking clutches difficult for the driver. The modern development of microprocessor technology allows the creation of automatic transmission control systems that implement the specified law of switching on and off the differential locking clutches. The method of definition of the law of control of differential locking clutches for a multi-axle wheeled vehicle is shown in the article. The research is carried out with the help of the mathematical simulation model of the curvilinear motion of the vehicle in the Matlab Simulink software package. The law of inclusion of clutches blocking is based on definition of a difference of speeds of rotation of output shafts of a differential and considers various radii of wheels rolling and also an opportunity of reliable switching of differential locking clutch. The sequence of switching on of clutches for locking different differentials in the transmission is determined. The law of deactivation of the differential lock is based on the criterion of maintaining the steering and maneuverability of wheeled vehicle, which contains of admissible increase in the turning radius by 10% in the case of a locked transmission with respect to the turning radius for the differential transmission at the same speeds and steering angles. Numerical simulation is carried out for curvilinear motion along different support surfaces of a wheeled vehicle 8 × 8, in the transmission of which there are 7 differentials. It is established that the creation of a control system based on the proposed law of wheeled vehicles differentials control can be realized without significantly complicating the construction of existing mechanical transmissions by installing additional speed sensors on output shafts of differentials.
Izvestiya MGTU MAMI. 2018;(1):83-90
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Modernization of the cooling system for diesel engines of the YAMZ family with the aim of reducing cavitation damages
Strel'tsov R.V., Vasil'ev V.G., Arabyan A.K., Mamoshin A.I.
Abstract
The article deals with issues related to the modernization of diesel engines to reduce their cavitation damages. During the operation of diesel engines, local fractures can occur, as a rule, the causes of these disruptions can be the vibrations of the walls of cooling cavities of diesel engines, resulting in ruptures of the liquid, which leads to higher pressures, temperatures and potential differences in the cooling sphere. These factors have a destructive effect on the surface of parts, washed with coolant. To maintain a normal thermal regime, it is necessary to remove excess heat from heated parts, that is why the cooling system is designed. One of the promising trends in the development of this system is the increase in the average temperature of the cooling liquid in the water path of internal combustion engines above 100 ° C with a corresponding increase in pressure in the jacket space, which eliminates the boiling of water. As the temperature of the coolant rises, the fraction of heat carried away with the cooler decreases, and the period of self-ignition delay decreases, and the degree of increase in pressure during combustion decreases, which has a positive effect on the operation period of engine parts. Analyzing the reliability of the liquid circuit, it must be taken into account that the efficiency of the pump depends largely on the temperature of the coolant. At a coolant temperature close to the boiling point of the coolant, cavitation phenomena occur, which are manifested in a sharp drop in the productivity of the pump due to the appearance of air and steam bubbles in the liquid. It becomes difficult to ensure the non-cavitation operation of the water pump. Cavitation in the flowing part of the pump often leads to a violation of the circulation of coolant in the circuit and overheating of the diesel. The inclusion of a high-temperature cooling system in the water system of the mixing and supporting device parallel to the water pump is one of the simplest and most effective ways to increase the pump's available cavitation supply.
Izvestiya MGTU MAMI. 2018;(1):91-96
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