Випуск 48 / Выпуск 48

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ЗАГАЛЬНІ ВІДОМОСТІ ПРО ЖУРНАЛ
(Харківський національний автомобільно-дорожній університет, 2021)
Electrical power unit of the transformer oil centrifugal cleaning unit
(Харківський національний автомобільно-дорожній університет, 2021) Hnatov, A. V.; Arhun, Shch.; Bagach, R. V.; Nechaus, A. O.; Tarasova, V. V.; Ruchka, O. O.; Don, A. V.; Patlins, A.; Гнатов, А. В.; Аргун, Щ. В.; Багач, Р. В.; Нечаус, А. О.; Тарасова, В. В.; Ручка, О. О.; Дон, А. В.; Патлінс, A.
Problem. Cleaning transformer oil is one of the important engineering tasks, whose solution is associated with significant material and energy expenditure. Due to the increase in electricity consumption at modern automobile companies (firms, organizations, service stations, etc.), the load on transformer substations increases and the requirements for reliability of electrical and electronic devices become more complicated. This, in turn, leads to the problem of cleaning and recycling of transformer oil. Goal. The goal is the research and development of an efficient unit for centrifugal cleaning of transformer oil with a drive control system that provides automation of the start and braking mode of the drive. Methodology. Analytical methods of research, methods of the theory of electric machines and electric drives are used, as well as the methods of calculating electric circuits. Also, methods of analysis of circuits and control of power electronics devices, principles of operation and methods of control of static converters are used. Results. The structural scheme of the unit for cleaning transformer oil is developed. The calculations of the main elements of the power block of the transformer oil cleaning unit are performed. The block diagram of the voltage converter with frequency f = 50 Hz to alternating voltage with frequency f = 400 Hz is developed. Control circuits of the electric drive of the centrifugal separator are chosen. The analysis of operation of electric drive control circuits is carried out and the principles of their work concerning two components are considered: the regulated rectifier and the inverter. Originality. The scheme of the converter of alternating three-phase current with voltage of 220 V and frequency of 50 Hz, into alternating three-phase current with voltage of 220 V and frequency of 400 Hz is developed. This frequency, in addition to providing the necessary characteristics of the oil separator, allows you to develop a converter device of a relatively small weight and volume, and also provides its high reliability. Practical value. Utilizing the used transformer oil in this way will solve several problems at once. It is possible to reduce the initial production of transformer oil. The issue of waste oil disposal is being resolved leading to the solution of the environmental aspect of this problem. All this will reduce the cost of oil poured into transformers and the operating cost of transformer substations.
Measuring the soil compaction zone and pressure of deformed soil on underground objects with an asymmetric cylindrical tip
(Харківський національний автомобільно-дорожній університет, 2021) Suponyev, V. M.; Fidrovska, N. M.; Balesnyi, S. P.; Ragulin, V. M.; Kravets, S. V.; Супонєв, В. М.; Фідровська, Н. М.; Балесний, С. П.; Рагулін, В. М.; Кравець, С. В.
At trenchless laying of engineering communications in soil the method of static puncture has received wide application at formation of a well. Power plants that implement it have small di-mensions, which make them more effective in laying distribution engineering networks in tight urban conditions. Problem. The main disadvantages of the method are the low accuracy of the trajectory and the significant stress in the soil after its compaction, which can lead to the de-struction of adjacent underground objects. The first disadvantage is solved by controlling the trajectory of the soil-piercing working body. To solve the second question, it is necessary to know and take into account the specifics of the formation of communication cavities in the soil with an asymmetric tip, which is used for this purpose. Goal. The aim of the work is to establish the regularity of the process of soil puncture by the soil-piercing working body with an asym-metric tip in the form of a cylinder cut at an angle. Methodology. The approaches adopted in the work to solve this goal are based on the theories of deep soil cutting, scientific foundations of soil mechanics, their normative physical and mechanical properties and the law of conserva-tion of soil mass before and after compaction. Results. The calculated dependences for deter-mining the size of the destructive zone from the elastic-plastic deformation of the soil during its puncture by an asymmetric tip with a frontal surface in the form of a beveled cylinder and the pressure of the deformed soil on underground objects are obtained. It is established that the maximum size of the destruction zone and its pressure on underground objects will occur in sol-id sand. With a tip diameter of 0.3 m, their values can reach 5 m and 0.245 MPa, respectively. Originality. The obtained regularities of soil puncture by a working body with an asymmetric tip in the form of a beveled cylinder made it possible to get an idea of the influence of its deformed state on adjacent communications depending on geometric parameters of the tip and physical and mechanical properties of soils. Practical value. The obtained results can be recommended in the design and determination of technological capabilities of installations for static soil punc-ture.
Influence of the measuring tools on the flow characteristics in vortex chamber pump
(Харківський національний автомобільно-дорожній університет, 2021) Rogovyi, A. S.; Neskorozhenyi, A. O.; Роговий, А. С.; Нескорожений, А. О.
Problem. Perturbation of the flow by measuring instruments forces researchers to choose optical research methods. But these methods significantly increase the cost of experimental research, due to the high cost of optical-type measuring equipment. On the other hand, using contact methods for measuring the flow velocity, such as Pitot tubes, hot-wire anemometers, the researcher must be sure that the measurement results can really be compared with the calculations results and the equipment influence on the flow parameters is minimal. The aim of this work is to study the measuring tool influence on the flow characteristics in the swirl chamber pump, as well as to compare the results obtained due to the measurements with the parameters of the undisturbed flow. The research methodology consisted of two stages: 1) modeling the flow in the model pump; 2) comparison of flow characteristics, as well as the values of velocity and pressure at the points of installation of the measuring tool. Results. Although the total velocity at the measuring point is practically independent of the measuring tool, the tangential component of the velocity is significantly reduced. It indicates that there is a significant error in velocity measuring. For a more accurate rotational velocity component measurement, it is necessary to orient the instrument perpendicular to the measured component. Scientific novelty. Installing the measuring tool in the end cover of the swirl chamber reduces the flow rate sucked by the pump through the lower axial channel. The size of the tool has practically no effect on the energy characteristics of the swirl chamber pump. Practical value. To ensure measurement accuracy, the ratio of the swirl chamber dimensions and the tool should be ensured in the way that the relative diameter of the tool does not exceed 0.25 of the swirl chamber neck diameter.
Justification of the choice of public transport service type on the route
(Харківський національний автомобільно-дорожній університет, 2021) Skirkouski, S. V.; Sedziukevich, U. M.; Svichynska, O. V.; Скірковський, С. В.; Седюкевич, В. М.; Свічинська, О. В.
Problem. Currently, there exist two main types of service on public transport routes – headway-based and timetable-based. They differ by the frequency of service at the stops and by the information available for passengers. The required frequency of service significantly affects transport operator costs and passenger travel time which, in turn, influences the cost for a passenger. One of the ways to reduce costs for both parties of the transportation process is to make a reasonable choice of the type of service or switch between the types during the day depending on the passenger flow volume. Goal. In the paper, to justify the choice of between the types of service, the cost of public transport vehicles operation and the losses of passenger travel times are taken into account. Methodology. The developed way of making a choice about the type of service allows increasing the efficiency of urban public transport due to reducing the passenger waiting time by switching from the headway-based service in rush hours to timetable-based service in the periods of passenger flow volume decline. Results. The relationship allowing making a decision about the type of service on the route is developed. It allows to correctly introduce the type of service which will ensure the balance between the transport operator and passenger costs. Originality. The developed approach to make a decision on the type of service allows reducing the passenger waiting time by switching from headway-based service in rush hours to the timetable-based service in the periods of decline in passenger flow volume during the day. Practical value. The results of the research based on the survey data allowed estimating the numerical value of the headway at which it is expedient to switch to the timetable-based service.
Comparative analysis of methods for determination of supply flows
(Харківський національний автомобільно-дорожній університет, 2021) Semchenko, N. О.; Kholodova, O. О.; Buhaiova, M. О.; Семченко, Н. О.; Холодова, О. О.; Бугайова, М. О.
Problem. The capacity of signalized intersections is determined using the concept of "saturation flow". It is the main characteristic in the process of their analysis, design and calculation. The work is devoted to solving the scientific-applied problem of increasing the efficiency of the signalized intersection at one level by choosing a rational method of determining saturation flows for these characteristics of traffic flows, geometric parameters of the intersection and infrastructure in its area. The subject of the study is the influence of the main characteristics of the traffic flow, parameters and infrastructure of the intersection on the saturation flow value. Goal. The aim of the work is the analysis of the influence of the main characteristics of the traffic flow, parameters and infrastructure of the intersection on the saturation flow value. Methodology. The calculation of the control regime at the intersection is based on determining the relation between the traffic intensity of vehicles at the intersection and the saturation flow value, which changes under the influence of a number of factors. Analytical calculation of the saturation flow value is based on using of correction factors that take into account the influence of these factors. Results. The methods of determination of saturation flows are analyzed out in the work; performed a comparative analysis of the definition of ideal saturation flows by different methods; a comparative analysis of the determination of the saturation flow correction coefficients for the parameters that have an effect on it were performed; the estimation of discrepancy at calculations of coefficients of correction of saturation flows by various methods is done; the list of coefficients which need to be considered at definition of their influence on a saturation flow is refined. Originality. In oppose to classical and other approaches to determining the saturation flow, the method recommended by the American "Highway Capacity Manual" takes into account more parameters of influence. It is proposed to use this method for the saturation flow calculation, but with an updated list of coefficients that must be taken into account in the calculations. Practical value. The results of the work can be used in the practice of improving the efficiency of signalized intersections in sections of the urban road network, as well as in further research on this topic.
Comparative forecast of passenger transportation in long haul railway and long-distance bus service
(Харківський національний автомобільно-дорожній університет, 2021) Balaka, Ye. I.; Rezunenko, M. Ye.; Vdovychenko, V. O.; Балака, Є. І.; Резуненко, М. Є.; Вдовиченко, В. О.
Problem. The article presents methodological approaches to determining the volume of passen-ger service in long-distance railway connections and intercity bus services in Ukraine, which are expected in the coming years. Goal. The purpose of the study is to increase the reliability of the information base for making informed management decisions on the further development of the transport passenger complex. Methodology. In the process of research there was used a set of methods of expert assessment and logical analysis of possible factors influencing; economic and mathematical modeling; formalized extrapolation methods to determine the predictive pa-rameters of influencing factors. Results. The forecast values of the number of transported pas-sengers and the values of passenger turnover in long-distance railway and intercity bus connec-tions in the short-term period are obtained. Originality. To estimate the forecast values of pas-senger traffic there was used the combination of methods of correlation-regression analysis and forecasting the magnitude of factors by the method of variable average. Practical value. The study of the patterns of passenger traffic dynamics revealed that in the next two years no signifi-cant changes are expected in the volume of work of both kinds of transport. However, in long-distance railway transport it is possible to increase passenger traffic by 1.6 % (0.74 million pas-sengers) and, accordingly, the annual passenger turnover will increase by 2.2 %. In the inter-city bus service, a slight decrease in the volume of passenger traffic by 0.8 % (0.93 million pas-sengers) is possible, and the rate of decrease in annual passenger turnover will be 0.5 %. In the conditions of constant reduction of the population of Ukraine the most effective mechanism of ensuring further sustainable development of both types of passenger transportation is constant adjustment of tariff policy on the principles of flexibility and bonus tariff formation under condi-tion of continuous improvement of services quality.
Research of the factors influencing the operational performance of urban public transport
(Харківський національний автомобільно-дорожній університет, 2021) Skirkouski, S.; Sedziukevich, U.; Karpenko, V.; Svichynskyi, S.; Скірковський, С. В.; Седюкевич, В. М.; Карпенко, В. О.; Свічинський, С. В.
Problem. Currently, there is no universal approach to improve the efficiency of the urban public transport operation. Different methods are used during the estimation of public transport operation cost and the quality of services for the passengers. It makes actual the development of the target function which will allow assessing the carrier cost and passenger expenditures, and therefore find the balance between the interests of these parties of the transportation process. Thus, the alternative to the existing approaches can be created and then used to organize passenger transportation and improve transport enterprise management. Development of this alternative is the actual task as the new target function will open the horizon to improve the methods of organization of public transport operation. Goal. The new approach to optimize the costs of public transport operation needs to be tested for the appropriateness for the planning of passenger service in cities. Methodology. The developed target function was derived as the result of the analysis of the economic and social factors influencing the efficiency of the urban public transport operation. Results. The use of the developed target function allows finding the optimal values of cost components for the passenger and the carrier. Originality. The obtained function to optimize the performance of public transport allows reducing the costs of suboptimal use of vehicles capacity, suboptimal allocation of the vehicles to the routes and the irrational organization of vehicles operating on the routes. Practical value. The results of the research clarify the controlled and uncontrolled parameters of the public transport system operation.
Determining the starting time of car movement to stabilize the internal pressure and the temperature in the tires
(Харківський національний автомобільно-дорожній університет, 2021) Karpenko, V. O.; Kaps’kyy, D. V.; Rudenko, N. V.; Neskreba, E. Ye.; Карпенко, В. О.; Капський, Д. В.; Руденко, Н. В.; Нескреба, Е. Є.
Problem. The problem of road safety does not lose its relevance in our time. The condition and performance of tires has a significant impact on the safety of road transport. Unfortunately, the tire pressure monitoring requirements of the developers are not always met. Naturally, now some modern cars are equipped with various systems for monitoring and even adjusting the internal tire pressure. However, there are relatively short periods of time during which the pressure and temperature in the tire change dramatically, and hence its other performance and properties. First of all, we are talking about dramatically changing weather conditions and the starting movement of the car. And then additional monitoring of tire pressure is needed. Goal. On the basis of the experimental studies carried out, to obtain the dependence of the tempera-ture and pressure changes inside the tire on the time of car movement. To determine the initial period of time of car movement until the pressure and temperature in the tested tires stabilize. Methodology. The work used the technique of both bench tests of tires in the laboratory and road tests under real weather conditions by car. Based on the numerical processing of the ex-perimental results, dependencies were obtained, using which it is possible to determine the in-crease in temperature and pressure in tires in the mode of starting movement of the car. Results. The analysis of scientific publications on this topic is performed. The time from the beginning of the car to the stabilization of temperature and internal pressure in the tires is determined, as well as the increase in temperature and pressure inside the tire during this period. The method of determining the starting time of the car to stabilize the internal pressure and temperature is proposed. Originality. In this work, for the first time, a method is proposed for assessing the temperature and internal pressure in tires in the mode of starting movement of the car, which makes it possible to obtain dependencies without resorting to further experimental studies. Prac-tical value. Using the obtained dependencies for certain tires and under different weather condi-tions, it is possible to predict the change in tire pressure at the starting mode of the car's movement, and therefore make adjustments to this value, if necessary, which will have a positive effect on the safety of moving vehicles.
Features of adaptive brake control of the secondary brake system of a multi-axle vehicle
(Харківський національний автомобільно-дорожній університет, 2021) Bogomolov, V. O.; Klimenko, V. I.; Leontiev, D. M.; Kuripka, O. V.; Frolov, A. A.; Don, E. Yu.; Богомолов, В. О.; Клименко, В. І.; Леонтьєв, Д. М.; Куріпка, О. В.; Фролов, А. А.; Дон, Є. Ю.
Problem. Malfunction of the service braking system of a wheeled vehicle (WV) significantly affects road safety, especially when operating multi-axle vehicles with big masses. One of the ways to increase the level of road safety of multi-axle vehicles, when braking using a spare (emergency) braking system, is the introduction of automated adaptive braking systems into the design of the brake drive of vehicles. The definition of the limits of using the adaptive braking system on vehicles with many axles is almost not disclosed in the scientific and technical literature, therefore, the issue of using such a system on vehicles with a large number of axles requires additional research. Purpose. The purpose of this work is to develop a simulation model for adaptive control of the braking process of a multi-axle vehicle using a spare (emergency) braking system, taking into account the simulation of the dynamics of the drive and the variability of the adhesion properties between the tire of the vehicle wheel and the road surface. Methodology. To achieve this goal, it is necessary to develop a simulation model of the brake drive in an adaptive mode, implement a model of the interaction of the tire with the road surface, and implement a model of the braking dynamics of a multi-axle vehicle in the event of a malfunction of its service brake system. Originality. The proposed key criterion (Kr) for changing the throttle section in electro-pneumatic pressure modulators, which provide adaptive air inlet or outlet from the corresponding brake chambers of the drive, during simulation, made it possible to simulate the operation of the drive circuits in the adaptive mode. It has been established that, depending on the potential for the realization of the adhesion between the tires of automobile wheels and the road surface, the pressure in the electro-pneumatic brake drive with its adaptive regulation can be increased by no more than 0.04 MPa.
The concept of the clutch control law of a car
(Харківський національний автомобільно-дорожній університет, 2021) Mykhalevych, M. H.; Fandieieva, A. Ye.; Михалевич, М. Г.; Фандєєва, А. Є.
Problem. The combination of comfortable automatic control of the car's transmission and at the same time preservation of high indicators of energy efficiency and cost of a design is possible by use of automatic mechanical transmission. The automatic clutch control system plays a significant role in providing comfort in such transmissions. The laws of controlling it are not perfect today. Goal. The aim of the work is to create a clear concept of the law of clutch control, which is easy to implement in a microcontroller and is well adapted to adapt to different driving conditions. Methodology. Graphically, the concept of the perspective law of clutch control is formed by two Bezier curves. One of the curves acts as a guide, and the other forms the surface of the law. Results. On the basis of the Bézier curves of the third degree the concept of the law is formed and the connection of the reference points of the Bézier curves with the physical parame-ters of the working process of vehicle movement is substantiated. Originality. The formation of the Bézier curve, which is decisive for the concept of the law, is formed on the basis of a typical working process of synchronization of the angular velocity of the clutch discs during the movement of the vehicle. In contrast to the laws of clutch control considered in the scientific litera-ture, the proposed concept provides for clutch control outside the site of the synchronization process and ensures the avoidance of jerks during further acceleration. Practical value. The proposed algorithm provides full engagement of the clutch only after full synchronization of the clutch discs. The formation of a special form of the law in the form of a curve tangent to the abscissa axis reduces the jerks when closing the clutch discs.
The method of expert assessment of the technical condition of an automobile engine after overheating
(Харківський національний автомобільно-дорожній університет, 2021) Khrulev, A. E.; Saraiev, O. V.; Хрулєв, О. Е.; Сараєв, О. В.
Problem. For expert studies of the technical condition of a car, a difficult task is to determine the causes and development of malfunction of engine mechanisms and systems. The paper proposes a model of engine malfunction during overheating, including in emergency mode caused by rapid loss of coolant. It has been established that thermal damage to the cylinder head is possible within 10 seconds after the cooling failure. The piston heats up more slowly and can only be damaged in the upper part and for a much longer time. According to the results of the study, it was found that in the event of an emergency loss of coolant, the driver does not have the technical ability to see the temperature rise, which may be important when investigating the causes of engine malfunctions associated with overheating. Goal. The goal is to investigate and reproduce the model of engine failure after overheating. Methodology. The theoretical calculated data are confirmed by real experimental studies of engine overheating failures. Results. It was calculated by calculation that in the absence of coolant, the temperature sensor, if it is located on the outlet pipe of the cylinder head, will not increase the temperature until the engine fails. A certain definite character of malfunction of parts of engine mechanisms during its sudden overheating is shown. Originality. On the basis of the developed models, a methodology was drawn up and the calculation of the thermal state of engine parts after overheating was performed. Practical value. The research carried out and the computational models compiled allow the expert to make a more objective assessment of the development of the engine malfunction mechanism when it overheats during the operation of the car.

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