Перегляд за Автор "Karpenko, Volodymyr"

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Indirect assessment of the rolling resistance of a car tire in the starting mode of motion
(Харківський національний автомобільно-дорожній університет, 2022) Karpenko, Volodymyr; Voropay, Oleksiy; Neskreba, Eduard; Карпенко, Володимир Олександрович; Воропай, Олексій Валерійович; Нескреба, Едуард Євгенійович
Problem. On the condition of the tires and their correct choice depending on the weather conditions, first of all, the indicators of many operational properties of the car depend. The internal pressure and temperature of the tire increases during driving, as a result, there is a significant effect on the rolling resistance of the tire. At high values of the rolling resistance coefficient, first of all, fuel consumption increases, tire wear increases, etc. It is important to know how the rolling resistance coefficient changes during the starting period of motion. Goal. The purpose of this work is to determine the starting mode of motion time for specific vehicles. Based on the obtained dependences of the internal pressure and temperature of the tire on time, it is necessary to evaluate how the rolling resistance coefficient changes. Methodology. As a result of experimental studies, on vehicles equipped with tires of various sizes and seasonality, the dependences of the pressure and temperature of the tire material at three points (tread zone, shoulder part and sidewall) were obtained. Using the results of the experiment, as well as based on the dependencies presented in scientific papers devoted to the study of the performance characteristics of car tires, an indirect assessment of the rolling resistance coefficient when driving in the starting mode is made. Results. The value of the increase in the internal pressure of the gas filler in the tire has been established and the driving time for the studied vehicles in the starting mode has been determined. The most intense temperature rise is observed in the shoulder area of the tires. The temperature of the surface layer of winter tires increases less than summer tires, and, accordingly, driving on winter tires is safer at temperatures close to 0°C and below. Originality. A technique for indirectly assessing the rolling resistance of a car tire when driving in the starting mode (on "cold" tires) is presented, that is, knowing how the internal air pressure and tire temperature change, it is possible to predict a change in the rolling resistance coefficient. Practical value. Using the dependences obtained as a result of an indirect assessment of the rolling resistance of car tires, one can judge the value of the rolling resistance coefficient without resorting to experiments. The well-known assertion that it is necessary to timely replace summer tires with winter ones (when the ambient temperature can reach +5 ° C and lower) is confirmed, thereby significantly improving road safety.
Refined assessment of tire rolling resistance in the starting mode
(Харківський національний автомобільно-дорожній університет, 2022) Karpenko, Volodymyr; Neskreba, Eduard; Карпенко, Володимир Олександрович; Нескреба, Едуард Євгенійович
Rolling resistance is one of the most important operational characteristics of a car tire. First of all, the fuel consumption, durability and service life of the tire depend on the rolling resistance. Of course, the higher the rolling resistance, the faster and more intensively the tire will wear out. Also, car braking parameters, such as deceleration and, accordingly, the braking distance, may indirectly depend on the rolling resistance characteristics. In turn, rolling resistance is influenced by the properties of the tire itself, as well as the condition of the road surface and weather conditions. It is especially important to evaluate the operational characteristics of a car tire in the starting period of movement, because at this time the behaviour of the tire is unpredictable. Goal. The purpose of this work is to improve the methodology for evaluating the rolling resistance of a car tire in the starting period of movement. Knowing how the rolling resistance changes during the starting movement, it is possible to evaluate the operational properties of the car. Methodology. Refined assessment is carried out with the help of dependencies obtained in previous scientific works. But in order for the result of the rolling resistance assessment to be correct, it is necessary to determine the necessary characteristics of the tire. Namely, we are talking about the characteristics of radial stiffness. In the work, these characteristics are determined both by conducting experimental studies and by using FEM. Results. Thanks to the conducted research, significant results were obtained on the change in rolling resistance during the starting motion. It was established that with an increase in internal pressure from 0.17 MPa to 0.225 MPa, as a result of the starting motion, the rolling resistance decreases by approximately 20-25%. Originality. From the analysis of the literature, it can be concluded that in most of the studied works, the peculiarities of the interaction of automobile tires with the supporting surface in the starting period are not taken into account during various studies. It can be said that the originality of this work, on the one hand, is that the rolling resistance is investigated during the starting motion, and on the other hand, that its assessment is carried out both on the basis of the results of experimental studies and with the help of FEM. Practical value. In this work, it is possible to highlight the obtained results, thanks to which we can estimate the rolling resistance of a car tire with sufficient accuracy. The methods of determining the operational characteristics of a car tire, presented in the work, can be used during its operation and at the design stage.
Дослідження закономірностей часу простою маршрутних транспортних засобів під час посадки та висадки пасажирів
(Харківський національний автомобільно-дорожній університет, 2021) Свічинська, О. В.; Карпенко, В. О.; Svichynska, Olha; Karpenko, Volodymyr
У статті представлено результати дослідження часу простою маршрутних транспортних засобів на зупинках під час посадки та висадки пасажира. Отримано закономірності розподілу даної величини на реально зібраних даних для автобусів та тролейбусів м. Харків. Перевірено похибку розрахунку пасажиропотоків у випадку врахування часу простою на аналітичній моделі маршрутної мережі.