Перегляд за Автор "Holenko, K."

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  • Ескіз
    Документ
    Modeling of contact stresses and evaluation of wear life of a valve mechanism guide with lubricating grooves
    (Хмельницький національний університет, 2024) Holenko, K.; Vychavka, A.; Dykha, M.; Dytyniuk, V.
    Valve guides are crucial for maintaining proper alignment, positioning, and valve stem clearance as it moves in the cylinder head. Valve bushings are subjected to load and sliding friction; with excessive wear of the guides, the engine begins to consume oil and the valve mechanism becomes noisy. This paper proposes the use of a special knurling to restore and increase the wear resistance of guide bushings. The profile tool is designed to restore valve guides by rolling a spiral groove on the inner surface of the sleeve. After applying this technology, a spiral oil-retaining profile remains on the surface of the sleeve bore. . Using the Solid model, the effect of changing the geometry of the guide bore by the lubricating grooves on the maximum and average stress indices in the guide-valve contact was analyzed. It was found that the maximum stresses of the model with grooves are lower than those of the model with a smooth guide surface. Based on the finite element model, the durability of the valve-guide pair with oil-retaining grooves was analyzed and it was determined how many cycles the contact surface of the guide can withstand. It was established that by reducing the contact pressure, the actual resource of the guide with grooves increased.
  • Ескіз
    Документ
    Simulation model of contact interaction during surface strengthening of steel parts
    (Khmelnytskyi National University, 2023) Holenko, K.; Dytyniuk, V.; Dykha, M.
    In the processes of surface strengthening of steel parts, the stress-strain state is decisive for explaining the physical processes of strengthening, forming the dimensions of the contact area. Analytical dependences of contact parameters are quite approximate. In this work, based on the Ansys software complex, a simulated model of the contact of a truncated torus with a cylinder is proposed, which demonstrates the kinetics of the process of pressing a hard alloy tool into a steel workpiece - a cylinder. The experiment was conducted for 4 seconds in order to determine the maximum level of stresses, the distribution of stresses and the amount of residual stresses after removing the load. The clamping force was applied mainly in the zone of elastic deformations. The results showed an uneven stress distribution with a maximum in the center of the contact spot of 1082 MPa. After changing the load direction, small residual deformations at the level of 0.00311 μm were observed in the center of the contact patch. This indicates a violation of the elastic region on a small contact area, which does not affect the general nature of the stress distribution and can be removed during the finishing process. The results of simulation of the stressed state are used for the correlation with the observed structural changes of the material during the action of thermal and power stresses. The stress peak was formed at a distance of 200 μm, which contributes to the formation of maximum values of microhardness at this depth.
  • Ескіз
    Документ
    Thermal comfort formation of the bus interiordepending on the power unit layout
    (Хмельницький національний університет, 2022) Holenko, K.; Voichyshyn, Y.; Horbai, O.; Burian, M.; Popovych, V.; Makovkin, O.; Голенко, К.Е.; Войчишин, Ю.В.; Горбай, О.З.; Бур’ян, М.В.; Попович, В.В .; Маковкін, О.М.
    Energy consumption and thermal comfort are among the issues that research engineers of heating, ventilation and air conditioning systems deal with when investigating the most feasible solutions for their implementation. Existing methods of thermal comfort assessment are not optimized in two important and interrelated aspects: achieving thermal comfort(a) at the lowest possible energy consumption(b). Thermal comfort is situationally achieved when occupants perceive the ambient temperature, humidity, air movement and thermal radiation as ideal and do not prefer warmer or colder air or a different humidity level. Thermal comfort is defined by ASHRAE Standard 55 as a subjective concept characterized by the sum of sensations that create physical and mental well-being in a person. That is, he /she is in a state in which he/she feels comfortable and does not need to change one or more environmental parameters. Many studies have been conducted according to the international standards for thermal comfort in vehicles. The presence of a large number of people in the bus leads to a deterioration of the air quality in its interior. The loss of quality is mainly caused by gases resulting from breathing and other organic particles. The presence of moisture, combustion products, particles can also reduce the air quality in the interior. Air quality is affected by the design features of heating, ventilation and air conditioning systems, which largely depend on the location of the power unit, which is the subject of the research. The influence of the bus enginelayout is analysed in the presented work: for the rear- engine layout, the location of the engine vertically in the interior and other cases are also considered. Special fans are installed in the engine compartment to remove heat emitted by the engine.
  • Ескіз
    Документ
    Підвищення антифрикційних характеристик поршневих ущільнень компресора кондиціонера автомобіля
    (Хмельницький національний університет, 2024) Диха, О.; Свідерський, В.; Голенко, К.; Dykha, O.; Svidersrkyi, V.; Holenko, K.
    Проаналізовано недоліки, що мають місце при застосуванні фторполімерів у вузлі тертя поршневе ущільнення – циліндр компресора кондиціонера автомобіля. Розглянуті перспективні методи модифікації політетрафторетилену і вимоги до його наповнювачів. Проведені експериментальні дослідження підтвердили переваги антифрикційних композиційних фторопластових матеріалів модифікованих комбінованими наповнювачами: вуглецевим і скловолокном, вуглецевим волокном і порошком закису міді або свинцю для вузла тертя поршневе ущільнення – циліндр компресора кондиціонера автомобіля.