Temperature operating modes and energy intensity of a bus clutch under urban driving conditions.
Students Name: Fedorchak Oleh Mykhailovych
Qualification Level: magister
Speciality: Motor Vehicle Transport
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2025-2026 н.р.
Language of Defence: ukrainian
Abstract: The friction clutch (FC) serves to reliably transmit torque from the engine to the transmission, as well as to briefly disconnect them for the purpose of shifting gears and subsequent smooth acceleration of the car. In addition, it protects the transmission and engine from excessive overloads during sharp changes in the machine’s driving mode. High reliability of FC determines the minimum amount of costs (work) for its maintenance during operation. Reliability of FC depends on the quality of their manufacture, design features, operating conditions. Versatile and diverse studies show [1] that the limited resource of FC is due to the fact that their calculations and design are carried out without detailed consideration of interdependent dynamic, thermal and frictional processes that occur on friction pairs (FP) of FC. The object of the study is the thermal processes in the friction clutch of the bus "ATAMAN" A092N6 in urban operation mode. The subject of the study is the temperature dependence of automobile clutch elements on the time of its operation in urban operating conditions. The purpose of the work is to investigate the temperature regime and energy consumption of an automobile clutch in urban operating conditions. The first section considers the main types of wear during the operation of friction pairs of friction units. The main attention is focused on the nature of mechanical-chemical and abrasive wear [2]. In section 2, a classical transmission scheme is analyzed, which includes a friction clutch (FC) and a stepped gearbox. Two states of the FC and modern requirements for them are analyzed. Statistical data on the probability of failure of FC elements for various types of motor vehicles (MVs) are presented. The criteria for the specific load of the FC and the dynamics of their growth are determined, which has increased by 1.6 times over the past 50 years, and their durability has increased by 3–4 times. This indicates a significant improvement in the designs of the FC and the materials of their elements. It is found that the operation of the FC must meet certain requirements [3], including environmental protection. Therefore, in section 1, a classification of clutches is carried out according to the methods of transmitting engine torque and their control. Typical clutches of cars with springs both on the periphery and in the central part of the pressure plate are analyzed. It is noted that the clutches with peripheral springs are switched off, depending on the size, by 3–6 steel forged or stamped levers with cyanidation and subsequent hardening. In order to ensure frictional properties, the clutch drive discs and flywheels are made of gray cast iron and further normalized. Clutch pressure plates must meet the requirements of rigidity, wear resistance and strength, as well as good workmanship. The conditions for smooth and quick clutch engagement are considered, for which graphical dependencies are given. It is noted that the responsible part of the clutch is the driven steel discs with a friction lining. Known connections of linings with a disk - holder (riveted, glued and molded) are considered. It is emphasized that clutch linings are currently made of composite materials [2]. For this purpose, powder metallurgy and elastomer processing technologies are involved. As an example, the properties of sintered materials (based on iron, copper, etc.) of linings in terms of thermophysical and strength parameters are given. The technology of their manufacture is considered and their comparative characteristics are considered. It is stated that for smooth switching on of the FC, the clutch torque must exceed the engine, that is, the reserve factor must be greater than unity. For this purpose, the diagrams of changes in this coefficient from many factors are analyzed and the modes of switching on the FC (sharp and smooth) and the corresponding analysis of the course of their characteristics are considered. The method of calculating the work of slipping of the FC is considered. Section 3 is devoted to the mathematical description of the processes of heating - cooling of the FC elements. It is noted that the analytical solution of the differential equation of heat conductivity with complex and variable boundary conditions for bodies of complex shape, as in the FC and fast-moving processes in them, does not currently exist. Therefore, for this purpose, a grid model of the clutch was created in Section 4. The use of the software package “Fourier – 2 x,y,z” [4] allowed us to study the temperature fields of the clutch elements and the change in the thermal state of the bus clutch during the SAE J1073-201210 tests [4] and to determine its energy consumption. The latter turned out to be sufficient, since the clutch elements do not reach critical temperature values that would cause a change in their physical and mechanical properties. Keywords: friction clutches, skidding work, bus, mesh model, software package “Fourier – 2 x,y,z”. List of used literary sources 1. Klymenko V.I. Teoretychni osnovy stvorennia ta vdoskonalennia pnevmatychnykh aparativ halmivnoho keruvannia, pidvisky ta zcheplennia avtotransportnykh zasobiv: avtoref. dys…dokt. tekhn. nauk: 05.22.02-avtomobili ta traktory / V. I. Klymenko / KhNADU.- Kharkiv, 2018.-40 s. 2. Volchenko O.I. Trybolohiia: Pidruchnyk dlia VNZ / O.I.Volchenko, M.V.Kindrachuk ta in.-Ivano-Frakivsk: Vyd-vo Prykarpatskoho nats. un-tu im. V. Stefanyka, 2015.- 372 s. 3. SAE J1073-201210. Spring-Loaded Clutch Friction Test Procedure (STABILIZED Oct 2012). SAE International/ SAE IC Powertrain Steering Committee, 2012. – 3 p. 4. Hudz H.S. Rozpodil teplovykh potokiv v elementakh dyskovykh halm avtomobiliv: monohrafiia / H.S.Hudz, M.V.Hlobchak, M.M.Ostashuk. - Lviv: KINPATRI LTD, 2014. - 110 s