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Piston Ring Tribology in Internal Combustion Engines
Orbán, Tomáš ; Maršálek, Ondřej (referee) ; Raffai, Peter (advisor)
The theme of the thesis is tribology of piston rings for internal combustion engines. The work is divided into seven chapters. The first chapter deals with the piston rings, piston rings requirements, describes the main functions of piston rings, types of piston rings, compression rings and oil control rings. Finally, this chapter provides information about the kinematics of piston rings. The second chapter presents the mechanism of friction and lubrication of piston rings, is dedicated to tribology, friction, friction observation history, mechanism of friction and friction suitability. In addition, the work contains information about lubrication, specifically about a lubrication way of internal combustion engines and lubrication regimes. The third chapter deals with hydrodynamic lubrication. The theme of the fourth chapter is boundary lubrication. The fifth chapter provides information about mixed lubrication. Friction in the oil film is the theme of the sixth chapter. Last seventh chapter deals with dry contact friction due to surface roughness contact.
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Reduction of Contact Pairs Friction Losses
Novotný, Marek ; Raffai, Peter (referee) ; Maršálek, Ondřej (advisor)
This bachelor thesis deals with the topic of mechanical efficiency of contact pairs in the crankshaft of the combustion engine. The introductory section focuses on the efficiency of the combustion engine as a whole. In addition, it describes the areas where mechanical losses primarily occur. The following chapters describe mechanism of friction losses, the main factors affecting their amount and the most modern ways to increase mechanical efficiency. In the closing chapter, some basic computing relations, describing the size of mechanical losses are listed. The aim of this thesis is to acquaint the reader with the importance of mechanical efficiency in the area of combustion engines.
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Design of surface texturing experimental rig
Bouma, Adam ; Svoboda, Petr (referee) ; Šamánek, Otakar (advisor)
The aim of this thesis is mechanical indenter design, mainly two basic parts of this apparatus. The introductory section describes the basic techniques of mechanical surface texturing of engineering surfaces. The second part deals with the particular design of the device. It also describes the strength control of loaded components. The economic evaluation is given at the end.
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Effect of lubricant rheology on lubrication film thickness.
Prášilová, Alena ; Šperka, Petr (referee) ; Křupka, Ivan (advisor)
Lubrication is a very important part of mechanical engineering, which ensures high lifetime of machine parts, reduction of friction and wear and also it leads to decreasing of power consumption. In this bachelor`s thesis there is described rheology of newtonian and non-newtonian lubricants and its effect on lubrication film thickness. Measured central film thickness values are compared with theoretical prediction.
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Usage of a high-speed camera for a study of changes of a lubricating film.
Mucha, Roman ; Křupka, Ivan (referee) ; Svoboda, Petr (advisor)
The aim of Bachelor´s thesis is to give an overview of the state of knowledge in the field of usage of a high-speed camera for a study of changes of a lubricating film. The first part desribes the basic terms in the field of high-speed camera. The next part of thesis deals with the history of high-speed cameras and their use in an industry, including study of changes of a lubricating film. Finally, evaluation of current status and further development are included.
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Experimental study of lubricant films in contact of machine parts
Kučera, Ondřej ; Křupka, Ivan (referee) ; Vaverka, Michal (advisor)
This bachelor thesis is focused on the description of methods for experimantal study of lubrication films in contact of machine parts, particularly for non-conformal surfaces, for which elastohydrodynamic and mixed of lubrication is typical. The methods are devided according to measured quantity into the methods for film thickness measurement, contact pressure measurement and temperature measurement. It was described the principle of these methods, the equipment, application and characteristics. Finally, evaluation of current status and further development are included.
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Simulation and Evaluation of the UHMWPE Surface Wear
Franta, L. ; Jeníková, Z. ; Sieber, D. ; Synková, Hana ; Pražák, Josef ; Suchánek, J.
The goal of this research project is to increase the lifetime of total knee joint replacement. Therefore the “In vitro“ simulation of realistic physiological conditions is important. For the knee joint replacement experiments, a KKK ELO 98001 simulator is used. The simulator enables the combination of rolling and sliding motion of replacement components with sinusoidal loading. During the experiment, a considerable amount of wear particles of the UHMWPE component is produced and the friction surfaces are irreversibly changed. Initially, the irregularities of tibia component are smoothed. Consequently, large amounts of UHMWPE wear are released. The surface changes of specimens were evaluated.
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Simulace a vyhodnocování otěrových procesů pro UHMPE elementů náhrady kolenního kloubu
Franta, L. ; Jeníková, Z. ; Sieber, D. ; Synková, Hana ; Pražák, Josef ; Suchánek, J.
The demands on artificial knee joint replacement are steadily increasing. Major motivation of this research project, is to increase the lifetime of present prosthesis designs .The main problem of the commonly used UHMWPE / Steel–Implants is the appearance of polyethylene wear which leads to aseptic loosening and therefore to long-term prosthesis failing. In vitro simulations can be an important instrument to predict the wear behavior of new prosthesis designs and materials. ISO 14243 has been developed to obtain comparable results testing on different in vitro simulators. The aim of this study is to verify, how the simplifications made by the in-vitro simulations influence the simulation results and how today’s prosthesis testing can be made more realistic.
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Friction and lubrication in artificial joints
Vocel, Jan ; Musil, Jan ; Šída, V.
The changes in function of artificial joint could be caused also by inconvenietn lubricant. At present time besides ionic fluids also some water soluble polymers and their derivatives have been investigated. Friction measurements using a technical frictional machine showed low coeficient of friction with negligible wear.
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