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Influence of fuel additives for passenger cars
Obytová, Eliška ; Bradáč, Albert (referee) ; Bilík, Martin (advisor)
This diploma thesis deals with the addition of automotive fuels and their effects. The aim was to evaluate the function and efficiency of fuel additives present in the fuel at gas stations, and subsequently to improve the fuels accordingly by adding additional individual chemical compounds. The theoretical part explains the concepts, functions and processes related to fuel additives and the basics of tribotechnology. The practical part deals with the process of testing the properties of fuels, their functions, additional additives and its impact for practical use.
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The effect of surface grooves on point contacts lubrication
Matoušek, Kamil ; Čermák, Jan (referee) ; Šperka, Petr (advisor)
This diploma thesis deals with experimental study of the effect of surface grooves on distribution of lubricant film in elastohydrodynamic lubricated point contact. Lubricant film thickness was measured by ball-on-disc apparatus using an optical interferometry technique - thin film colorimetric interferometry. The effects of groove geometry, lubricant and operating conditions were studied in this diploma thesis. The effects of these variables are evaluated based on newly suggested parameter Rgi (groove influence ratio). Groove influence ratio is defined as an influenced film thickness influenced by groove divided by film thickness for smooth surfaces.
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Design and execution of additional module of laboratory equipment for measurement of friction within lubricated contacts
Stifter, Jan ; Šperka, Petr (referee) ; Frýza, Josef (advisor)
This bachelor‘s thesis presents the design and implementation of a module of laboratory device for measuring coefficient of friction and friction forces in elastohydrodynamic lubricated contacts. The module is able to measure friction forces in two perpendicular axes. A motivation for realization of this module was the absence of a similar equipment. The retrieval section of this thesis is dedicated to tribology, strain gauges (force sensors) and compliant mechanisms. The selection of the appropriate concept of the module and the force transducers is solved in the design part of thesis. The compliant mechanism with flexure hinges was designed via FEM analysis. This mechanism allows the displacement of the contact member of module in the direction of the frictional forces acting within a lubricated contact. The proposed module was manufactured, implemented in laboratory equipment and its functionality was tested. According to preliminary results, the module fulfilled the objectives of this thesis.
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Nanolubricants for practical applications
Sochor, Ondřej ; Frýza, Josef (referee) ; Svoboda, Petr (advisor)
This bachelor thesis is concerned with describing nanolubricants and enhancing their characteristics using suitable additives, such as nanoparticles. These can improve their tribological properties and reduce mechanical wear and friction between two surfaces. This thesis summarizes manufacturing, some features and mechanisms that apply to nanoparticles and nanolubricants. The main outcome of the work is a synthesis of acquired knowledge in the field of nanolubricants for the purpose of practical application and description of current trends in its research as being used as additives.
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Lubricants created by nature
Drobilič, Ivo ; Urban, Filip (referee) ; Nečas, David (advisor)
This bachelor thesis provides an overview of substances which can be considered as the lubricants in its natural environment. The first part of the thesis of focused on lubricants in human body. The substances such as water, blood or synovial fluid are analysed in a detail. The following chapter deals with lubricants in everyday life. As the example, decrease of tyre adhesion in case of rain or longer breaking distance of trains as a consequence of presence of leafs on rails, can be mentioned. The last part, in addition, summarizes the lubricants which are based on natural products.
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Radial Slide Bearing Analysis Using Advanced Computational Methods
Orbán, Tomáš ; Dlugoš, Jozef (referee) ; Novotný, Pavel (advisor)
This master’s thesis introduces a slide bearing analysis using the MBS software tool of FEV Virtual Engine, including real surface topography based on 3D roughness measurements. The first half of the thesis gives a brief overview about gasoline combustion engines, slide bearing usage in engines, slide bearing construction and about essential approaches for the characterization of elasto-hydrodynamic behavior. In the second half, the process of model building, rough surface measurement and preparation of analyses are described. At the end of this thesis, the results of the analyses are shown and discussed.
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The Possibilities of Displacement Increase of 4C Zetor Engine
Zloch, Jan ; Franz, Rudolf (referee) ; Dundálek, Radim (advisor)
Diploma thesis aims on mechanical design of new concept of Zetor UŘ III engine with displacement increase and solves calculations of main and pin hydrodynamic bearings of crankshaft. Creo 2 CAD software is used for preparing mechanical design of this new concept. For computation and analysis of hydrodynamic bearings multibody model of crankshaft mechanism is used with flexible FEM model of crankshaft for solving dynamics of mechanism and performing hydrodynamic analysis of bearings in FEV Virtual Engine. Results of this diploma thesis demonstrate the feasibility of new concept of engine and serve as a basis for next engineering tasks before realization of concept.
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An overview of method for studying and quantification of wear
Řeháková, Bára ; Urban, Filip (referee) ; Galas, Radovan (advisor)
This bachelor thesis describes ASTM test methods for determination of wear in accordance to their usefulness to ÚK in FSI VUT in Brno. The beginning concerns with types of wear and their mechanisms and with creation of new test methods. The main section deals with each of the test methods normally used by ÚK and their exact procedures. In the last part of this thesis, comparisons of these are made due to their use according to the type of material.
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Analysis of contaminants in wheel and rail contact
Straka, Tomáš ; Galas, Radovan (referee) ; Kvarda, Daniel (advisor)
Wheel/rail contact is significantly influenced by so called third body – contaminants. Aim of this bachelor’s thesis is to analyse those contaminants in the contact and to create a brief overview. Short introduction into problem of wheel/rail contact is included, followed by description of main contaminants occurring in the contact. This thesis may be used as introduction into contamination of wheel/rail contact problem.
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