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Vyvažování hřídelí
Patloka, Jiří
The diploma thesis provides an overview of ways of balancing shafts and rotors of rotating machines. Methods of static and dynamic balancing, types of balancing devices are described and ways of compensating for unbalanced masses. The crankshaft balancing, which is based on the design of a two-cylinder two-stroke engine, is described in more detail. The next part of the work is focused on two-stroke engines and crank mechanism. Here is the principle of operation of two-stroke engines, their use and comparison with four-stroke engines. This part of the work is supplemented by the courses of kinematic quantities from the design of the crank mechanism of a two-stroke engine, the courses of pressure in the cylinders and the courses of forces and moments from the gas pressure. The practical part of the work is the real balancing of the crankshaft on the balancing device Schenck. The method of balancing and the method of balancing unbalanced masses were created. In the end, the results of balancing, their graphical evaluation are summarized and a discussion of the suitability of the chosen balancing procedure and the achieved results is made.
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Hodnocení závad vybrané funkční skupiny spalovacích motorů
Baka, Petr
The bachelor work deals with the rating of clink mechanism in combustion engine. The work is divided into three main parts. The first part pays attention to the recent situation of engine construction in today's passenger cars. The second one describes the construction and material composition of each parts of crank mechanism. The last part concentrates not only on the evaluation of the defects which arise on the crank mechanism, but also describes their dividing according to the cause of each defect
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Mitigating vibration of internal combustion engines
Kožuch, Jonáš ; Böhm, Michael (referee) ; Fridrichová, Kateřina (advisor)
This bachelor thesis deals with the problem of vibration damping of internal combustion engines. It gives an overview of the causes of vibration and describes them. The most dangerous phenomenon for the crankshaft is torsional vibration, and it is therefore important to eliminate this phenomenon as much as possible. An overview of current torsional vibration damping solutions is given. Torsional vibration dampers are divided into different groups. The division is mainly based on the type of construction and the way in which the dampers eliminate the vibrations. The final part focuses on the simulation of the crank dynamics in GT-Suite. In the simulations, the parameters of the rubber torsional damper are varied, specifically the moment of inertia and the Maxwell model settings. Then, their effect on torsional vibration is investigated. The output is the ideal damper parameters for a given engine model.
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High-speed shaft production design
Polesný, Pavel ; Jaroš, Aleš (referee) ; Kalivoda, Milan (advisor)
In the bachelor's thesis, a production process of the crankshaft of a single-cylinder two-stroke engine is designed. The flywheel has a diameter of 20.5 mm, the crank pin has a diameter 9 g6, the connecting rod pin has a diameter 4 g6, and the total length is 63.5 mm. Due to the production batch of 1000 pieces, the machining method was selected. The crankshaft will be produced as a monolith. Then the grooves at the ends of the ground surfaces 9 g6 and 4 g6 were addressed. Due to the wall thickness of 1.25 mm, the surfaces will be without grooves, and a radius or chamfer will be in the corners. The axial bearing and the connecting rod have an internal chamfer of 0.7x45°, thus grooves are unnecessary. The chosen material is 15.142 steel, tempered to a lower strength, supplied in 25x3000 mm bars by ZJP, s.r.o. The semifinished part will be manufactured on a Swiss-type lathe Manurhin K'MX EVO 732. After nitriding, the part will be ground on a Bernardo URS 500 N grinder. For the machining on the EVO 732, OPTIMA EXTREMECUT 46 mineral oil was chosen, and for grinding, a 2% concentration emulsion mixed from BITOL M petroleum emulsion oil was selected. Then the technological process was developed, and operational instructions were created. Calculations determined that 26 bars are needed for the production of the specified series. The entire series production will take just under 4 shifts.
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Piston for Racing Engine Škoda 110
Gerák, Jakub ; Maršálek, Ondřej (referee) ; Svída, David (advisor)
This Bachelor's thesis deals with the defect of the piston Metalex for a racing engine Škoda 110. The aim of my work is to find the reasons for the piston defect, to check the most stressed parts by strength calculation and suggest a possible structural design so that the piston withstands all stresses throughout the required lifespan.
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Three-cylinder Engines
Kočvara, Antonín ; Janoušek, Michal (referee) ; Drápal, Lubomír (advisor)
The main purpose of this thesis is to summarize the progress of four-stroke straight-three engines from the beginning of their production to these days in perspective of parameters and construction. Another goal is to show reasons for their exploitation. The reasons of exploitation are mostly compared to four-cylinder engine and some of them are supported by a calculation. There is also a chapter showing force acting in power train and its influences on straight-three engines. The closing part is dealing with possible ways in future development of straight-three engines.
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Concept of an In-line Spark-ignition Engine
Kočvara, Antonín ; Píštěk, Václav (referee) ; Drápal, Lubomír (advisor)
This thesis deals with comparison of straight four-cylinder petrol engine with a displacement of 1,5 litres and its three-cylinder alternative, which is based on a four-cylinder. The thesis starts with a research, where are examples of some currently manufactured engines. The research is followed by design of both engines, where the design of the crank mechanisms is made more in detail. After that, both crank mechanisms are subjected to dynamic analysis using FEM and MBS methods. The thesis ends with comparison of both engines in terms of crankshaft load, mass and dimensions.
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