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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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Analysis of crank and cam shaft position sensor variability
Riečica, Samuel ; Repka, Martin (referee) ; Šebela, Kamil (advisor)
This bachelor thesis deals with the working characteristics of crankshaft and camshaft position sensors used in the power unit to ensure correct injection and ignition of the fuel mixture. Their variability was determined by experimental comparison of sensor characteristics. Search of the types and designs of sensors used was carried out in the first phase. Measuring device, which represented a simplified shaft model for sensing characteristics, was designed and constructed in the next step. The experiment was conducted on a statistical sample of 100 pieces of sensors using the Hall effect. The characteristics of the sensors were recorded and evaluated using an oscilloscope with appropriate digital software. Statistical processing of the measured data was performed at the end of the thesis. The results show that the variability of the crankshaft and camshaft position sensors can have an impact on engine performance characteristics and exhaust emissions produced.
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Analysis of the crank mechanism of a two-stroke engine
Matyáš, David ; Píštěk, Václav (referee) ; Svída, David (advisor)
This diploma thesis is a comparison of two versions of the crank mechanism of the Jawa 350 two-stroke engine. The diploma thesis if prefaced by researching the design solutions of multi-cylinder two-stroke engines with examples of their use. The following is a description of the theoretical properties of the two examined crank mechanisms in terms of inertial effects. For both engine concepts, the engine performance characteristics is measured and compared to each other. The engine with modified crankshaft is subjected to a pressure indication, which serves as one of the inputs to the strength analysis of the crankshaft. This is done by a combination of MBS simulation, FEM analysis and calculation of fatigue safety factor by LSA analytic method.
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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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Silicone damper of a six-cylinder in-line diesel engine
Drozdek, Lukáš ; Novotný, Pavel (referee) ; Píštěk, Václav (advisor)
This thesis "Silicone damper of a six-cylinder in-line diesel engine " is focused on the proposal of alternative using of silicone damper for the a six-cylinder in-line diesel engine, which is made for tractors and other industrial aplications. The aim of this thesis is to count the oscilation of crankshaft by the help of appropriate dynamic model, then to propose such a basic parameters of silicone damper, which absorbes torsion blip crankshaft to acceptable value. The next part of my thesis is proposal of the constructive implementation of fixation the silicone damper on the free part of crankshaft. The last part of my thesis is comparing and evaluating the oscilation of crankshaft without a dumper and with a new propsal of the silicone damper.
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