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Crank train of a two-stroke racing motorcycle engine
Šmahel, Matěj ; Tobiáš, Martin (referee) ; Drápal, Lubomír (advisor)
This diploma thesis deals with numerical-construction design of a two-stroke single cylinder internal combustion engine crankshaft. First part of diploma thesis describes main force effects of crank train and describes selected two-stroke engine. The second part of this diploma thesis is dedicated to numerical modelling of crank train in Multi-Body System. The main goal is to determine an effect of balance factor to motorcycle components. Loads of main crankshaft bearing and engine mounts are evaluated. Acceleration in handlebars and attachment points for footrest is also determined. The results are summarised, and further possible process is outlined.
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Conversion of a gasoline engine to burn hydrogen
Prchal, David ; Böhm, Michael (referee) ; Drápal, Lubomír (advisor)
The master’s thesis deals with the hydrogen combustion in reciprocating internal combustion engines, a topic that is becoming more important with the planned transition to low-emission mobility. basic physical properties of hydrogen, which are compared with conventional hydrocarbon fuels. Differences in terms of mixture formation, heat release rate, heat transfer, performance, emissions and other operating parameters are described. Based on the information found, a theoretical proposal for the conversion of the 1.5 TSI evo2 gasoline engine to hydrogen combustion is made, with emphasis on achieving sufficient power, a suitable torque curve, low emissions and the lowest possible conversion costs. Data from other hydrogen spark ignition engines are analysed and few different combustion models for hydrogen are developed. A simplified 1D model of the baseline engine is created and modified for hydrogen applications. A new intake cam profile is designed for the high engine load, the approximate size of the required turbocharger is recommended, intake air cooling requirements are determined and minor structural modifications to the cylinder head are proposed. The result meets the stated objectives and demonstrates that modern spark ignition internal combustion engines can be used in combination with hydrogen as a low-emission fuel with low conversion costs.
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Variable compression ratio for spark-ignition four-cylinder engine
Rada, Jan ; Fridrichová, Kateřina (referee) ; Drápal, Lubomír (advisor)
The automotive industry faces pressure to increase engine efficiency and reduce emissions. One promising solution is the implementation of variable compression ratio technology, which allows for the dynamic adjustment of the engine's compression ratio according to operating conditions, thereby improving efficiency, saving fuel, and reducing emissions. This thesis focuses on the analysis and design of a four-cylinder spark-ignition engine with variable compression ratio technology. The work compares the baseline engine with the modified engine in terms of installation space and weight, incorporating theoretical foundations of variable compression ratio and practical aspects of its implementation. The introductory part includes a literature review on variable compression ratio engines, followed by the conceptual design of the engine and an analysis of the crank mechanism. The main part of the thesis is the design, which aims to maximize the use of components from the original engine. The resulting kinematic and force analyses support the potential of this technology for developing more efficient engines.
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Motorcycle wheel force transducer
Krišpín, Jakub ; Drápal, Lubomír (referee) ; Tobiáš, Martin (advisor)
This thesis deals with the design of a driven motorcycle measuring wheel. The wheel is designed for a KTM RC 390 motorcycle but can be used on another motorcycle if the centre section is replaced. The wheel is designed to measure torque and longitudinal and vertical force, which is very useful for analysing the dynamics of the motorcycle. The measurement systems designed to measure the forces and moments on the wheels of the vehicles are introduced in the beginning of this thesis. Furthermore, the wheel design for the selected motorcycle is presented including the optimization of the wheel spoke shape. The optimized shape creates a region of homogeneous stress where strain gauges are installed to measure torque. Subsequently, structural analysis is performed in Ansys software using FEM. It verifies the structure in terms of strength. Then suitable strain gauges are selected and their wiring is designed. The proposed measuring wheel should serve as an alternative to commercially available measuring systems which are very expensive. The material cost of the presented wheel is approximately 78 thousand CZK.
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Two Stroke Engine Indirect Fuel Injection
Kovář, Michal ; Drápal, Lubomír (referee) ; Janoušek, Michal (advisor)
This diploma thesis deals with indirect fuel injection on new two-stroke engine for motocross sidecar. The purpose of this work was to design the fuel injection system together with length of the fuel injection times. To determine the fuel injection times, it was necessary to determine the complete exhaust system that affect the volumetric efficiency. The conclusions were based on research in the field of two-stroke engines and calculations determining the amount of fuel per one cycle. The injection method together with the location of the fuel injector and type of fuel injector that can be use were determined and then the injection times that can be entered in the ECU.
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The influence of a computational model of crank train dynamics on engine block load
Charvát, Adam ; Dlugoš, Jozef (referee) ; Drápal, Lubomír (advisor)
This work investigates the influence of the computational model of the cranktrain dynamics on the engine block load around the main bearings depending on the discretization level of the bodies used. Four variants of the computational model of the cranktrain in the Multi-Body System software SIMDRIVE 3D are compared with respect to the load on the main bearings. Based on the obtained loads, a strength analysis of the EA211 series 1,5 MPI mass-production engine block, manufactured by ŠKODA AUTO, is performed, including the influence of pre-stress during the assembly of the cylinder head and bearing caps. To evaluate the results, a fatigue life calculation is performed, and the endurance safety factors in the grooves on the bottom of the engine block are compared.
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Over-expanded internal-combustion engines
Novotný, Pavel ; Janoušek, Michal (referee) ; Drápal, Lubomír (advisor)
At the beginning there is a short history of over-expanded engines. Subsequently, the thermodynamics of ideal over-expanded cycles are analysed and compared with the ideal Otto cycle. The thesis also deals with some design solutions for achieving over-expansion in an internal combustion engine. In the thesis there are also selected over-expanded engines from leading world carmakers. At the end the thesis deals with systems with variable compression ratio.
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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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Application of plain bearings for four-stroke internal combustion engines
Šedo, Matej ; Janoušek, Michal (referee) ; Drápal, Lubomír (advisor)
Subject of this thesis are plain bearings and especially their application for four-stroke internal combustion engines. Thesis is divided into two main parts. The first part provides a basic description of plain bearings, their distribution and evolution. It also discusses their materials and the theory of hydrodynamic lubrication. The second part covers concept of sliding bearings in internal combustion engines and their load associated with the election of right material. It also includes description of particular application of plain bearings and the method of oil distribution. It handles the mounting of crankshaft and camshaft, piston pin, connecting rod and other places where sleeve bearings are use.
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