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Gaseous fuels for SI engines
Přibyl, Zdeněk ; Czakó, Alexander (referee) ; Štětina, Josef (advisor)
In this bachelor thesis is processed a survey of alternative gaseous fuels for spark-ignition combustion engines. The properties and production, the most important components, infrastructure of service station of specific fuel are stated for these fuels. There are defined the advantages and disadvantages of each fuel. The comparison of CNG and diesel is made. The use of alternative gaseous in the future is outlined at the end of this bachelor thesis.
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Design of a test rig for the development of gears for passenger car applications
Běloušek, Ondřej ; Řehák, Kamil (referee) ; Czakó, Alexander (advisor)
This thesis is aimed to design of test rig which serves for measuring of vibro-acoustic characteristics of gears used in automotive gearboxes. In the theoretical part, the basic principles of initiated vibrations caused by gear meshing are described, especially due to transmission error as an important parameter. Next part of the paper is dedicated to description of experimental approach used in measuring of this characteristic and evaluation of used conceptual designs is also included. Own designed closed loop test rig allows to measure static transmission error of various sizes of gears even if the shafts are not parallel under the specific operating range. The main part of the design is measuring bench, whose developmental phases are shown, and which carries all important components for the measurement. Thesis also includes modal analysis of those constructions performed in ANSYS Workbench. The main parts of closed loop are described in details and static structural analysis of torsional loading device is done. Final part of the thesis compares analytical versus numerical approach to calculate safety factor of the critical point of a chosen shaft.
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Computational Models of Transmission Dynamics
Czakó, Alexander ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This bachelor thesis deals with a summary of knowledge about the computational models of transmission dynamics. Dynamics modelling has different levels of complexity. From the modal, harmonic analysis solved in the FEM, up to creating a virtual prototype in the MBS softwares. In the introduction, there are presented the basics of analytical dynamics and mechanical oscillation which are the basis of individual analysis. Vibration sources in transmission are described as well.
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Mechanical losses of modern powertrains
Vaňkátová, Kateřina ; Czakó, Alexander (referee) ; Štětina, Josef (advisor)
This bachelor thesis deals with the issue of mechanical losses in internal combustion engines of passenger cars. The following chapters describe the origin of mechanical losses, the area of their occurrence in the engine and in the accessories driven by the engine. Furthermore, the work summarizes the current knowledge in the field of reducing mechanical losses and methods of determining the engine losses during their development. The aim of this work is to acquaint the reader not only with the issue of mechanical losses, but also with their significant negative impact.
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Determination of transmission error at helical gear
Czakó, Alexander ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This diploma thesis primarily deals with the transmission error issue which is one of the dominant sources of vibration in gear pairs and transmission systems. The vibrations subsequently generate noise which is often subjected to increasingly stricter demands across the industry, including the automotive one. It turns out that reducing the peak-to-peak value of the transmission error has a beneficial effect on the vibro-acoustic properties of gears and gear pairs. This thesis aims to determine the transmission error under static conditions, since a gear pair with a low static transmission error is a good assumption for a low transmission error even under dynamic effects. The resulting values of the transmission error can be influenced already during the design of the gear macro-geometry. It is also suitable to apply micro-geometric adjustments – modifications to the gear teeth. For this reason, the search part of the thesis is dedicated to theoretical knowledge, especially concerning the geometry of gears, modifications of teeth and the overall transmission error and its determination. The transmission error can be determined in several ways, including a technical experiment. However, due to time and financial reasons, this is not always possible, and therefore, the possibility of using numerical simulations is offered. In this thesis, the approach using stress-strain quasi-static contact analysis using the finite element method in Ansys Workbench software is used. The advantage is, among other things, a good comparability of results. The input to the FEM analysis is 3D CAD geometry – in this case, it is specifically a helical gear pair with parallel axes. The model/assembly of this gear pair is created in PTC Creo software fully parametrically, so it is possible to generate arbitrary gear pair configurations by changing the input parameters, which significantly saves time. At the end of this diploma thesis, the stress-strain analysis of various gear configurations is evaluated, with respect to the equivalent stress and contact pressure. Furthermore, the static transmission error – its graphs and peak-to-peak values – is determined from FEM analyses for different gear geometry, including tooth modifications, and for various loading torques. Last but not least, the effects of contact/overlap ratio and centre distance are evaluated.
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Design of a winch for a manual crane
Kolínek, Jakub ; Czakó, Alexander (referee) ; Rekem, Jakub (advisor)
This bachelor thesis deals with the construction of the winding mechanism of the historical hand-operated crane JŽ 600, not only covering the construction itself, but also giving a general overview of the hand-operated cranes used today. The work further addresses the description of the individual components of the hand-operated crane, their function and the requirements placed on them. Many concepts contributed to the emergence of the final design, which was gradually modified to be functional, meet all safety requirements based on the standards and not be unnecessarily complicated. For the strength verification of components with complex shape the finite element method was used. The result of this work is a functional design of the winding mechanism used for the reconstruction of the incomplete crane JŽ600.
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Design of a test rig for the development of gears for passenger car applications
Běloušek, Ondřej ; Řehák, Kamil (referee) ; Czakó, Alexander (advisor)
This thesis is aimed to design of test rig which serves for measuring of vibro-acoustic characteristics of gears used in automotive gearboxes. In the theoretical part, the basic principles of initiated vibrations caused by gear meshing are described, especially due to transmission error as an important parameter. Next part of the paper is dedicated to description of experimental approach used in measuring of this characteristic and evaluation of used conceptual designs is also included. Own designed closed loop test rig allows to measure static transmission error of various sizes of gears even if the shafts are not parallel under the specific operating range. The main part of the design is measuring bench, whose developmental phases are shown, and which carries all important components for the measurement. Thesis also includes modal analysis of those constructions performed in ANSYS Workbench. The main parts of closed loop are described in details and static structural analysis of torsional loading device is done. Final part of the thesis compares analytical versus numerical approach to calculate safety factor of the critical point of a chosen shaft.
|
|
|
Mechanical losses of modern powertrains
Vaňkátová, Kateřina ; Czakó, Alexander (referee) ; Štětina, Josef (advisor)
This bachelor thesis deals with the issue of mechanical losses in internal combustion engines of passenger cars. The following chapters describe the origin of mechanical losses, the area of their occurrence in the engine and in the accessories driven by the engine. Furthermore, the work summarizes the current knowledge in the field of reducing mechanical losses and methods of determining the engine losses during their development. The aim of this work is to acquaint the reader not only with the issue of mechanical losses, but also with their significant negative impact.
|
|
|
Gaseous fuels for SI engines
Přibyl, Zdeněk ; Czakó, Alexander (referee) ; Štětina, Josef (advisor)
In this bachelor thesis is processed a survey of alternative gaseous fuels for spark-ignition combustion engines. The properties and production, the most important components, infrastructure of service station of specific fuel are stated for these fuels. There are defined the advantages and disadvantages of each fuel. The comparison of CNG and diesel is made. The use of alternative gaseous in the future is outlined at the end of this bachelor thesis.
|
|
|
Determination of transmission error at helical gear
Czakó, Alexander ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This diploma thesis primarily deals with the transmission error issue which is one of the dominant sources of vibration in gear pairs and transmission systems. The vibrations subsequently generate noise which is often subjected to increasingly stricter demands across the industry, including the automotive one. It turns out that reducing the peak-to-peak value of the transmission error has a beneficial effect on the vibro-acoustic properties of gears and gear pairs. This thesis aims to determine the transmission error under static conditions, since a gear pair with a low static transmission error is a good assumption for a low transmission error even under dynamic effects. The resulting values of the transmission error can be influenced already during the design of the gear macro-geometry. It is also suitable to apply micro-geometric adjustments – modifications to the gear teeth. For this reason, the search part of the thesis is dedicated to theoretical knowledge, especially concerning the geometry of gears, modifications of teeth and the overall transmission error and its determination. The transmission error can be determined in several ways, including a technical experiment. However, due to time and financial reasons, this is not always possible, and therefore, the possibility of using numerical simulations is offered. In this thesis, the approach using stress-strain quasi-static contact analysis using the finite element method in Ansys Workbench software is used. The advantage is, among other things, a good comparability of results. The input to the FEM analysis is 3D CAD geometry – in this case, it is specifically a helical gear pair with parallel axes. The model/assembly of this gear pair is created in PTC Creo software fully parametrically, so it is possible to generate arbitrary gear pair configurations by changing the input parameters, which significantly saves time. At the end of this diploma thesis, the stress-strain analysis of various gear configurations is evaluated, with respect to the equivalent stress and contact pressure. Furthermore, the static transmission error – its graphs and peak-to-peak values – is determined from FEM analyses for different gear geometry, including tooth modifications, and for various loading torques. Last but not least, the effects of contact/overlap ratio and centre distance are evaluated.
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