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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pryžový tlumič torzních kmitů čtyřválcového vznětového motoru / Rubber damper of a four-cylinder diesel engine

Bauza, Erik January 2010 (has links)
A content of this diploma thesis is construction design of torsional vibration rubber damper of four-stroke diesel supercharged engine. It` s realized evaluation of crankshaft from aspect of torsional vibrations and checked mechanical stress of crankshaft without using rubber damper. Consequently basic parameters of rubber damper are specified, then checked mechanical stress of crankshaft and designed own construction design of damper.
2

Modeling and Control of a Parallel HEV Powertrain with Focus on the Clutch

Morsali, Mahdi January 2015 (has links)
Nowadays, the increasing amount of greenhouse gases and diminishing of the existing petroleum minerals for future generations, has led the automotive companies to think of producing vehicles with less emissions and fuel consumption. For this purpose, Hybrid Electric Vehicles (HEVs) have emerged in the recent decades. HEVs with different configurations have been introduced by engineers.The simulation platform aim for a parallel HEV, where the intention is to reduce the emissions and fuel consumption. The simulation platform includes an Electric Motor (EM) in addition to an Internal Combustion Engine (ICE). A new transmission system is modeled which is compatible with parallel configuration for the HEV, where the inertial effects of the gearbox, clutch and driveline is formulated. The transmission system includes a gearbox which is equipped with synchronizers for smooth change of gears. The HEV is controlled by a rule based controller together with an optimization algorithm as power management strategy in order to have optimal fuel consumption. Using the rule based controller, the HEV is planned to be launched by EM in order to have a downsized clutch and ICE. The clutch modeling is the main focus of this study, where the slipping mechanism is considered in the simulation. In the driveline model, the flexibility effects of the propeller shaft and drive shaft is simulated, so that the model can capture the torsional vibrations of the driveline. The objective of modeling such a system is to reduce emissions and fuel consumption with the same performance of the conventional vehicle. To achieve this goal first a conventional vehicle is modeled and subsequently, a hybrid vehicle is modeled and finally the characteristics of the two simulated models are studied and compared with each other. Using the simulation platform, the state of charge (SOC) of the battery, oscillations of propeller shaft and drive shaft, clutch actuations and couplings, energy dissipated by the clutch, torques provided by EM and ICE, fuel consumptions, emissions and calculation time are calculated and investigated. The hybridization results in a reduction in fuel consumption and emissions, moreover, the energy dissipated by the clutch and clutch couplings are decreased.
3

Nonlinear control schemes for extremum power seeking and torsional vibration mitigation in variable speed wind turbine systems

Fateh, Fariba January 1900 (has links)
Doctor of Philosophy / Department of Electrical and Computer Engineering / Don Gruenbacher / Warren White / This dissertation presents nonlinear control schemes to improve the productivity and lifespan of doubly fed induction generator (DFIG)-based and permanent magnet generator (PMG)-based variable speed wind turbines. To improve the productivity, a nonlinear adaptive control scheme is developed to maximize power capture. This controller consists of three feedback loops. The first loop controls electrical torque of the generator in order to cancel the nonlinear term of the turbine equation of motion using the feedback linearization concept. The nonlinearity cancelation requires a real-time estimation of aerodynamic torque. This is achieved through a second loop which estimates the ratio of the wind turbine power capture versus the available wind power. A third loop utilizes this estimate to identify the shaft speed at which the wind turbine operates at a greater power output. Contrary to existing techniques in literature, this innovative technique does not require any prior knowledge of the optimum tip speed ratio. The presented technique does not need a dither or perturbation signal to track the optimum shaft speed at the maximum power capture. These features make this technique superior to existing methods. Furthermore, the lifespan of variable speed wind turbines is improved by reducing stress on the wind turbine drivetrain. This is achieved via developing a novel vibration mitigation technique using sliding-mode control theory. The technique measures only generator speed as the input signal and then passes it through a high-pass filter in order to extract the speed variations. The filtered signal and its integral are then passed through identical band-pass filters centered at the dominant natural frequency of the drivetrain. These two signals formulate a sliding surface and consequently a control law to damp the drivetrain torsional stress oscillations caused by electrical and mechanical disturbances. This technique provides a robust mitigation approach compared with existing techniques. These control schemes are verified through holistic models of DFIG- and PMG-based wind turbines. Except for wind turbine aerodynamics, for which an existing simulator is used, the developed models of all components including DFIG, PMG, converters, multi-mass drivetrain, and power line are presented in this dissertation.
4

Šestiválcový řadový vznětový motor s vypínáním válců / Six-cylinder in-line diesel engine with cylinder deactivation

Novosád, Ivan January 2020 (has links)
Master 's thesis deals with design of a drivetrain of six cylinder inline engine with cylinder deactivation for heavy agricultural vehicles. In this thesis were devised various possibilities of crankshaft balancing, the best design solution of counterweight was based on optimization in software Catia. Further, the crankshaft was analysed for force and momentum loading and torsional vibration, based on which, the torsional vibration damper was designed. There were considered several options for cylinder deactivation, which were analysed for finest run of engine and the best thermal distribution. Based on these criteria, the best option was to deactivate 2nd and 5th cylinder. The crankshaft was analysed for the fatigue failure by finite element method. The fatigue failure is the most dangerous case for the crankshaft, the resulting safety factor for this limit state is 3,05.
5

Návrh pryžového tlumiče vznětového řadového čtyřválce. / Rubber Damper Design for 4-cylinder In-line CI-engine

Sedlák, Aleš January 2008 (has links)
Design of a rubber damper for 4-cylinder in-line CI-engine is this aim of this thesis diploma. Thesis consists from several parts. First part describes technical solutions of dampers of torsional vibrations. Second part contains torsional vibrations analysis of crankshaft without damper. The last part of this thesis describes design of rubber damper and torsional vibrations analysis of crankshaft with damper.
6

Hnací ústrojí závodního Wankelova rotačního motoru / Powertrain of racing Wankel rotary combustion engine.

Blažo, Marek January 2010 (has links)
The main aim of master’s thesis was to handle the computing proposal and the construction design of the powertrain of racing Wankel rotary engine with 300 kW power output and in the case of 9000 speed per minute. On the basic of these values was made the primary design of the rotary engine, design of the eccentric shaft and rotor housing. Mechanical stress and torsional vibrations of the eccentric shaft were analyzed by using the course of indicator diagram.
7

Realizace edukační úlohy na experimentální stanici pro modelování torzních kmitů / Realization of educational problem based on torsional vibration apparatus

Bartošek, Daniel January 2011 (has links)
The presented master´s thesis deals with realization educational tasks on torsional vibration apparatus. It was designed and tested six educational experiments, to extend student´s knowledge of the static and dynamic properties of rotary systems. On the experimental apparatus it is possible to use inertial discs, adjustable semi-rotary damper with forced vibration crank drive unit. New set of shafts extends the variability of experimental apparatus. Students can realize the measurement of dynamic characteristics and torsional vibration using oscilloscope. New frame for the apparatus which meet all operation requirements was also designed. The solved problematics and all educational tasks are described in new prepared materials for teaching.
8

Pětiválcový vznětový motor pro užitková vozidla / Five-cylinder diesel engine for commercial vehicles

Švarc, Marek January 2017 (has links)
The aim of this diploma thesis is the design of the configuration and the method of balancing the crank mechanism with the specified parameters. For a particular configuration, a crankshaft drawing is processed and a strength analysis, considering the crankshaft torsional vibrations is performed in Ansys FEM software. At the end of the thesis, an ideological design of the torsional vibration damper and its effect on the crankshaft stress in the Ansys FEM software is performed.
9

Čtyřválcový vznětový motor pro užitková vozidla / Four cylinder diesel engine for commercial vehicles

Nikolaychuk, Yaroslav January 2018 (has links)
The diploma thesis focuses on the design of the crankshaft for a four-cylinder diesel engine for commercial vehicles, the main task of this work are the design configuration of the crankshaft balance inertia forces and torques at the crank mechanism, drawing documentation crankshaft design strength check considering torsional vibration.
10

Dvouválcový zážehový motor s excentrickým klikovým mechanismem pro osobní vozidla / Two-cylinder petrol engine with eccentric crank mechanism for passenger vehicles

Freisleben, Pavel January 2015 (has links)
This thesis deals with forces of the crank mechanism. The aim of this work is to find the right value of the eccentricity of the crank mechanism, which will have a positive effect on the size and course of forces that cause friction losses in the crank mechanism. Next solves this balancing eccentric unit. The last part deals with the design and strength check of the crankshaft considering torsional vibration.

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