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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.
31

Návrh a optimalizace sacího a výfukového potrubí zážehového motoru / Intanke and exhaust manifold for racing engine

Chuchma, Ondřej January 2010 (has links)
This Master’s thesis is focused on design and optimalization of intake and exhaust system of the C20XE engine. It is four-cylinder gasoline engine with stroke volume of two litres, which was produced by car company Opel. This engine is determined for Opel Astra F automobile, that is build for racing. For optimalization of dimension parameters there is used a Lotus Engine simulation software, which simulates one-dimension gas flowing in manifold. 3D CAD models are made in Pro ENGINNER software.
32

Zvýšení pružnosti zážehového jednoválcového motoru formule Student / Single Cylinder SI Engine for Formula Student

Adámek, Ladislav January 2011 (has links)
Diplomová práce je zaměřena na konstrukční návrh sacího potrubí pro vůz Formula Student. Pro pohon vozu je použit jednoválcový atmosférický benzinový motor Husaberg FE 570. Sací potrubí je navrhováno tak, aby bylo v souladu s pravidly Formula Student. Pro zvýšení plnící účinnosti sací potrubí využívá resonančního efektu. Délky sacího potrubí byly spočítány v software Lotus Engine simulation.
33

Návrh řídicího algoritmu pro elektromechanický aktuátor s výrazným suchým třením / Design of controller for electromechanical actuator with significant dry friction

Veselý, Antonín January 2015 (has links)
This work deals with identification of systems with high dry friction and/or return spring. Identified models are optimised by Parameter Estimation toolbox. Because friction and return spring have negative influence in control systems, models are used as compensators in control loop. Also effect of parameters variation is investigated in this paper.
34

Implementation of a Model Predictive Controller in a Spark-Ignition Engine

Mann, Gustav, Luedtke, Jakob January 2021 (has links)
The propulsion of the spark-ignition engine has been investigated and developed during the past century to improve driveability, minimize fuel consumption and emissions, resulting in highly engineered and computerized powertrains. Well balanced engine maps containing coordinated set-points and model-based information sharing have solved the cross-coupling between different control loops. During transitions between the operating conditions a disadvantageous transient behavior that affects the engine performance may occur. By implementing an MPC as a superior controller a nearly optimal control solution was accomplished. A digital twin of the SI engine was designed through collected measurements and system modeling. The twin made it possible to investigate and elaborate different cost functions in a simulation environment before applying the controller in real-time. By utilizing MPC together with the engine maps a strong relationship between the throttle and iVVT actuator was achieved, which removed the cross-coupling between the actuator control loops and reduced the unfavorable transient behavior.
35

Gestion des connaissances pour la conception collaborative et l’optimisation multi-physique de systèmes mécatroniques / Knowledge management for collaborative design and multi-physical optimization of mechatronic systems

Mcharek, Mehdi 12 December 2018 (has links)
Les produits mécatroniques sont complexes et multidisciplinaires par nature. Les exigences pour les concevoir sont souvent contradictoires et doivent être validées par les différentes équipes d'ingénierie disciplinaire (ID). Pour répondre à cette complexité et réduire le temps de conception, les ingénieurs disciplinaires ont besoin de collaborer dynamiquement, de résoudre les conflits interdisciplinaires et de réutiliser les connaissances de projets antérieurs. De plus, ils ont besoin de collaborer en permanence avec l’équipe d’ingénierie systèmes (IS) pour avoir un accès direct aux exigences et l’équipe d’optimisation multidisciplinaire (OMD) pour valider le système dans sa globalité.Nous proposons d'utiliser des techniques de gestion des connaissances pour structurer les connaissances générées lors des activités de collaboration afin d'harmoniser le cycle de conception. Notre principale contribution est une approche d'unification qui explique comment IS, ID et OMD se complètent et peuvent être utilisés en synergie pour un cycle de conception intégré et continu. Notre méthodologie permet de centraliser les connaissances nécessaires à la collaboration et au suivi des exigences. Elle assure également la traçabilité des échanges entre les ingénieurs grâce à la théorie des graphes. Cette connaissance formalisée du processus de collaboration permet de définir automatiquement un problème OMD. / Mechatronic products are complex and multidisciplinary in nature. The requirements to design them are often contradictory and must be validated by the various disciplinary engineering (DE) teams. To address this complexity and reduce design time, disciplinary engineers need to collaborate dynamically, resolve interdisciplinary conflicts, and reuse knowledge from previous projects. In addition, they need to work seamlessly with the Systems Engineering (SE) team to have direct access to requirements and the Multidisciplinary Design Optimization (MDO) team for global validation. We propose to use Knowledge Management techniques to structure the knowledge generated during collaboration activities and harmonize the overall design cycle. Our primary contribution is a unification approach, elaborating how SE, DE, and MDO complement each-other and can be used in synergy for an integrated and continuous design cycle. Our methodology centralizes the product knowledge necessary for collaboration. It ensures traceability of the exchange between disciplinary engineers using graph theory. This formalized process knowledge facilitates MDO problem definition.
36

Pedálová skupina Formule Student / Formula Student Pedal Assembly

Skula, Libor January 2013 (has links)
This thesis is concerned with design of pedal box for Formula Student vehicle. Summary of design solutions is presented in introductory chapter, especially those used in Formula Student competition. Designed assembly is divided into parts of single pedals and base plate. The proposed design is supported by stress analysis of loaded parts in pedal box. In conclusion, design is reviewed in terms of the results, as well as compared with current pedal box.
37

<b>Design and Control of a Multi-Pressure Rail System for Agricultural Vehicles</b>

Xiaofan Guo (18404121) 18 April 2024 (has links)
<p dir="ltr">Hydraulic actuation technology is one of the most common ways of transferring power in agricultural and construction machinery. As the system efficiency and fuel consumption of these machines gains more attention due to climate change, a new generation of high-efficient hydraulic architecture is in need. This dissertation presents a study for reducing energy loss in the hydraulic control system of agricultural tractors and their implements. The solution is referred to as a multi-pressure rail (MPR) system and provides power to the hydraulic functions following a pressure control logic, as opposed to the traditional flow control logic typical of hydraulic systems used in off-road vehicles.</p><p dir="ltr">The proposed hydraulic architecture and controller allows for elimination of redundant flow control valves in the state-of-the-art system, which cause excessive throttling losses leading to poor overall energy efficiency. Related work on MPR technology targets construction vehicles, where the MPR solution can allow energy recovery during overrunning loads and better engine management. This study alternatively addresses the case of agricultural applications where functions mostly operate under resistive load conditions with slow dynamics, which offers an opportunity to target throttle losses. The hydraulic architecture design starts with the choice of number of rails, then supply system and pressure selection and control valve set. Next, the controller is proposed. The controller contains two layers. The lower layer directly controls the command tracking, rotational speed, or pressure, for each subsystem. The higher layer, namely the supervisory controller, optimizes the rail pressure levels in real time to guarantee minimum overall throttling loss.</p><p dir="ltr">To prove the effectiveness of the hydraulic system architecture and controller design, a standalone test rig was conceived and used to validate a numerical simulation model of the MPR system and its control strategy. Particular focus is given to the dynamic behavior of the system during the switches of a function between different pressure rails, which needs to ensure reduced oscillations of the flow provided to each hydraulic function. Then, to demonstrate the ability on power saving in real working conditions, reference machines were chosen: a 435 hp hydraulic tractor powering a 16-row planter, for which operating features during typical drive cycles were available to the authors. Simulation models of the two reference machines were built and validated with in field experiments. A full MPR system model on the reference machines was constructed using the validated models. This full model was used to predict the reference tractor and planter hydraulic system performance and power consumption during typical drive cycles. The results show up to 52.4% total power reduction at the pump shaft, corresponding to 113.8% system efficiency gain.</p><p dir="ltr">The dissertation also laid out the planned activities to complete the study. The system controller will be generalized that could suit more equipment in addition to the reference machine in this study. In the meantime, the reference tractor and planter will be modified into the proposed MPR system for field testing. That includes new sensors, controllers, valves, etc. The field test is the final experimental validation for the proposed MPR system on the front of effectiveness and power saving in real working condition.</p>
38

Evaluation of the ZDES method on an axial compressor : analysis of the effects of upstream wake and throttle on the tip-leakage flow. / Evaluation de la méthode ZDES sur un compresseur axial : analyse des effets de sillages venant de l’amont et du vannage sur le tourbillon de jeu

Riera, William 27 November 2014 (has links)
L’écoulement de jeu dans les compresseurs axiaux est étudié à l’aide de la Zonal Detached Eddy Simulation (ZDES). L’objectif consiste à évaluer la capacité de méthodes hybrides URANS/LES à simuler l’écoulement de jeu d’un compresseur axial réaliste afin de mieux comprendre la physique de cet écoulement, notamment son comportement au vannage ainsi que l’effet de sillages venant du stator amont sur le rotor aval. Après avoir choisi la méthode hybride ZDES, un banc d’essai numérique est défini afin de simuler le premier rotor du compresseur de recherche CREATE. Ce banc a la particularité de pouvoir prendre en compte les effets instationnaires venant de la roue directrice d’entrée (RDE), notamment son sillage ainsi que les tourbillons générés en pied et en tête. Basé sur des critères de maillage ZDES, il est utilisé pour évaluer cette méthode comparativement aux méthodes classiques RANS et URANS. La ZDES est validée par étape jusqu’à une analyse spectrale de l’écoulement de jeu se basant sur des données expérimentales. Elle s’est révélée capable de capturer plus précisément l’intensité et la position des phénomènes instationnaires rencontrés en tête du rotor, notamment le tourbillon de jeu. Les densités spectrales de puissance analysées montrent que cela est dû en partie à une meilleure prise en compte du transfert d’énergie des grandes vers les petites structures de l’écoulement avant leur dissipation. De plus, l’écart entre les approches s’accentue lorsque le tourbillon de jeu traverse le choc en tête. Proche pompage, les effets d’interaction entre le choc, le tourbillon de jeu, la couche limite carter et le tourbillon venant de la tête de la RDE sont amplifiés. Le décollement de la couche limite carter s’accentue et une inversion locale de l’écoulement est observée. De plus, le tourbillon de jeu s’élargit et est dévié vers la pale adjacente, ce qui intensifie le phénomène de double écoulement de jeu. L’interaction du tourbillon venant de la tête de la RDE avec le choc et le tourbillon de jeu du rotor est ensuite étudiée au point de dessin. Un battement du tourbillon de jeu est rencontré lors de l’interaction de ce tourbillon avec le tourbillon de tête de la RDE, ce qui diminue le double écoulement de jeu. / The tip-leakage flow in axial compressors is studied with the Zonal Detached Eddy Simulation (ZDES). This study aims at evaluating the capability of hybrid URANS/LES methods to simulate the tip-leakage flow within a realistic axial compressor in order to better understand the involved physics, especially the behaviour of the flow near surge and the effects of stator wakes on the downstream rotor. Once the ZDES method is chosen, a numerical test bench is defined to simulate the first rotor of the research compressor CREATE. This bench takes into account the unsteady effects of the Inlet Guide Vane (IGV), such as its wake as well as vortices generated at the IGV hub and tip. It is based upon ZDES meshing criteria and is used to evaluate this method compared to classic RANS and URANS approaches. A method validation is carried out up to a spectral analysis compared to experimental data. The ZDES is capable to capture more accurately the intensity and position of the unsteady phenomena encountered in the tip region, especially the tip-leakage vortex. The power spectral densities highlight that this partly originates from a better capture of the energy transfer from large to small structures until their dissipation. The discrepancy between the methods is accentuated as the tip-leakage vortex crosses the shock. Near the surge line, the interactions between the shock, the tip-leakage vortex, the boundary layer developing on the shroud and the vortex generated by the IGV tip are amplified. The boundary layer on the shroud separates earlier and a local flow inversion occurs. Besides, the tip-leakage vortex widens and is deflected toward the adjacent blade. This strengthens the double leakage. At the design operating point, the interaction of the IGV tip vortex with the shock and the rotor tip vortex is studied. A vortex flutter is observed as the IGV tip vortex arrives on the rotor blade and stretches the rotor tip vortex. This phenomenon decreases the double leakage.
39

Elektronická škrticí klapka / Electronic throttle

Dušek, Jiří January 2011 (has links)
The aim of this master’s thesis was to analyze the contemporary electronic throttles and the requirements imposed on them. Then to build the mathematical model, identify parameters of the given electronic throttle, proceed the verification and on its basis to build the simulation model. There were selected suitable control and high power components to control the electronic throttle. Due to the knowledge of these parameters the simulation model was extended. For this extended simulation model was designed the position cascade controller with speed and current control loop. Using the designed controller the implementation of the electronic throttle control and the available high power and control module was realized.
40

Aplikace lokálních aproximátorů pro řízení reálného mechatronického systému / Application of local approximators for control of real mechatronic system

Palaj, Lukas January 2011 (has links)
Cieľom práce je aplikácia lokálnych aproximátorov pre riadenie reálnych mechatronických sústav pomocou metódy dopredného riadenia predstavujúcej zaujímavú alternatívu k metódam využívajúcim globálne aproximátory. Po ukážkových príkladoch funkcie lokálnych aproximátorov bol navrhnutý algoritmus implementovaný pre riadenie dvoch sústav, elektronickej škrtiacej klapky a výukového modelu magnetickej levitácie, predstavujúcich vysoko nelineárne a nestabilné sústavy. Skúmali sme, či riadiaci algoritmus bude mať pozitívny vplyv na presnosť regulácie, ďalej bola skúmaná jeho schopnosť prispôsobiť sa zmene parametrov sústavy a tiež prípadná možnosť jeho implementácie pre mikrokontrolér znížením vzorkovacej frekvencie. Výsledky ukázali, že riadenie založené na lokálnych modeloch zlepšilo riadenie v porovnaní s jednoduchým PID regulátorom a že má schopnosť adaptability. Veľmi výhodné sa zdá byť jeho použitie pre zariadenia umožnujúce vzorkovaciu frekvenciu do 1 kHz.

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