Dissertations / Theses on the topic 'Pro/ENGINEER Mechanica'

Im Vortrag werden alle derzeit bestehenden Simulations-Werkzeuge im Überblick vorgestellt und deren Anwendung an einzelnen Beispielen verdeutlicht. Desweiteren beinhaltet der Beitrag die Vorstellung der wesentlichen Neuerungen der Pro/ENGINEER Version Wildfire 5 auf dem Gebiet Simulation. Dabei wird auf die Dynamische Analyse und die Erweiterungen in Mechanica besonders eingegangen.

In dieser Präsentation wird das universelle FE-Modell eines Kegelrollenlagers vorgestellt. Mittels eines Pro/ENGINEER-Layouts, basierend auf dem Top-Down Designkonzept, kann automatisch innerhalb einer kurzen Bearbeitungszeit ein geprüftes und lauffähiges FE-Modell eines Kegelrollenlagers abgeleitet werden. Dieses Modell kann z.B. in großen Getriebemodellen eingebaut werden, um eine quasistatische Betrachtung mit korrekten Lagersteifigkeiten zu ermöglichen.

This thesis deals with construction proposal of front axle consoles for tractor Zetor Forterra. The aim of this work is to design and construct the 3D console model, which will be put through a solidity analysis. Based on this analysis the console will be optimized according to the solidity needs. The model proposal is realized in the software Pro/Engineer. Following strength calculations are realized in the software Pro/Mechanica.

Part 1: Theoretic background information - Review of Hooke’s law for linear elastic materials - The strain energy density of linear elastic materials - Hyperelastic material - Material laws for hyperelastic materials - About selecting the material model and performing tests - Implementation of hyperelastic material laws in Mechanica - Defining hyperelastic material parameters in Mechanica - Test set-ups and specimen shapes of the supported material tests - The uniaxial compression test - Stress and strain definitions in the Mechanica LDA analysis Part 2: Application examples - A test specimen subjected to uniaxial loading - A volumetric compression test - A planar test - Influence of the material law Appendix - PTC Simulation Services Introduction - Dictionary Technical English-German<br>Teil 1: Theoretische Hintergrundinformation - Das Hookesche Gesetz für linear-elastische Werkstoffe - Die Dehnungsenergiedichte für linear-elastische Materialien - Hyperelastisches Material - Materialgesetze für Hyperelastizität - Auswählen des Materialgesetzes und Testdurchführung - Implementierung der hyperelastischen Materialgesetze in Mechanica - Definieren der hyperelastischen Materialparameter in Mechanica - Testaufbauten und Prüfkörper der unterstützten Materialtests - Der einachsige Druckversuch - Spannungs- und Dehnungsdefinition in der Mechanica-Analyse mit großen Verformungen Teil 2: Anwendungsbeispiele - Ein einachsig beanspruchter Prüfkörper - Ein volumetrischer Drucktest - Ein planarer Test - Einfluss des Materialgesetzes Anhang: - Kurzvorstellung der PTC Simulationsdienstleistungen - Wörterbuch technisches Englisch-Deutsch

- Allgemeine Problematik bei der FEM-Simulation von Lagern/Gelenken - Modellierungstechniken in MECHANICA wie z.B. Kontakt-Analysen, Balkenspinnen, gewichtete Verbindungen, orthotropes Material, etc. - Vergleich dieser Techniken und Diskussion der Vor- und Nachteile anhand eines Gleitlagers - Empfehlungen und Regeln

Der Vortrag stellt das neue, unendlich reibungsbehaftete Kontaktmodell der FEM-Berechnungssoftware Pro/ENGINEER Mechanica in der Version Wildfire 4.0 von PTC vor. Dabei werden sowohl die Grundlagen des reibungsfreien Kontaktes als auch die Theorie des unendlich reibungsbehafteten Kontaktmodells behandelt sowie die Grundlagen der zur numerischen Lösung in der Software verwendeten Penalty- und Newton-Raphson-Methode erläutert. Als Anwendungsbeispiel für das reibungsfreie Kontaktmodell wird ein Zylinderrollenlager vollständig mit sämtlichen Wälzkontakten für verschiedene Lager- und Einbauspiele berechnet, die Ergebnisse umfassend dargestellt sowie eine analytische Gegenrechnung nach der Hertzschen Theorie ausgeführt, die sehr gute Übereinstimmung mit der numerischen Simulation zeigt. Für das reibungsbehaftete Kontaktmodell wird exemplarisch eine geschrumpfte Welle-Nabe-Verbindung unter Torsion berechnet. Diese wird einer analytischen Lösung sowie verschiedenen 2D-Idealisierungen (ebener Spannungszustand, ebener Dehnungszustand, 2D-Axialsymmetrie) gegenübergestellt.

<p>This report is the result of a thesis as been implemented during the spring term 2009 at</p><p>the University of Gävle.</p><p>The company Bruks produces mobile chippers which are used for chipping logging</p><p>slash, roundwood and parts of trees. The chipper is powered by a separate diesel engine</p><p>and the chipper can be assembled on trucks, trailers or some other carrier vehicles.</p><p>When the chip has passed the chipper drum, the chip is collected in an integrated bin</p><p>which is mounted on the vehicles frame with dumping yokes. When these dumping</p><p>yokes were designed they were probably created with large material dimensions. The</p><p>aim with the degree project is hence to study the strengths of materials and, if possible,</p><p>to suggest an arrangement that can decrease the total weight on the dumping yoke on</p><p>Bruks´ mobile chippers 805 CT.</p><p>The CAD-program Pro/ENGINEER was used during the project for outlining the 2Ddrawings,</p><p>as distributed of constructors on Bruks, to solid 3D-parts. The three-dimensional</p><p>assembly from Pro/ENGINEER was transferred to Pro/MECHANICA. The construction is</p><p>complex and contains many components, and therefore the model has been divided into two</p><p>different parts, the external and the internal dumping yoke.</p><p>The conclusion of the degree project is that the product generally is not over dimensioned.</p><p>However there are many options for optimizing, mainly on the external dumping yokes.</p>

This diploma thesis deals with the design of a two-stroke engine for paragliding. First of all, the different types and designs of two-stroke engines are discussed. After the design of the crank mechanism, the forces in the engine are tested, followed by the strength control of selected components. In addition, the work includes design of individual engine components, propeller reducer and 3D models of components and motor unit.

<p>Målet med detta examensarbete är att ersätta den tidigare lösningen av sensorfingret med andra komponenter, eller hitta en annan sensor med motsvarande funktion.</p><p>Arbetet har begränsats av att ESAB vill ha ett mekaniskt finger för användarvänlighetens skull. Efter en förundersökning av olika typer av sensorer har vi valt att använda oss av trådtöjningsgivare som sensorer till det mekaniska sensorfingret. I och med detta val behövde vi även komma med ett teoretiskt förslag på en mekanisk upphängning av sensorfingret.</p><p>Vi har byggt upp två separata Wheatstonebryggor med varsin instrumentförstärkare (INA125). Utsignalen från bryggorna är relativt liten och behövde förstärkas cirka 2000 gånger.</p><p>Nollbalansering av bryggorna har skett manuellt med potentiometrar men vi har även gett ett förslag på en lösning där nollbalansering kan ske med ett enkelt knapptryck. Knappen är placerad på upphängningen på ett sådant sätt att man inte kan trycka oavsiktligt på knappen.</p><p>Resultatet av arbetet är en uppkoppling på en experimentplatta samt förslag på hur upphängningen och sensorfingret designmässigt kan se ut.</p><p>För vidare arbetsgång behövs en prototyp för att testa livslängden och ta reda på vilken känslighet som är mest optimal.</p><br><p>The goal with this degree project was to find a solution with different components to the existing design, or find a sensor with similar function that could replace the previous design of the sensor finger.</p><p>Our work has been limited by ESAB due to the user friendly mechanical design of the previous sensor finger. After examining different sensors we choose to use strain gages as sensors for the mechanical sensor finger. With this choice we also needed to suggest a theoretical design for a mechanical attachment of the sensor finger.</p><p>We have designed two separate Wheatstone bridges with separate instrumental amplifiers (INA125). The output signals from the bridges are relatively small and need to be amplified around 2000 times.</p><p>The zero balancing of the bridges has been done manually with potentiometers but we have also suggested a solution where the zero balancing can be performed by a push-button. The button is placed where you cannot push it unintentionally.</p><p>The result of this degree project is a circuit on a veroboard, a designing proposal for the attachment and the sensor finger.</p><p>In order to further develop this design it would be necessary to build a prototype to evaluate its life span and find the optimal sensitivity.</p>

This diploma thesis contains an engineering design of a two-stroke engine for small motorcycle. In the first part, the background research of these motors was made. Main dimensions of the engine and a calculation of the forces acting in crank mechanism were determined. Further check stress analysis of connection rod and calculation using a finite element method were performed. This diploma thesis also includes virtual 3D models of all designed parts and a drawing of cross section of the motor.

This study has been conducted at Scania Engine Assembly, in particular in an production area that produces Marine Engines. Scania always strives for continuous improvement and the purpose of this study has been to create an overview of the production area Marine-completion, where the marine components are assembled. The goals were to create a current state analysis, propose a future state analysis and propose suggestions of solutions for improvement of Marine-completion. The research question was: How can the strategies for the current state analysis be chosen, used and analyzed in order to accomplish a successful current state analysis?. The research methodology in this study was conducted using qualitative and quantitative research strategies, where both primary and secondary data were collected. The theoretical framework was divided into four subsections: Production systems, project management, technical solutions of today and supporting literature for solutions. The main method of this study was collecting data. The data included layout of the production, assembly times, quality deviations, engine variant classifications, Value Stream Mapping, Safety, Health and Environment related deviations and costs. Based on the current state, a future state was developed. The results of the current state analysis was that there are a total of 20 main variants of marine engines which have different assembly times. The assembly time can vary from approximately 45 minutes to 3 hours and 35 minutes for straight engines and approximately 4 hours to 8 hours for V8 engines. The mean results from Value Stream Mapping concluded a distribution of 40 percentage Value Adding and 60 percentage Non-Value Adding, where the largest waste from Non-Value Adding activities was bringing parts. Most of the quality deviations were caused by the method, where the biggest problem was regarding "tool insufficiency". Safety, Health and Environment related deviations were identified, where the largest problems were "risk". The future state analysis ended up in three cases, which explains the possible savings and future states. The Failure Mode and Effects Analysis resulted in 7 failure modes, where "Engine-card missing tasks/parts" had the largest rating. The suggestion of solutions resulted in a new layout, new routines with the engine-cards with digital screens and some other smaller suggestions. This study concluded in three main suggestions of solutions about "Newlayout at Marine-completion ", "Digital screens at each station" and "Continuous update of enginecards", which resulted in three assignment directives that Scania can further work with in the future.<br>Detta arbete har utförts på ett produktionsområde i Scanias motormontering i Södertälje, Stockholm. Scania strävar alltid mot ständiga förbättringar och detta arbete uppfyller det genom syftet att skapa en kartläggning över produktionsområdet med fokus i förbättringar. Målen med detta arbete var att kartlägga nuläget i Marinkompletteringen samt skapa ett framtidsläge tillsammans med föreslagna förbättringsförslag. Den forskningsrelaterade frågeställningen för detta arbete var: Hur kan strategierna för nulägesanalysen väljas, användas och analyseras för att uppnå en lyckad nulägesanalys? Metoden för litteraturstudien som utförts för detta arbete använde kvalititativa och kvantitiva forskningsmetoder där både primär och sekundärdata samlades. Det teoretiska ramverket var uppdelat i fyra delkapitel: Produktionssystem, projektledning, tekniska lösningar idag och stödjande litteratur för lösningar. Huvudmetoden för detta arbete var datainsamlingen som inkluderade aspekter som layout på området, monteringstider, kvalitetsavvikelser, motorvarianternas klassificering, värdeflödesanalys, avvikelser kopplat till säkerhet, hälsa, miljö och kostnader. Utifrån nulägesanalysen utvecklades framtidsläget fram. Resultaten från nulägesanalysen påvisade en total mängd av 20 olika huvudvarianter på marinmotorerna som monteras i marinkompletteringen med olika monteringstider. Monteringstiderna kunde sträcka sig mellan 45 minuter till tre timmar och 35 minuter för raka motorer och ungefär fyra till åtta timmar när det gäller V8 motorer. Medelvärdet på resultatet av värdeflödesanalysen resulterade i en fördelning av 40 procent värdeskapande tid och 60 procent icke-värdeskapande tid där det största slöseriet tillkom vid upphämtning av artikel. De flesta kvalitetsbristerna orsakades av metodiska fel där det mest förekommande metodiska felet var framkomlighet för verktyg. Bristerna kring säkerhet, hälsa och miljö identifierades och den mest förekommande bristen var gällande risker på arbetsplatsen. Analysen av framtidsläget resulterade i tre scenarion som vardera förklarar möjliga kostnadsbesparingar vid utfasning av olika icke-värdeskapande aktiviteter. Failure Mode and Effects Analysis som utfördes resulterade i sju feltyper varav "brist på information i motorkort" hade högst risktal. Rekommenderade åtgärder för Failure Mode and Effects Analysis resulterade i förslag om ny layout, nya rutiner gällande motorkort med digitala lösningar samt ett flertal mindre lösningar. De föreslagna lösningar som gavs till Scania i detta arbete var tre konkreta huvudförslag angående "ny layout på marinkompletteringen", "digitala skärmar på vardera station" och "kontinuerlig uppdatering av motorkort" vilket i sin tur resulterade i tre uppdragsdirektiv som Scania fortsatt kan jobba med i framtiden.

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.

Possible modern application of piston steam engine is electricity production using steam made by solar energy. This diploma thesis focuses on designing such piston steam engine Described solution would be effective as an off grid electricity generator, because alternative source of steam could be added for occasions, when sunlight is not powerfull enough for steam production.

This diploma thesis includes progress constructional design of 2 - stroke engine for small mechanization, using modern tools of computer aided design. In the first part is mentioned short summary contemporary types small mechanization with 2 - stroke engines. Follows part devoted conceptual design with calculation of the main dimensions of engine cylinder. After assesment strength load of cranked mechanism, is effected stress analysis of connection rod, whose design and modeling is part of work, how by the help of analytical figures from appropriate literature so by final element method. Last part of those work is estimation results with presentation parameters, which affect power of 2 - stroke engines for small mechanization.

Die Option Mechanism Dynamics (MDO) von Creo Parametric ist ein Tool aus dem Bereich Starrkörperdynamik. Im Kern des Vortrags steht jedoch die MDO-Funktion 3D-Kontakt, die einzigartig mit elastischen Körpern arbeitet. Im Vortrag wird die Vorgehensweise bei der dynamischen Simulation eines Rutschreifens auf GFK-Wasserrutschen erläutert, abschließend werden Animationsbeispiele präsentiert.

The purpose of this diploma thesis is comparing the quantity of porosity in die-cast aluminium casting with using simulation. The cast engine blocks were made by high pressure die-casting and a local squeeze casting (LSC) technology. There was also examined the relationship between porosity and mechanical properties of castings. There were evaluated and compared the results of my own measurements with data from previous students theses at the Faculty of Mechanical Engineering BUT. All data were tested by statistical tests. The comparison of simulation results and experimentally measured values was found a good programme-ability to simulate and estimate porosity.

The goal of this master’s thesis is to examine the influence of eccentricity on the behaviour of forces between the piston and cylinder liner and on balancing of the crank mechanism for given parameters of the diesel engine. Another aim of this paper is to propose an appropriate balancing of the crank mechanism followed by stress analysis considering torsional vibration for a chosen value of eccentricity.

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.

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.

The purpose of this thesis is to evaluate the influence of eccentricity of crank mechanism to the force between the piston and the cylinder liner for appointed crank mechanism. Furthermore the influence of eccentricity to balancing crankshaft is verified and for selected value of eccentricity is realized balance. For the construction check was realized stress analysis of crank mechanism included torsion vibration.

The present diploma thesis deals with innovation of built-up crankshaft of Blata minibikes. Minibike is the type of a small two-stroke motorcycle equipped with an internal combustion engine of the volume 40 or 50 cm3. The machine is designed for racing circuits; not only for young riders but also for seniors. The innovation is in the design and verification of pressed connections in the imposition of major pins in the arms of the crankshaft. Pressed connections are designed on the basis of the analysis of force interaction on the crankshaft at maximum revolutions. The proposed solutions are verified by FEM calculations. Based on the results, the best option is selected. For the selected option, the impact of force interaction at maximum machine performance is studied. Finally, on the basis of these facts, designing, technological and economic analysis of feasibility of new production technology is carried out.

The aim of this diploma is to design a crankshaft for a six-cylinder commercial vehicle, which is one of the unified motors. The main parts are the design of the crankshaft configuration, the crankshaft balancing method for forces and moments, the crankshaft design documentation, and the crankshaft strength verification. The design of torsional vibration damping characteristics is also made and its effect on torsional vibration and crankshaft strength is determined.

[ES] Con el aumento de la demanda de soluciones más amigables con el medio ambiente en la industria de la automoción, el motor de combustión interna alternativo (MCIA) enfrenta actualmente grandes desafíos para minimizar su consumo de recursos no renovables y especialmente, para reducir sus emisiones contaminantes. Debido a que el aporte de los MCIAs es fundamental para cubrir las necesidades de movilidad y de generación de energía alrededor de todo el mundo, y el hecho de que diferentes alternativas, como los motores eléctricos e hibrido, están y continuaran enfrentado múltiples obstáculos para su implementación masiva en el futuro cercano, la investigación continua en MCIA es fundamental para cumplir con los propósitos de reducción de emisiones. En este aspecto, una aproximación para el aumento de la eficiencia del motor y la reducción del consumo de combustible es mediante la implementación de alternativas dirigidas a reducir las pérdidas mecánicas por fricción. Estas alternativas tribológicas incluyen aquellas que requieren modificaciones en los componentes del motor, como materiales y acabados superficiales, y el uso de formulaciones de aceite lubricante de menor viscosidad o aditivos que mejoren las condiciones de lubricación del motor. Con la contante evolución y mejoras en el MCIA y las condiciones de trabajo cada vez más severas, también surgen nuevas alternativas tribológicas para enfrentar los nuevos desafíos del motor, y por tanto se requiere de investigaciones adicionales en este tema. Durante el desarrollo de esta Tesis, uno de los objetivos consistió en contribuir a la investigación del uso de aceites de baja viscosidad para el ahorro de combustible como un efecto conjunto con las condiciones de conducción del vehículo. Para llevar a cabo este objetivo, se desarrollaron ensayos experimentales bajo condiciones estacionarias en un banco de motor con formulaciones de aceite de diferente viscosidad HTHS, algunas de ellos con aditivo modificador de fricción para expandir el rango de reducción de fricción a condiciones de lubricación más severas. Los mapas de consumo de combustible resultantes de estos ensayos fueron utilizados en un modelo de simulación del vehículo para estimar su consumo de combustible como función del aceite y las condiciones de trabajo de tres ciclos de conducción. Con el objetivo de expandir los conocimientos en los fundamentos de lubricación de los MCIAs y tener la capacidad de evaluar otras alternativas para reducir las pérdidas por fricción, se consideró necesario enfocar la investigación en el conjunto pistón-camisa, que es el par tribológico con mayor aporte a las perdidas por fricción. Para conseguir este objetivo, durante esta Tesis se desarrolló una maqueta específica para el ensamble pistón-camisa, y un modelo teórico para simular la lubricación del segmento de compresión. Para la primera parte, la maqueta se desarrolló basada en el método de camisa flotante, en el cual la camisa fue aislada del resto del motor y la fuerza de fricción generada en la interfaz pistón-camisa pudo ser medida mediante sensores de fuerza. En esta instalación se desarrollaron diferentes ensayos los cuales permitieron llevar a cabo un análisis exhaustivo de los fundamentos de lubricación de este par tribológico como función de diferentes parámetros que tiene impacto en las condiciones de lubricación. Este estudio se complementó con el desarrollo de un modelo de lubricación para el segmento de compresión basado en el método de diferencias finitas. Finalmente, se llevó a cabo una comparativa de resultados experimentales y teóricos para el segmento de compresión, lo cual permitió validar los ensayos experimentales en la maqueta de camisa flotante, así como el modelo de simulación desde el punto de vista de datos de entrada, condiciones de contorno y supuestos.<br>[CA] Amb l'augment de la demanda de solucions més amigables amb el medi ambient en la indústria de l'automoció, el motor de combustió interna alternatiu (MCIA) s'enfronta actualment a grans desafiaments per minimitzar el seu consum de recursos no renovables i especialment, per reduir les seves emissions contaminants . Tenint en compte que l'aportació dels MCIA és fonamental per a cobrir les necessitats de mobilitat i generació d'energia arreu de tot el món, i el fet que diferents alternatives, com els motors elèctrics i híbrids, estan i continuaran enfrontat múltiples obstacles per a la seva implementació massiva al proper futur, la investigació contínua en MCIA és fonamental per complir amb els propòsits de reducció d'emissions. En aquest aspecte, una aproximació per a l'augment de l'eficiència del motor i la reducció de consum de combustible és mitjançant la implementació d'alternatives dirigides a reduir les pèrdues mecàniques per fricció. Aquestes alternatives tribològiques inclouen aquelles que requereixen modificacions de components del motor, com materials i acabats superficials, i l'ús de formulacions d'oli lubricant de menor viscositat o additius que milloren les condicions de lubricació del motor. Amb la constant evolució i millores en el MCIA i les condicions de treball cada vegada més severes, també sorgeixen noves alternatives tribològiques per enfrontar els nous desafiaments del motor, i per tant es requereix d'investigacions addicionals en aquest tema. Durant el desenvolupament d'aquesta Tesi, un dels objectius va consistir a contribuir a la investigació de l'ús d'olis de baixa viscositat per a l'estalvi de combustible com un efecte conjunt amb les condicions de conducció de vehicle. Per dur a terme aquest objectiu, es van desenvolupar assajos experimentals sota condicions estacionàries en un banc de motor amb formulacions d'oli de diferent viscositat HTHS, algunes d'elles amb additiu modificador de fricció per expandir el rang de reducció de fricció a condicions de lubricació més severes . Els mapes de consum de combustible resultants d'aquests assajos van ser utilitzats en un model de simulació del vehicle per estimar el seu consum de combustible com a funció de l'oli i les condicions de treball de tres cicles de conducció. Amb l'objectiu d'expandir els coneixements en els fonaments de lubricació dels MCIAs i tenir la capacitat d'avaluar altres alternatives per reduir les pèrdues per fricció, es va considerar necessari enfocar la recerca al conjunt pistó-camisa, que és el parell tribològic amb major aportació a les perdudes per fricció. Per aconseguir aquest objectiu, durant aquesta Tesi es va desenvolupar una maqueta específica per al acoblament pistó-camisa, i un model teòric per simular la lubricació del segment de compressió. Per a la primera part, la maqueta es va desenvolupar basada en el mètode de camisa flotant, en el qual la camisa va ser aïllada de la resta del motor i la força de fricció generada en la interfície pistó-camisa va poder ser mesurada mitjançant sensors de força. En aquesta instal·lació es van desenvolupar diferents assajos els quals van permetre dur a terme una anàlisi exhaustiva dels fonaments de lubricació d'aquest parell tribològic com a funció de diferents paràmetres que tenen impacte en les condicions de lubricació. Aquest estudi es va complementar amb el desenvolupament d'un model de lubricació per al segment de compressió basat en el mètode de diferències finites. Finalment, es va dur a terme una comparativa de resultats experimentals i teòrics per al segment de compressió, la qual cosa va permetre validar els assajos experimentals a la maqueta de camisa flotant, així com el model de simulació des del punt de vista de dades d'entrada, condicions de contorn i hipòtesis.<br>[EN] With the increasing demand for greener solutions in the automotive industry, the ICE is currently facing great challenges to minimize the consumption of nonrenewable resources and specially to reduce its harmful emissions. Given that the contribution of the ICE is fundamental to cover the actual mobility and power generation needs worldwide, and the fact that different power-train alternatives, such as electric and hybrid vehicles, are and will continue facing multiple obstacles for their large-scale implementation in the near future, the continuous research on the ICE is fundamental in order to meet the emissions reduction targets. In this regard, one approach to increase the engine efficiency and reduce the fuel consumption, is through the implementation of alternatives aimed to reduce the friction mechanical losses. These tribological alternatives include those that require modifications to the engine components, such as materials and surface finishes, and the use of lubricant oil formulation of lower viscosity or additives that improve the lubrication performance of the engine. With the ongoing evolution and improvement of the ICE and the increasingly severe working conditions, new tribological solutions also emerge to face the new challenges in the ICE, and therefore further research is required on this subject. During the development of this Thesis, one of the objectives was to contribute to the research on low viscosity engine oils for fuel economy as a joint effect with the driving conditions of the vehicle. To accomplish this, experimental tests were performed under stationary conditions in an engine bench test for oil formulations of different HTHS viscosity, some of them with friction modifier additive to expand the friction reduction effect to more severe lubrication conditions. The resultant fuel consumption maps were then employed in a vehicle model to estimate the fuel consumption of the vehicle as function of the oil formulation and the working conditions of the three driving cycles. With the aim of expanding the knowledge on the lubrication fundamentals of the engine and to have the capability to assess other alternatives to further reduce the friction mechanical losses, it was deemed necessary to focus the research on the piston-cylinder liner assembly, the tribo-pair of major friction share. In order to achieve this objective, a test rig was developed in this Thesis specific for the piston-liner assembly, and a theoretical model to estimate the lubrication of the piston compression ring. For the first part, the test rig was designed based on the floating liner method, where the cylinder liner was isolated from the rest of the engine and the friction force generated in the piston-liner conjunction could be measured by means of force sensors. Different tests were developed in this test rig which allowed a comprehensive analysis of the piston lubrication fundamentals as function of different parameters having an impact on the lubrication performance of this assembly. This study was complemented with the development of a piston compression ring lubrication model based on the finite differences method. A comparison of experimental and theoretical results was performed for the piston compression ring that helped to validate both the experimental tests in the floating liner and the simulation model from the point of view of input data, boundary conditions and assumptions.<br>Bastidas Moncayo, KS. (2021). Experimental and analytical study of the mechanical friction losses in the piston-cylinder liner tribological pair in internal combustion engines (ICE) [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172188<br>TESIS

O controle de emissões em veículos pesados está em foco desde a década de 90, com a criação de regulamentações nacionais e internacionais que impõe limites cada vez mais rígidos para as concentrações de poluentes emitidos por estes veículos. O desenvolvimento de novas tecnologias possui papel fundamental neste processo, buscando redução nos níveis de emissões com mínimo impacto negativo no desempenho e no consumo do veículo. Para tanto, o presente trabalho visa avaliar a influência da posição dos dutos de admissão de ar de cabeçotes de motores a combustão interna, especificamente em motores de ignição por compressão (MIC) de 4 válvulas, no escoamento de ar dentro do cilindro. O escoamento do ar e o movimento de swirl são fatores importantes para a mistura e distribuição do combustível injetado, e quando otimizados para uma queima melhor distribuída, contribuem para redução nos níveis de emissões. Procura-se investigar quais direções características dos dutos são determinantes para o escoamento e para o comportamento de swirl do motor através de simulações em fluidodinâmica computacional (Computational Fluid Dynamics - CFD) utilizando o programa CD-adapco STAR-CCM+®. Os resultados de alguns dos cenários simulados são comparados a resultados de testes experimentais realizados em bancada de medição de swirl, no âmbito de outro trabalho sendo desenvolvido no mesmo grupo de projeto.<br>The emissions control in heavy-duty vehicles has been in focus since the 1990\'s, with the creation of national and international regulations which impose strict limits for pollutant concentrations released by these vehicles. The development of new technologies has a fundamental role in this process, aiming the reduction of emission levels with minimum impact on the performance and fuel consumption of the vehicle. Therefore, the present study aims to evaluate the influence of the position of intake ports in cylinder heads from internal combustion engines, specifically 4-valves compression-ignition (CI) engines, in the in-cylinder air flow. The air flow and swirl motion are important factors for the mixture and distribution of injected fuel, and when optimized for a better distributed combustion, contribute for the reduction of emission levels. This study investigates the characteristic directions of ports which are determinant for the air flow and swirl behaviour of the engine through Computational Fluid Dynamics (CFD) simulations using CD-adapco software STAR-CCM+®. The results from a group of simulated cases are compared to experimental test results from another project, developed on the same project group, performed in a swirl meter test rig.

This thesis deals with the construction of drives for self-supporting gates. The main parts from which the drive is folded are not discussed here. In addition, the main points of load are solved which arise on the self-supporting gate and it´s contact with the guiding, carrying carts and movement elements. And here is explained what needs to be taken care of by the drive to accommodate the loads, which all aggravate the movement of the structure. in the work are also presented the load types of load calculations by which the drive parameters can be checked for suitability for the application.

Turbocharged spark-ignited engines may encounter stochastic events of premature ignition of the fuel-air mixture, termed as pre-ignition. Pre-ignition often leads to extremely high peak pressure and pressure oscillations, causing engine damage. A review of pre-ignition in historic times is done in this dissertation, and the similarities and differences compared to modern pre-ignition issue are brought forth. Experiments conducted with varying injection strategies yielded varying pre-ignition tendency. The pre-ignition tendency correlated with the charge cooling tendency and the mass of liquid fuel impinging on the cylinder liner and diluting the oil film. The diluted oil is trapped in the piston ring area and from time-to-time gets launched into the combustion chamber near top dead center. The fuel-oil mixture droplet may ignite the surrounding charge before the spark timing. Experiments conducted with varying exhaust back pressure showed dependence of pre-ignition tendency on in-cylinder temperature near top dead center, for cases when intake pressure is higher than exhaust pressures. For exhaust pressure higher than intake pressure, fuel wall impingement was critical to pre-ignition. This research also devised ion-current based sensors for pre-ignition detection. Initial experiments were done with DC-power based ion-current sensor, which detected a pre-ignition event when a flame brushed past the sensor. There was a need of faster-response sensor with high signal-to-noise ratio, that would allow pre-ignition detection at its inception stage, thereby giving enough time to trigger an evasive action. In this regard, an AC-powered ion-current sensor was devised and patented. Sudden fuel enrichment at the time of pre-ignition detection was investigated as an evasive method. Various strategies were investigated for their pre-ignition suppression tendency. Split injection, water injection, Octane-on-Demand, injecting different fluids in late compression stroke and dual fuel operation with gasoline and methane were found to be highly effective at suppressing pre-ignition completely. Use of ethanol in blends with different FACE gasolines is investigated to suggest fuel effects on pre-ignition. The strategies were successful at either reducing the mass of liquid fuel impinging the liner, reducing the in-cylinder temperature near top dead center or reducing the potential of residual gas content to trigger pre-ignition in the next cycle.

Researchers have offered a variety of solutions for overcoming the old and challenging problem of undesired vibrations. The optimum vibration-control solution that can be a passive, semi-active or active solution, is chosen based on the desired level of vibration-control, the budget and the nature of the vibration source. Mechanical vibration-control systems, which work based on variable stiffness control, are categorized as semi-active solutions. They are advantageous for applications with multiple excitation frequencies, such as seismic applications. The available mechanical variable stiffness systems that are used for vibration-control, however, are slow and usually big, and their slowness and size have limited their application. A new semi-active variable stiffness solution is introduced and developed in this thesis to address these challenges by providing a faster vibration-control system with a feasible size. The new solution proposed in this thesis is a semi-active variable stiffness mount/isolator called the antagonistic Variable Stiffness Mount (VSM), which uses a variable stiffness spring called the Antagonistic Variable stiffness Spring (AVS). The AVS is a kinematically singular prestressable mechanism. Its stiffness can be changed by controlling the prestress of the mechanisms links. The AVS provides additional stiffness for a VSM when such stiffness is needed and remains inactive when it is not needed. The damping of the VSM is constant and an additional constant stiffness in the VSM supports the deadweight. Two cable-mechanisms - kinematically singular cable-driven mechanisms and Prism Tensegrities - are developed as AVSs in this thesis. Their optimal configurations are identified and a general formulation for their prestress stiffness is provided by using the notion of infinitesimal mechanism. The feasibility and practicality of the AVS and VSM are demonstrated through a case study of a typical engine mount by simulation of the mathematical models and by extensive experimental analysis. A VSM with an adjustable design, a piezo-actuation mechanism and a simple on-off controller is fabricated and tested for performance evaluation. The performance is measured based on four criteria: (1) how much the VSM controls the displacement near the resonance, (2) how well the VSM isolates the vibration at high frequencies, (3) how well the VSM controls the motion caused by shock, and (4) how fast the VSM reacts to control the vibration. For this evaluation, first the stiffness of the VSM was characterized through static and dynamic tests. Then performance of the VSM was evaluated and compared with an equivalent passive mount in two main areas of transmissibility and shock absorption. The response time of the VSM is also measured in a realistic scenario.