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Dissertations / Theses on the topic 'Motor cycle'
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Koerner, Stephen. "The British motor cycle industry, 1935-1975." Thesis, University of Warwick, 1995. http://wrap.warwick.ac.uk/2614/.
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Between 1935 and 1975, the British motor cycle industry declined from world supremacy to bankruptcy. The industry blamed its troubles on government policy, specifically taxation and regulation. These, it was maintained, had weakened and manufacturers' ability to effectively meet foreign competition, particularly after 1960 from Japan. The existing historiography has identified boardroom mismanagement as the main culprit. However, what the literature lacks is a wider perspective, especially one which extends to the period before 1945. Those years are critical to understanding the nature of the industry. This dissertation provides such a perspective combined with an analysis based on extensive primary research, particularly amongst recently opened trade and company records, as well as government documents at the Public Records Office. Although no single factor was entirely responsible for the industry's downfall, this dissertation will offer several explanations of varying importance. The failure to develop a cheap, lightweight motor cycle is particularly significant. This, in turn, reflected a 'management culture' which prevailed within many company boardrooms. The 'culture' was closely related to and influenced by a deep seated dedication to motor cycle sport and resulted in a narrow view of the market and the 'typical' consumer, both in Britain and abroad.
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Blaha, Josef. "Stirlingův motor." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228037.
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This dissertation discusses Stirling’s cycle and its contribution using different approaches. There are calculation of Schmidt’s theory and distinctiveness between ideal and real cycle described. Based on my previous research, this work provides a detailed summary of different methods which are used to stimulate Stirling’s cycles as well as the motor as a whole. Attention is particularly dedicated to current utilization of this machine which is not broadly known within general public.
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Filipi, Jaroslav. "Mechanismus jednoválcového vznětového motoru s prodlouženou expanzí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229170.
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The diploma thesis deals with mechanism of combustion motor that enables greater expansion ratio then compression ratio. The main advantage of motor mechanism is verified in thesis, which is greater thermal efficiency then compared to conventional diesel motor. Additionally, there are investigation of kinematic variables, force of gas pressure and inertia forces, which operates in different bindings mechanism. The last part deals witch strength of selected parts of the proposed mechanism.
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Schumann, Benjamin. "Aeronautical life-cycle mission modelling framework for conceptual design." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366537/.
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This thesis introduces a novel framework for life cycle mission modelling during conceptual aeronautical design. The framework supports object-oriented mission definition using Geographical Information System technology. Design concepts are defined generically, enabling simulation of most aeronautical vessels and many non-aeronautical vehicles. Moreover, the framework enables modelling of entire vessel fleets, business competitors and dynamic opera-tional changes throughout a vessel life cycle. Vessels consist of components deteriorating over time. Vessels carry payload that operates within the vessel environment. An agent-based simulation model implements most framework features. It is the first use of an agent-based simulation utilising a Geographical Information System during conceptual aero-nautical design. Two case studies for unmanned aircraft design apply the simulation. The first case study explores how the simulation supports conceptual design phase decisions. It simulates four different unmanned aircraft concepts in a search-and-rescue scenario including lifeboats. The goal is to learn which design best improves life cycle search performance. It is shown how operational and geographical impacts influence design decision making by generating novel performance information. The second case study studies the simulation optimisation capability: an existing aircraft design is modified manually based on simulation outputs. First, increasing the fuel tank capacity has a negative effect on life cycle performance due to mission constraints. Therefore, mission definition becomes an optimisation parameter. Changing mission flight speeds during specific segments leads to an overall improved design.
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Koštuřík, Vojtěch. "Zážehový pístový spalovací motor s prodlouženou expanzí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377469.
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This thesis deals with the design of a spark-ignition internal combustion engine with extended expansion. It explains the principle of extended expansion using the Atkinson or Miller cycle and the possibilities of achieving it. In addition, a design study and engine cycle is carried out. Subsequently, the course of the kinematic quantities and forces in the mechanism is determined. At the end, the strength analysis of the connecting rod of the designed mechanism is performed.
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Bergman, David. "Quantification of Drive Cycles for Evaluating Motor Efficiency." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-451235.
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Due to the goals made by the European Union as well as the country of Sweden regarding the desired decrease of the ongoing greenhouse gas emissions, electrical alternatives have increased enormously in the industry and the automotive areas in recent years. By going from petrol-powered vehicles to electrical vehicles, the transport sector has the potential to produce zero direct emissions. To be able to develop electrical vehicles with the highest efficiency possible, it is of great importance to understand what losses occurs in the vehicle. By lowering these losses, we create a vehicle which both become cheaper and better for the climate. The aim of his thesis is to study the performance of the motors with different combinations of angular velocity and torque, analyse what losses occur with the combinations and also how the result is affected by the resolution of the drive cycles. Produced drive cycles, with a purpose to represent the velocity and acceleration of a vehicle in a realistic way, was used during the study to obtain a drive pattern. MATLAB was used during the whole thesis for analysis, simulation and plotting. Firstly, a method to obtain the probability of certain combinations of torques and angular velocities for a specific drive cycle was created. With this probability, a method to be able to adjust and choose the resolution of the torques and angular velocities was created. It was later concluded that these two methods functioned as desired. With the obtained combinations, the mechanical power as well as the most common losses in the electrical motor could be calculated. With this, an efficiency could be calculated and analysed. The energy demand of the different combinations was also obtained. One conclusion that could be made with this thesis was that the average efficiency did not depend on the resolution of the torque and angular velocity much at all. With a resolution going from 0.5 Nm to 20 Nm, the average efficiency only changed by below 0.3 percent units. At the end of the thesis, a continued work is proposed to implement different magnetic properties that are not accounted for in this thesis. Another suggestion made is to include scenarios where the battery is charged when a negative torque is applied to the motor shaft.
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Sedighi, Alireza. "Applications of Motor Variability for Assessing Repetitive Occupational Tasks." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77947.
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The human body has substantial kinetic and kinematic degrees-of-freedoms, so redundant solutions are available for the central nervous system (CNS) to perform a repetitive task. Due to these redundancies, inherent variations exist in human movement, called motor variability (MV). Current evidence suggests that MV can be beneficial, and that there is an inverse association between MV and risk of injury. To better understand how the CNS manipulates MV to reduce injury risks, we investigated the effects of individual differences, task-relevant aspects, and psychological factors as modifiers of MV. Earlier work found that experienced workers adapted more stable movements than novices in repetitive lifting tasks. To expand on this, we quantified how MV differs between experienced workers and novices in different lifting conditions (i.e., lifting asymmetry and fatigue). Three different measures (cycle-to-cycle SD, sample entropy, and the goal equivalent manifold) were used to quantify MV. In a symmetric lifting task, experienced workers had more constrained movement than novices, and experienced workers exhibited more consistent behavior in the asymmetric condition. Novices constrained their movements, and could not maintain the same level of variability in the asymmetric condition. We concluded that experienced workers adapt stable or flexible strategies depending on task difficulty. In a prolonged lifting task, both groups increased their MV to adapt to fatigue; they particularly increased variability in a direction that had no effects on their main task goal. Developing fatigue also makes it difficult for individuals maintain the main goal. Based on these results, we conclude that increasing variability is an adaptive strategy in response to fatigue. We also assessed variability in gait parameters to compare gait adaptability using a head-worn display (HWD) compared with head-down displays for visual information presentation. An effective strategy we observed for performing a cognitive task successfully during walking was to increase gait variability in the goal direction. In addition, we found that head-up walking had smaller effects on MV, suggesting that HWDs are a promising technology to reduce adverse events during gait (e.g., falls). In summary, these results suggest that MV can be a useful indicator for evaluating some occupational injury risks.Ph. D.
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Magee, Samuel John. "Investigation of the performance and emissions characteristics of small capacity two-stroke cycle engines." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388072.
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Russell, Bernard. "The trend to standardization : product development in the British motor cycle industry 1896-1916." Thesis, City University London, 1985. http://openaccess.city.ac.uk/14789/.
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The thesis is a historical study of the first twenty years of the British motor cycle industry in terms of the development of its product. The main theoretical issue is standardization, not in its usual sense as a forma l activity aimed at the setting up of standards, but as a trend the effect of which is for products to become more and more alike across the industry as a whole. Standardization in this sense is to a large extent an unintended consequence of the wish on the part of producers to design products which operate more efficiently, which can be produced more cheaply, and which have the widest possible appeal in the marketplace; and of the preference, on the part of the majority of consumers, for products which are familiar and of known reputation and performance, as against those which are new and untried. The trend to standardization is analysed into its main components , functional efficiency, production efficiency, and marketing efficiency, and these are used as the basis of a number of propositions which make it possible to consider in more depth the development of the product during the three phases of industry development : experimental, developmental, and standardization . The more substantive chapters of the thesis are organized around three main themes, the development of the industry as a whole, and the development of the product from a technical point of view, and from a consumer point of view. The main conclusion is that the development of its product into a standard form--one on which newcomers to the industry can base their own products and which consumers can recognise as reliable and worthy of purchase-is the most critical stage in the development and consolidation of a new industry.
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Shoukry, Ehab F. "Numerical simulation for parametric study of a two-stroke compression ignition direct injection linear engine." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3071.
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Thesis (Ph. D.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xxvii, 166 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 121-126).
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Gibble, John Curtis. "Comparison of heavy-duty diesel engine emissions between an on-road route and engine dynamometer simulated on-road cycle." Morgantown, W. Va. : [West Virginia University Libraries], 2003. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3016.
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Thesis (M.S.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xi, 101 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 72-76).
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Lee, Jeongwoo. "Rotating Inertia Impact on Propulsion and Regenerative Braking for Electric Motor Driven Vehicles." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/30803.
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A vehicle has several rotating components such as a traction electric motor, the driveline, and the wheels and tires. The rotating inertia of these components is important in vehicle performance analyses. However, in many studies, the rotating inertias are typically lumped into an equivalent inertial mass to simplify the analysis, making it difficult to investigate the effect of those components and losses for vehicle energy use. In this study, a backward-tracking model from the wheels and tires to the power source (battery or fuel cell) is developed to estimate the effect of rotating inertias for each component during propulsion and regenerative braking of a vehicle. This paper presents the effect of rotating inertias on the power and energy for propulsion and regenerative braking for two-wheel drive (either front or rear) and all-wheel drive (AWD) cases. On-road driving and dynamometer tests are different since only one axle (two wheels) is rotating in the latter case, instead of two axles (four wheels). The differences between an on-road test and a dynamometer test are estimated using the developed model. The results show that the rotating inertias can contribute a significant fraction (8 -13 %) of the energy recovered during deceleration due to the relatively lower losses of rotating components compared to vehicle inertia, where a large fraction is dissipated in friction braking. In a dynamometer test, the amount of energy captured from available energy in wheel/tire assemblies is slightly less than that of the AWD case in on-road test. The total regenerative brake energy capture is significantly higher (> 70 %) for a FWD vehicle on a dynamometer compared to an on-road case. The rest of inertial energy is lost by inefficiencies in components, regenerative brake fraction, and friction braking on the un-driven axle.Master of Science
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Wang, Shiyi. "Motor vehicle air-conditioning : utilising the exhaust gas energy to power an absorption refrigeration cycle." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/9577.
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Includes bibliographical references.It is a well-known fact that a lot of heat energy associated with the exhaust gases from an engine is wasted. The work described in this thesis attempts to use the energy from the motor car's exhaust gases to power an air-conditioning system. Thus the waste heat can be utilised and shaft power conserved by replacing the traditional compression refrigeration system, used for air-conditioning a motor car, with an absorption unit. The thesis deals with some theoretical aspects of the absorption refrigeration cycle as well as practical aspects of motor car air-conditioning. A fair amount of research on absorption refrigeration has concentrated on the choice of the combinations absorbent and refrigerant. The need for the combination to be suitable for this special application is self evident. The use of aqua-ammonia, one of the oldest and most widely used combinations for absorption refrigeration systems, to chill water which is used as a secondary fluid, goes a long way in ensuring that ammonia does not get released in the passenger space. An added bonus is that this choice of refrigerant does not have potentially an adverse environmental influence (i.e. ozone layer etc.).
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Dúlovcová, Gabriela. "Návrh vačkového hřídele pro motor s Millerovým cyklem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417424.
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The main aim of this thesis is the analysis of influence of inlet valve opening length and compression ratio on performance and thermodynamic parameters of Miller cycle using GT-SUITE software. Next step was an optimization of inlet and exhaust valve timing with goal of increasing motor effective power. For chosen option was designed cam shaft with regard of kinematic and dynamic magnitude courses.
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Thokala, Praveen. "Life cycle cost modelling as an aircraft design decision support tool." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/72021/.
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This report summarizes the work that has been carried out as part of the FLAVIIR project, a 5 year research program looking at technologies for future unmanned air vehicles. A novel classication of aircraft product defnition is utilised and a framework to estimate the life cycle cost of aircraft using the product definition is presented. The architecture to estimate the life cycle cost and the associated models are described. The acquisition costs are estimated using a hierarchical structure and a discrete simulation model is used to estimate the maintenance and operation costs. The acquisition cost model uses an object oriented approach with libraries of materials and processes integrated into the cost model. Risk analysis is performed to identify the important design parameters and uncertainty in the model. The acquisition cost model developed has the capability to estimate the costs of aircraft structures manufactured using metal-based materials as well as non-metal-based materials. The discrete event simulation model estimates the operation and maintenance costs of a fleet of aircraft using the mission characteristics, aircraftperformance and the logistics data as input. The aircraft performance parameters are calculated by using aerodynamic analysis along with performance analysis models and the simulation model utilises a novel methodology to link aircraft performance with survivability analysis for estimating the maintenance costs. A framework is presented in which the cost models developed can be integrated into the conceptual design process to facilitate the comparison between different configurations. The usage of the life cycle cost framework as a decision support tool is outlined and three case studies are presented which include composites vs metals trade-off analysis, optimisation studies and web deployment for real time cost estimation. The novel contributions of this research are outlined and interesting avenues for future research that can be pursued are identified.
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Li, Ying. "DEFINING MURINE RETROVIRAL COMPONENTS AND VIRAL LIFE CYCLE EVENTS REQUIRED FOR INDUCING SPONGIFORM MOTOR NEURON DEGENERATION." Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1216423317.
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Jaster, Nicole. "Ratchet models of molecular motors." Phd thesis, Universität Potsdam, 2003. http://opus.kobv.de/ubp/volltexte/2005/90/.
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Transportvorgänge in und von Zellen sind von herausragender Bedeutung für das Überleben des Organismus. Muskeln müssen sich kontrahieren können, Chromosomen während der Mitose an entgegengesetzte Enden der Zelle bewegt und Organellen, das sind von Membranen umschlossene Kompartimente, entlang molekularer Schienen transportiert werden. Molekulare Motoren sind Proteine, deren Hauptaufgabe es ist, andere Moleküle zu bewegen. Dazu wandeln sie die bei der ATP-Hydrolyse freiwerdende chemische Energie in mechanische Arbeit um. Die Motoren des Zellskeletts gehören zu den drei Superfamilien Myosin, Kinesin und Dynein. Ihre Schienen sind Filamente des Zellskeletts, Actin und die Microtubuli.
In dieser Arbeit werden stochastische Modelle untersucht, welche dazu dienen, die Fortbewegung dieser linearen molekularen Motoren zu beschreiben. Die Skala, auf der wir die Bewegung betrachten, reicht von einzelnen Schritten eines Motorproteins bis in den Bereich der gerichteten Bewegung entlang eines Filaments. Ein Einzelschritt überbrückt je nach Protein etwa 10 nm und wird in ungefähr 10 ms zurückgelegt. Unsere Modelle umfassen M Zustände oder Konformationen, die der Motor annehmen kann, während er sich entlang einer eindimensionalen Schiene bewegt. An K Orten dieser Schiene sind Übergänge zwischen den Zuständen möglich. Die Geschwindigkeit des Proteins lässt sich in Abhängigkeit von den vertikalen Übergangsraten zwischen den einzelnen Zuständen analytisch bestimmen. Wir berechnen diese Geschwindigkeit für Systeme mit bis zu vier Zuständen und Orten und können weiterhin eine Reihe von Regeln ableiten, die uns einschätzen helfen, wie sich ein beliebiges vorgegebenes System verhalten wird.
Darüber hinaus betrachten wir entkoppelte Subsysteme, also einen oder mehrere Zustände, die keine Verbindung zum übrigen System haben. Mit einer bestimmten Wahrscheinlichkeit kann ein Motor einen Zyklus von Konformationen durchlaufen, mit einer anderen Wahrscheinlichkeit einen davon unabhängigen anderen.
Aktive Elemente werden in realen Transportvorgängen durch Motorproteine nicht auf die Übergänge zwischen den Zuständen beschränkt sein. In verzerrten Netzwerken oder ausgehend von der diskreten Mastergleichung des Systems können auch horizontale Raten spezifiziert werden und müssen weiterhin nicht mehr die Bedingungen der detaillierten Balance erfüllen. Damit ergeben sich eindeutige, komplette Pfade durch das jeweilige Netzwerk und Regeln für die Abhängigkeit des Gesamtstroms von allen Raten des Systems. Außerdem betrachten wir die zeitliche Entwicklung für vorgegebene Anfangsverteilungen.
Bei Enzymreaktionen gibt es die Idee des Hauptpfades, dem diese bevorzugt folgen. Wir bestimmen optimale Pfade und den maximalen Fluss durch vorgegebene Netzwerke.
Um darüber hinaus die Geschwindigkeit des Motors in Abhängigkeit von seinem Treibstoff ATP angeben zu können, betrachten wir mögliche Reaktionskinetiken, die den Zusammenhang zwischen den unbalancierten Übergangsraten und der ATP-Konzentration bestimmen. Je nach Typ der Reaktionskinetik und Anzahl unbalancierter Raten ergeben sich qualitativ unterschiedliche Verläufe der Geschwindigkeitskurven in Abhängigkeit von der ATP-Konzentration.
Die molekularen Wechselwirkungspotentiale, die der Motor entlang seiner Schiene erfährt, sind unbekannt.Wir vergleichen unterschiedliche einfache Potentiale und die Auswirkungen auf die Transportkoeffizienten, die sich durch die Lokalisation der vertikalen Übergänge im Netzwerkmodell im Vergleich zu anderen Ansätzen ergeben.
Transport processes in and of cells are of major importance for the survival of the organism. Muscles have to be able to contract, chromosomes have to be moved to opposing ends of the cell during mitosis, and organelles, which are compartments enclosed by membranes, have to be transported along molecular tracks.
Molecular motors are proteins whose main task is moving other molecules.For that purpose they transform the chemical energy released in the hydrolysis of ATP into mechanical work. The motors of the cytoskeleton belong to the three super families myosin, kinesin and dynein. Their tracks are filaments of the cytoskeleton, namely actin and the microtubuli.
Here, we examine stochastic models which are used for describing the movements of these linear molecular motors. The scale of the movements comprises the regime of single steps of a motor protein up to the directed walk along a filament. A single step bridges around 10 nm, depending on the protein, and takes about 10 ms, if there is enough ATP available. Our models comprise M states or conformations the motor can attain during its movement along a one-dimensional track. At K locations along the track transitions between the states are possible. The velocity of the protein depending on the transition rates between the single states can be determined analytically. We calculate this velocity for systems of up to four states and locations and are able to derive a number of rules which are helpful in estimating the behaviour of an arbitrary given system.
Beyond that we have a look at decoupled subsystems, i.e., one or a couple of states which have no connection to the remaining system. With a certain probability a motor undergoes a cycle of conformational changes, with another probability an independent other cycle.
Active elements in real transport processes by molecular motors will not be limited to the transitions between the states. In distorted networks or starting from the discrete Master equation of the system, it is possible to specify horizontal rates, too, which furthermore no longer have to fulfill the conditions of detailed balance. Doing so, we obtain unique, complete paths through the respective network and rules for the dependence of the total current on all the rates of the system. Besides, we view the time evolutions for given initial distributions.
In enzymatic reactions there is the idea of a main pathway these reactions follow preferably. We determine optimal paths and the maximal flow for given networks.
In order to specify the dependence of the motor's velocity on its fuel ATP, we have a look at possible reaction kinetics determining the connection between unbalanced transitions rates and ATP-concentration. Depending on the type of reaction kinetics and the number of unbalanced rates, we obtain qualitatively different curves connecting the velocity to the ATP-concentration.
The molecular interaction potentials the motor experiences on its way along its track are unknown. We compare different simple potentials and the effects the localization of the vertical rates in the network model has on the transport coefficients in comparison to other models.
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Vaukins, Simon. "The Isle of Man trophy motor-cycle races 1907 to the 1960s : Politics, economics and national identity." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527175.
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Winkel, Geellis. "IS-implementation : a tri-motors theory of organizational change : case study of how an IT-enabled process of organizational change because of the presence of a teleological, life-cycle, and dialectical motor unfolds within a Dutch government organization." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/5203.
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The reason for the study is that IT-enabled organizational change processes such as information system implementations have high costs and disappointing results. Studies to identify causes of the mentioned failures are mainly based on a variance approach. This study applies another approach which is not yet performed in this field of research and affects several themes. Based on a process approach data is compared with ideal-process theories to identify the generative mechanisms causing the unfolding of the process. Thus, the study identifies a recipe and not the ingredients.
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Barbosa, Cleiton Rubens Formiga. "Desempenho de um motor ciclo Otto com injeção direta de gás natural." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-05042005-104859/.
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Um motor ciclo Otto funcionando com injeção direta de gás natural, durante o curso de admissão, foi submetido a ensaios de plena carga em um dinamômetro corrente de Foucaut. Os resultados obtidos revelam um aumento de eficiência volumétrica do motor com injeção direta de GNC em relação à injeção indireta de GNC realizada no coletor de admissão, a montante da borboleta do acelerador. Na adaptação para operação com injeção direta de gás natural, as características técnicas do motor não foram alteradas. Um conjunto de injeção direta de gás natural, com gerenciamento eletrônico, foi inserido no cabeçote do motor de testes. Mantendo-se a pressão da linha de alimentação de gás natural constante, através de uma válvula redutora, a quantidade de combustível injetada no cilindro foi ajustada variando-se o tempo de abertura da válvula elétrica injetora de combustível. Dados de desempenho do motor são comparados, destacando-se os fatores que contribuem para este aumento relativo de eficiência volumétrica. Discute-se ainda, modificações a serem implementadas no motor visando maximizar sua potência com injeção direta de gás naturalOtto cycle engine direct injection natural gas, during the inlet stroke, submitted to runs with full power in a Foucaut dynamometer. The results obtained show a increase in the volumetric efficiency of the engine with natural gas direct injection when compared which natural gas injection apllied in the inlet manifold, upstream of the throttle butterfly. ln the conversion to natural gas direct injection, the technical characteristics of the were not changed. A kit for natural gas direct injection, with eletronic managment, was located on the cylinder head of the test engine. Maintaining the pressure constant in the natural gas fuel line, using a reduction valve. The mass of fuel injected into the cylinder was regulated, varying the opening time of the solenoid valve fuel injector. Engine performance data is compared, emphasizing the factors that contribute to this increase in relative volumetric efficiency. Modifications to be made to maximize the power of the engine with natural gas direct injection
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Novotný, Pavel. "Zážehový motor s Millerovým cyklem optimalizace provozu turbodmychadla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449786.
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The diploma thesis deals with the calculation of thermodynamic parameters of a turbocharged petrol engine with Miller cycle. A drive unit from Volkswagen, the EA211EVO model line, was chosen as the engine. The engine has a displacement of 1498 cm3 and engine power reaches 110kW at 5000 to 6000 RPM. In this work, a basic description of the thermodynamics of cycles of spark ignition engines is performed, then the problem of turbocharging and methods of its control are presented. The following are the created engine models in GTSuite environment in variants with WasteGate and Variable Turbine Geometry. Finally, operation optimizations with various valve timing changes are presented. The individual variants are the compared.
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Cruz, Vinicius Guimarães da. "Desenvolvimento experimental de um motor stirling tipo gama." Universidade Federal da Paraíba, 2012. http://tede.biblioteca.ufpb.br:8080/handle/tede/5341.
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The current paper develops an experimental Stirling engine Gama type. Different settings of this type of engine are presented (alpha, beta and gamma), along with the Stirling Cycle Definition and the mathematical modeling for each setting. It´s been Proceed a mathematical analysis based on the Stirling Theory, which is the method based upon the isothermical compression and expansion of an ideal gas, put to analysis by a computer software, determining the dependency between the engine s construction and functioning parameters. Bibliography used takes over the main Stirling engine settings and various working conditions, fed by a numerous types of fuels. The experimental part of the paper is assembling of a Stirling engine gamma type containing no regenerator, therefore, having the air as its working fluid, using electrical resistances as heat source, also a water jet at ambiance temperature to cool down the compression and heat exchanger. Engine tests were performed at atmospheric pressure, temperatures from 100 to 600 °C, 100 to 400 rpm rotations. The results are presented in graphics and are questioned.
O presente trabalho consiste no desenvolvimento experimental de um motor Stirling tipo gama. São apresentadas inicialmente as diferentes configurações deste tipo de motor (alfa, gama e beta), a definição do ciclo de Stirling e a modelagem matemática para cada configuração. Uma análise matemática é feita através da teoria de Schmidt, que é um método baseado na compressão e expansão isotérmica de um gás ideal, implementada em programa computacional permitindo determinar a dependência entre os parâmetros construtivos e de funcionamento do motor. A revisão bibliográfica contempla as principais configurações de motores Stirling e várias condições de funcionamento, alimentados por diversos tipos de combustíveis. A parte experimental do trabalho é a montagem de um protótipo de motor Stirling tipo gama sem regenerador tendo o ar como fluido de trabalho, utilizando resistências elétricas como fonte de calor e um fluxo de água a temperatura ambiente para o resfriamento do trocador de calor de compressão. Os testes do motor serão realizados a pressão atmosférica, para temperaturas de 100 a 600 °C e rotações de 100 a 400 rpm, os resultados são apresentados em gráficos e discutidos.
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Blanco, Cavero Diego. "Assessment and optimization of the indicated cycle with a 0D thermodynamic model." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/115934.
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[ES] Las amenazas a las que se enfrentan los motores de combustión interna, tales como emisiones contaminantes, agotamiento del petróleo o el auge de otros tipos de motores (vehículo eléctrico), vinculan el futuro de los vehículos propulsados por este tipo de motor a la mejora del mismo en cuanto a consumo de combustible y a emisiones contaminantes se refiere. Adicionalmente, la alta exigencia de la normativa actual y venidera está forzando a las empresas de automoción a centrarse en el desarrollo de estrategias innovadoras dirigidas a aumentar el rendimiento del motor con baja repercusión en emisiones contaminantes. Un primer paso para atajar esta problemática es centrarse en los procesos que ocurren en la cámara de combustión, que es la base del motor.
Teniendo en cuenta este escenario, el objetivo principal del presente trabajo es evaluar y optimizar el ciclo indicado de un motor de combustión interna por medio de una herramienta termodinámica 0D. El acoplamiento de esta herramienta, previamente desarrollada en el grupo de trabajo, con un modelo de emisiones de \NOx{} y una herramienta de optimización, permite la evaluación del impacto sobre el rendimiento indicado de varios límites operacionales y procesos reales que tienen lugar en la cámara de combustión.
En primer lugar, se ha evaluado el rendimiento indicado de diferentes ciclos ideales en los motores estudiados en el trabajo. Debido a que la diferencia entre ciclos ideales y reales es resultado de la existencia de varias imperfecciones, se ha realizado un estudio de sensibilidad de dichas imperfecciones para determinar cuáles son las que tienen mayor impacto sobre el rendimiento indicado. A continuación, se han buscado los ciclos teóricos óptimos, en este caso ya teniendo en cuenta los principales fenómenos que ocurren en el cilindro, para obtener la ley de combustión que maximiza el rendimiento indicado a la vez que cumple con diferentes restricciones mecánicas y límites de emisiones. En este análisis se concluye que la velocidad de combustión es el parámetro más importante a tener en cuenta.
Con el fin de evaluar algunas técnicas experimentales comúnmente usadas para aumentar la velocidad de combustión, parámetro clave como se ha comentado, se han utilizado diferentes enfoques tales como balances globales de energía, división de pérdidas y diseños de experimentos. Las conclusiones extraídas de dichos análisis han sido usadas para optimizar experimentalmente la ley de combustión. La comparación entre esta optimización experimental y la teórica proporciona el impacto en el rendimiento indicado que supone la limitación en la velocidad de combustión impuesta por el motor analizado. Esta metodología actúa como una herramienta de análisis comparativo entre diferentes arquitecturas del motor, estableciendo el techo de eficiencia bajo las condiciones de operación consideradas, y con ello la ganancia máxima alcanzable por un hipotético motor perfecto.[CAT] Les amenaces a què s'enfronten els motors de combustió interna, com ara emissions contaminants, esgotament del petroli o motors alternatius (vehicle elèctric), vinculen el futur dels vehicles propulsats per aquest tipus de motor a la millora del mateix quant a consum de combustible i a emissions contaminants es refereix. Addicionalment, l'alta exigència de la normativa actual i venidora està forçant a les empreses d'automoció a centrar-se en el desenrotllament d'estratègies innovadores dirigides a augmentar el rendiment del motor amb baixa repercussió en emissions contaminants. Un primer pas per a atallar esta problemàtica és centrar-se en els processos que ocorren en la cambra de combustió, que és la base del motor. Tenint en compte aquest escenari, l'objectiu principal del present treball és avaluar i optimitzar el cicle indicat d'un motor de combustió interna per mitjà d'una ferramenta termodinàmica 0D. L'adaptament d'esta ferramenta, prèviament desenrotllada en el grup de treball, amb un model d'emissions de \NOx{} i una ferramenta d'optimització, permet l'avaluació de l'impacte sobre el rendiment indicat d'uns quants límits operacionals i processos reals que tenen lloc en la cambra de combustió. En primer lloc, s'ha avaluat el rendiment indicat de diferents cicles ideals en els motors estudiats en el treball. Pel fet que la diferència entre cicles ideals i reals és resultat de l'existència de diverses imperfeccions, s'ha realitzat un estudi de sensibilitat de les dites imperfeccions per a determinar quines són les que tenen major impacte sobre el rendiment indicat. A continuació, s'han buscat els cicles teòrics òptims, en aquest cas ja tenint en compte els principals fenòmens que ocorren en el cilindre, per a obtindre la llei de combustió que maximitza el rendiment indicat al mateix temps que compleix amb diferents restriccions mecàniques i límits d'emissions. En aquest anàlisi es conclou que la velocitat de combustió és el paràmetre més important a tindre en compte. A fi d'avaluar algunes tècniques experimentals comunament usades per a augmentar la velocitat de combustió, paràmetre clau com s'ha comentat, s'han utilitzat diferents enfocaments com ara balanços globals d'energia, divisió de pèrdues i dissenys d'experiments. Les conclusions extretes d'aquest anàlisi han sigut usades per a optimitzar experimentalment la llei de combustió. La comparació entre esta optimització experimental i la teòrica proporciona l'impacte en el rendiment indicat que suposa la limitació en la velocitat de combustió imposada pel motor analitzat. Esta metodologia actua com una ferramenta d'anàlisi comparativa entre diferents arquitectures del motor, establint el sostre d'eficiència davall les condicions d'operació considerades, i amb això el guany màxim abastable per un hipotètic motor perfecte.
[EN] Issues affecting internal combustion engines, such as pollutant emissions, oil depletion and the raising of alternative powertrains (full electric vehicle), link the future of vehicles powered by this type of powertrain to its improvement in terms of fuel consumption and pollutant emissions. Additionally, the high stringency of the current and upcoming legislation is forcing automotive manufacturers to focus on developing innovative engine strategies aimed to increase the efficiency with low penalty in emissions. A first step to tackle this issue is to focus on the processes occurring in the combustion chamber, which is the core of the engine. Taking into account this scenario, the main objective of the present work is to assess and optimize the indicated cycle of an internal combustion engine based on a zero-dimensional thermodynamic tool. The coupling of this tool, previously developed in the work group, with a \NOx{} emissions model and an optimization tool allows evaluating the impact on gross indicated efficiency of several operational limits and real processes taking place in the combustion chamber. Thus, the first step was the assessment of the indicated efficiency of some ideal cycles in the engines studied in the work. Since the difference between ideal and real cycles is due to the existence of some imperfections, a sensitivity study of these imperfections is carried out to determine the ones with the highest impact on gross indicated efficiency. Later on, the optimum theoretical cycles have been searched for, now taking into account the main phenomena occurring in the cylinder, to get the combustion profile that maximizes the indicated efficiency while keeping some mechanical restrictions and emission limits. In this analysis, the combustion velocity raised as the most important parameter to take into account. In order to assess some experimental techniques commonly used to enhance the combustion velocity, key parameter as commented, different approaches such as Global Energy Balance, split of losses and the use of design of experiments have been conducted. The conclusions extracted from these analysis have been used to optimize experimentally the combustion law. The comparison between this experimental optimization and the theoretical one provides the impact on gross indicated efficiency of the combustion velocity limitation imposed by the engine hardware. This methodology acts as a benchmarking tool between different hardware architectures, setting the efficiency ceiling of the considered operating point, and thus the maximum gain achievable by implementing an hypothetical perfect hardware.
Blanco Cavero, D. (2018). Assessment and optimization of the indicated cycle with a 0D thermodynamic model [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/115934
TESIS
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Cattuzzo, Maria Teresa. "O ciclo instabilidade-estabilidade-instabilidade no processo adaptativo em aprendizagem motora." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/39/39132/tde-24042008-064211/.
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O objetivo foi investigar a aquisição de habilidades motoras, no modelo do Processo Adaptativo, testando dois ciclos de Instabilidade-Estabilidade-Instabilidade (I-E-I). Duzentos e quarenta homens adultos jovens participaram de dois experimentos realizando uma tarefa seriada de rastreamento. As variáveis dependentes foram as respostas omissas, erradas, corretas e antecipatórias. O Experimento 1 testou o efeito dos Intervalos Inter-Estímulos (IIEs) em uma fase de aquisição num delineamento com seis grupos (300, 400, 500, 600, 700 e 800 ms de IIE); os testes estatísticos indicaram efeito de interação de grupos e blocos em todas as respostas. Com base nesses resultados foi elaborado o experimento principal com a mesma tarefa, num delineamento de três fases (Estabilização, Adaptação I e II) com o intuito de analisar o efeito dos ciclos I-E-I e dos IIEs no desempenho. Foram testados seis grupos nos quais os IIEs eram modificados de uma fase para outra. Os testes estatísticos mostraram efeito de interação entre grupos e blocos para os quatro tipos de resposta. Em seu conjunto, os resultados indicam que a aquisição de habilidades se dá mediante sucessivos ciclos de estabilização-adaptação, que leva ao aumento de complexidade; houve efeito do nível de estabilização alcançado no primeiro ciclo para o segundo ciclo de I-E-I e da magnitude da perturbação; a redundância inicial na estrutura teve efeito no desempenho em respostas funcionais ao longo dos ciclosThe aim of this study was to investigate the acquisition of motor learning as proposed by Adaptive Process model of motor learning by testing two Instability- Stability-Instability cycles (IN-ST-IN). Two hundred and forty young adult men participated in the two experiments in which a serial tracking task was used. The dependent variables were anticipatory, correct, incorrect and omission responses. The first experiment tested the effect of the Inter-Stimuli-Intervals (ISI) in an acquisition phase with a design comprised by six groups (300, 400, 500, 600, 700 e 800 ms of ISI); the MANOVA statistics (6 Groups X 3 Blocks) indicated interaction effect in all responses. Based on these results the main experiment was set up with a design of three phases (Stabilization, Adaptation I and II) with the aim to analyze the effect of the IN-ST-IN cycles and the ISIs on four responses. Six groups were tested in which the ISI were modified in each phase. The MANOVA statistics (6 Groups X 5 Blocks) indicated interaction effect in all responses. In sum, the results indicated that the acquisition process of motor skills takes place in the course of successive stabilization-adaptation cycles that lead to the increase to system\'s complexity; there was observed effect of the first cycle stabilization level on the second cycle; the early redundancy in the structure had effect on the functional responses performance, throughout the cycles
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Malleichervu, Govind N. "PROPORTIONAL FEEDBACK CONTROL OF DUTY CYCLE FOR DC HYBRID ACTIVE POWER FILTER." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/555.
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This thesis deals with the design and implementation of a feedback control scheme for a DC Hybrid Active Power Filter used to filter harmonics from a Switched Reluctance Motor (SRM) Drive load. Power electronic systems are non-linear & dynamic [1,3,5]. Power electronic systems employ switching circuits to maximize their efficiency at the penalty that switching circuits generate electrical noise called ripple current and voltage or conducted electromagnetic interference (EMI). The ripple current drawn by the power electronic systems needs to be attenuated to an acceptable level. Filters attenuate this to an acceptable level. Traditionally filters with passive inductors and capacitors are used. Active filters contain switching elements in addition to passive inductors and capacitors which reduce overall size of passive components used.
Two control approaches, full-state state space, and plain proportional feedback, are evaluated for this filter. Circuit models are simulated in SPICE and mathematical models are simulated in Matlab/Simulink for evaluating these control approaches. Proportional feedback control was chosen for implementation and the reason for this is provided in the thesis. The active filter was tested with chosen feedback control and experimental results were compared with simulation results. Inferences and scope for further work are finally presented.
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Houdyschell, David. "A diesel two-stroke linear engine." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1312.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains ix, 64 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 42-43).
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Ferraz, Fagner Barbosa. "Análise de desempenho de um motor diesel turboalimentado ottolizado para gás natural." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5384.
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Previous issue date: 2014-06-30Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
A large number of national companies has been using diesel gensets as an alternative to the electricity supplied by the local utility. Therefore, generators are used as an emergency power system or during peak hours. Peak hour in Brazil is between 5 to 10 p. m. As we know diesel engines contribute to the large increase in environmental pollution, since the diesel exhaust may contain fine particles associated with negative health effect, toxic air contaminants, as NOx and SOx. On the other hand, Natural gas is considered as a suitable choice rather than the use of diesel, because it possesses high calorific power, clean burning, and proper octane level for Otto cycle engine. The present work deals with the performance analysis of a Perkins engine turbocharged, diesel, model 1104C-44TA, converted into an Otto cycle engine to run on natural gas, also identifying the limiting factors of power in these types of engines. Giving the importance of the compression rate on the Diesel to Otto cycle conversion, the evaluation of the Perkins processed engine happened under the influence of three different rates: 7.6:1; 8.7:1 and 12.3:1. For each compressed rate, and stoichiometric mixture, the task was to choose the spark advance to guarantee best performances to the engine. All tests were performed with a hydraulic dynamometer. The results showed that, the best combination of those parameters are not sufficient to ensure the highest performance of a diesel converted engine. There was a consubstantial rise in temperature of the exhaust gases and on the turbine walls, due to the increase in the exhaust gases volume, compared to that of the burnt gases withdrawn from the original engine, impairing the efficiency and lifespan of the engine components. It was found, by energetic analysis, the compression ratio of 8.7:1, was the most efficient, among the other two, assuring the engine its best performance. As expected, at the compression rate of 7.6:1 the exhaust gases presented the highest temperatures. At compression ratio of 12.3:1 the gas emissions of the converted engine delivered highest NOx level and the lowest level of unburned hydrocarbons at the exhaust. Keywords: Diesel Turbocharged Engine. Diesel to Otto Cycle Conversion Process. Natural Gas. Performance. Energy Balance
Um grande número de empresas nacionais faz uso de grupos geradores a diesel como opção à eletricidade fornecida pela concessionária local. O emprego de grupos geradores é comum durante as horas de pico, que no Brasil, ocorrem entre as 17 e 22 h. Tais aparatos, juntamente com os motores veiculares a diesel têm contribuído para o grande aumento da poluição ambiental, uma vez que a queima deste combustível se faz com grande emissão de particulados, de NOx e de SOx. O gás natural é considerado uma alternativa ao uso do diesel por possuir um alto poder calorífico, queima limpa, e adequada octanagem para o ciclo Otto. O presente trabalho trata da análise de desempenho de um motor Perkins turboalimentado, a diesel, modelo 1104C-44TA, convertido para funcionar apenas com gás natural, identificando ainda, os fatores limitadores de potência nestes tipos de motores. Considerando a importância da taxa de compressão no processo de ottolização, o motor convertido foi avaliado sob a influência de três diferentes taxas: 7,6:1; 8,7:1 e 12,3:1. Para tanto, foram selecionados avanços de ignição que ao interagir com a mistura próxima da estequiométrica garantisse ao funcionamento do motor as melhores condições de desempenho, para cada taxa de compressão escolhida. Os ensaios foram feitos com o auxílio de um dinamômetro hidráulico e os resultados obtidos evidenciaram que, na prática, tais parâmetros não são suficientes para se assegurar os melhores desempenhos em um motor diesel ottolizado. Foi observado um aumento consubstancial na temperatura dos gases de exaustão e na turbina, em virtude da ampliação do volume dos gases de escapamento com relação àquele observado no motor original, com prejuízos para a eficiência e a própria vida útil do motor. Verificou-se, através das análises energéticas, que a taxa de compressão de 8,7:1 permitiu ao motor seu melhor desempenho, com relação à outras experimentadas. Como esperado, o motor operando na taxa de 7,6:1 produziu as mais elevadas temperaturas dos gases de exaustão. Com respeito às emissões gasosas, o motor convertido com taxa de compressão de 12,3:1 emitiu o maior nível de NOx e o menor nível de hidrocarbonetos não queimados
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Castellanelli, Márcio. "Desempenho de motor Ciclo diesel em bancada dinamométrica utilizando Biodiesel etílico de soja." Universidade Estadual do Oeste do Parana, 2006. http://tede.unioeste.br:8080/tede/handle/tede/393.
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Previous issue date: 2006-07-27Ahead of the forecast of scarcity of the oil, the ethyl ester (biodiesel) if has presented as an excellent alternative fuel option for engines cycle diesel. The characteristics of biodiesel are similar of diesel in terms of viscosity and the calorific power, being able to be used without adaptations in the engines. For accomplishment of this work, a motor cycle was used diesel, of direct injection with four cylinders, without adaptations. The engine was connected to a dynamometer and systems of acquisition of data auxiliary for the register of the necessary data. The performances of torque, power and brake specific fuel consumption for the following mixtures had been evaluated: B2, B5, B10, B20, B50, B75 and B100. The best registered performance was given with the B20 mixture.
Diante da previsão de escassez do petróleo, o éster etílico (biodiesel) tem se apresentado como uma excelente opção de combustível alternativo para motores ciclo diesel. As características do biodiesel são semelhantes as do diesel em termos de viscosidade e poder calorífico, podendo ser utilizado sem adaptações nos motores. Para realização deste trabalho, utilizou-se um motor ciclo diesel, de injeção direta com quatro cilindros, sem adaptações. O motor foi acoplado a um dinamômetro e sistemas de aquisição de dados auxiliares para o registro dos dados necessários. Avaliaram-se os desempenhos de torque, potência e consumo específico de combustível para as seguintes misturas: B2, B5, B10, B20, B50, B75 e B100. O melhor desempenho registrado deu-se com a mistura B20.
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Herwald, Marc A. "Control Design and Analysis of an Advanced Induction Motor Electric Vehicle Drive." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/32934.
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This thesis is about the development and performance enhancement of an induction motor electric vehicle drive system. The fundamental operation of the induction motor drive hardware and control software are introduced, and the different modulation techniques tested are described. A software simulation package is developed to assist in the control design and analysis of the drive system. Next, to establish the efficiency gains obtained by using space vector modulation in the improved drive system, an inverter with hysteresis current control is compared to the same inverter with space vector modulation in steady state and on separate driving profiles. A method for determining induction motor harmonic losses is introduced and is based on obtaining the phase current harmonics from sampled induction motor stator phase currents obtained. Using a semi-empirical loss model, the induction motor losses are compared between different pulse width modulation control strategies throughout the torque versus speed operating region. Next, several issues related to the robustness of the control design are addressed. To obtain good performance in the actual vehicle, a new method for driveline resonance compensation is developed and proven to work well through simulation and experiment. Lastly, this thesis discusses the development of a new method to compensate for the gain and phase error obtained in the feedback of the d-axis and q-axis stator flux linkages. Improved accuracy of the measured stator flux linkages will be shown to improve the field oriented controller by obtaining a more accurate measurement of the feedback electromagnetic torque.Master of Science
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Barragan, Neto Valter. "Simulação computacional em camisas de motor construídas em liga de alumínio silício." Universidade Presbiteriana Mackenzie, 2011. http://tede.mackenzie.br/jspui/handle/tede/1321.
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Previous issue date: 2011-09-27General Motors do Brasil
Automotive cylinder liners are mechanical components with the function of internal coating of the cylinder automotive engines. The liners have been made of cast iron, which meets the necessary requirements. The replacement of parts made of steel/ cast iron in aluminum alloys has been made with advantages not only in reducing weight as well as fuel consumption and emission of pollutants. This work has an objective to study the possibility to apply the cylinder liners built in aluminum and silicon alloy on engines with computer aided engineering help. The finite element method consists to generate a mathematical model with computational assistance, of geometry, representing several elements that have in common the node connection, forming the finite element, defined as a mesh. For each node the partial differential equations are solved by numerical methods. This study was aided by finite element software Hyperworks, where the mesh was generated and was exported to Abaqus where were performed the processing of input data. The starting point for the simulation of aluminum liners used in internal combustion engines was to define the format of the mesh for the engine block with less refinement, was chosen a mesh with tetrahedron elements of 4 nodes of with size ranging between 1 mm and 12 mm of edge element. The liners was designed with hexahedron elements of six nodes, which by definition are more consistent and have more accurate answers to the elements tetrahedrons and with a larger refinement, about 1 mm, both elements are first order elements with no nodes on edge s midpoint . In function of the process of manufacturing the liners to be cast by centrifugation, layers of elements were created to meet the variation in the amount of the silicon liner, which in turn affects the physical properties of the liner along the thickness of the wall. With this model it was possible to show the viability of applying these liners in engine blocks of cast iron. The analysis has shown that a prototype could be build in order to test the cylinder liners application and also test the wear of the cylinder liner.
Camisas de cilindro automotivo são componentes mecânicos com a função de revestir internamente os cilindros dos motores automotivos. As camisas de cilindros têm sido feitas de ferro fundido, que atende os requisitos necessários de desgaste e rigidez. A substituição de partes feitas em aço e ferro fundido por ligas de alumínio em veículos têm vantagens não só na diminuição de peso como também no consumo de combustível e emissão de poluentes. Este trabalho teve por objetivo estudar a viabilidade da aplicação de camisas constituídas em liga de alumínio e silício em motores com o auxilio de engenharia assistida por computador. O método de modelagem em elementos finitos consiste em gerar um modelo matemático auxiliado por computador, da geometria, constituída por vários elementos que têm em comum nós de ligação formando os elementos finitos, assim definidos por malha. Para cada um dos nós são resolvidas as equações diferenciais parciais por métodos numéricos. O estudo em elementos finitos foi auxiliado pelos softwares Hyperworks, onde foi gerada a malha e exportada para o Abaqus onde foi realizado o processamento dos dados de entrada. O ponto de partida para a simulação das camisas de alumínio aplicadas em motores de combustão interna foi definir a formato da malha para o bloco com um menor refinamento, foi então escolhida uma malha com elementos tetraédricos de quatro nós de tamanho variando entre 1 mm e 12 mm de aresta de elemento. A camisa foi elaborada com elementos hexaédricos de seis nós, que por definição são mais fiéis e possuem respostas mais precisas que os elementos tetraédricos, e com um refinamento maior, cerca de 1 mm, ambos de primeira ordem sem nós intermediários nas arestas. Em função do processo de fabricação da camisa ser a fundição por centrifugação, camadas de elementos foram criadas a fim de satisfazer a variação da quantidade de silício da camisa, que por sua vez afeta as propriedades físicas da camisa ao longo da espessura da parede. Com este modelo foi possível mostrar a viabilidade da aplicação dessas camisas em motores com blocos de ferro fundido. As análises mostraram que um protótipo poderá ser construído para testar a aplicação destas camisas e testá-las quanto ao desgaste.
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Shaw, Kendrick Matthew. "Dynamical Architectures for Controlling Feeding in Aplysia californica." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1382998904.
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Estrada, Javier Solis. "DESEMPENHO E EMISSÕES DE UM MOTOR DE TRATOR AGRÍCOLA OPERANDO COM MISTURAS DE ÓLEO DIESEL E ETANOL." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/7597.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThe growing demand of energy in the world, the decrease of petroleum reserves and the current problems of environmental contamination, increase the interest in renewable energy study for internal combustion engines, to replace partially or completely to petroleum based fuels. In Brazil, among the alternatives fuels, stands out the use of sugarcane ethanol, seen that it is from renewable sources and has high oxygen content, which is favorable to reduce pollutant gases emissions of engine. The blend of ethanol and diesel (ED) has received in recent years and in different countries, more attention for use in diesel engines. However, there are difficulties to partially replace diesel use. The main disadvantages are the differences in their physical-chemical properties. A percentage up to 15% of ethanol is used in diesel engines without making mechanical changes. In this way, the objective of this study was to evaluate the performance and emissions of a diesel engine in an agricultural tractor, using blends of diesel and hydrated ethanol. Were used as fuel, Diesel (B5) and mixture with 3% (ED3), 6% (ED6), 9% (ED9), 12% (ED12) and 15% (ED15) of hydrous ethanol. Performance parameters evaluated were the power, torque and specific fuel consumption. Were also evaluated emissions of CO2, NOx e O2, and the opacity of the gases through the k value. Both, engine performance and emissions experiment were analyzed in a completely randomized with bifactorial design. The results indicate that as the percentage of ethanol increased, the average values of torque and engine power decreased. Using the B5 and the ED3, these variables did not differ statistically, in addition, with the ED3 was obtained the lower specific fuel consumption. Using ED12, the engine performance has reduced power and torque in 2.97% e 2.95%, respectively, compared with B5, while their fuel consumption had no statistical difference. The greater opacity and gas emissions were archive with ED3, while the lower emission occurred when the engine operated with ED12 and ED15. With these fuels, the reduction of opacity, CO2 and NOX, in relation to B5, was 22.22 24.44%, 5.20 5.60% e 6.65 - 10.48%, respectively. It can be considerate that operating with ED12, pollutant emissions are reduced significantly without a significant loss in engine performance.
A crescente demanda mundial de energia, a diminuição das reservas do petróleo e os atuais problemas de poluição ambiental, incrementam o interesse no estudo de fontes renováveis de energia para os motores de combustão interna, visando substituir, de forma parcial ou total, os combustíveis derivados do petróleo. No Brasil, entre os combustíveis alternativos, se destaca o uso do etanol de cana-de-açúcar, visto que é de origem renovável e possui um alto conteúdo de oxigênio, o qual pode favorecer a redução das emissões de gases poluentes do motor. A mistura etanol- Diesel (ED) vem recebendo, nos últimos anos, e em diferentes países, maior atenção para ser utilizado em motores ciclo Diesel. No entanto, existem dificuldades para sua utilização visando substituir parcialmente o óleo Diesel. Os principais inconvenientes são as diferenças nas suas propriedades físico-químicas. Em porcentagens de até 15%, o etanol pode ser utilizado em motores ciclo Diesel, sem realizar modificações mecânicas. Desta forma, o objetivo deste trabalho foi avaliar o desempenho e as emissões de um motor ciclo Diesel de um trator agrícola, utilizando misturas de óleo Diesel e etanol hidratado. Foram utilizados como combustíveis o óleo Diesel (B5) e sua mistura com 3% (ED3), 6% (ED6), 9% (ED9), 12% (ED12) e 15% (ED15) de etanol. Os parâmetros avaliados de desempenho foram: a potência, o torque e consumo específico de combustível. Foram também avaliadas as emissões de CO2, NOx, O2 e a opacidade dos gases, por meio do valor k. Ambos os experimentos de desempenho e emissões do motor foram analisados em um delineamento experimental inteiramente casualizado, em um esquema bi fatorial. Os resultados indicam que conforme aumentou a porcentagem de etanol, os valores médios de torque e potência do motor diminuíram. Utilizando o B5 e o ED3, estas variáveis não diferiram estatisticamente, além disso, com o ED3 foi obtido o menor consumo de combustível. Utilizando o ED12 o desempenho do motor teve reduções de potência e torque de 2,97% e 2,95%, respectivamente, em relação ao B5, enquanto que os consumos de combustível não tiveram diferença estatística. A maior opacidade e emissões de gases foram alcançadas com ED3, enquanto que as menores emissões ocorreram quando o motor operou com o ED12 e ED15. Com estes combustíveis, a redução da opacidade, CO2 e NOx, em relação ao B5 foi de 22,22 - 24,44%, 5,20 - 5,60% e 6,65 - 10,48%, respectivamente. Pode-se considerar que operando com o ED12, as emissões de poluentes são reduzidas significativamente sem uma perda considerável no desempenho do motor.
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Tavares, Gracilene Rodrigues. "Funcionalidade em pacientes ap?s acidente vascular encef?lico: rela??o com o sono e ritmo de atividade-repouso." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16685.
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Previous issue date: 2010-08-27Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
It is known that sleep plays an important role in the process of motor learning. Recent studies have shown that the presence of sleep between training a motor task and retention test promotes a learning task so than the presence of only awake between training and testing. These findings also have been reported in stroke patients, however, there are few studies that investigate the results of this relationship on the functionality itself in this population. The objective of this study was to evaluate the relationship between functionality and sleep in patients in the chronic stage of stroke. A cross-sectional observational study was conducted. The sample was composed of 30 stroke individuals in chronic phase, between 6 and 60 months after injury and aged between 55 and 75 years. The volunteers were initially evaluated for clinical data of disease and personal history, severity of stroke, through the National Institute of Health Stroke Scale, and mental status, the Mini-Mental State Examination. Sleep assessment tools were Pittsburgh Sleep Quality Index, the Questionnaire of Horne and Ostberg, Epworth Sleepiness Scale, the Berlin questionnaire and actigraphy, which measures were: real time of sleep, waking after sleep onset, percentage of waking after sleep onset, sleep efficiency, sleep latency, sleep fragmentation index, mean activity score. Other actigraphy measures were intraday variability, stability interdi?ria, a 5-hour period with minimum level of activity (L5) and 10-hour period with maximum activity (M10), obtained to evaluate the activity-rest rhythm. The Functional Independence Measure (FIM) and the Berg Balance Scale (BBS) were the instruments used to evaluate the functional status of participants. The Spearman correlation coefficient and comparison tests (Student's t and Mann-Whitney) were used to analyze the relationship of sleep assessment tools and rest-activity rhythm to measures of functional assessment. The SPSS 16.0 was used for analysis, adopting a significance level of 5%. The main results observed were a negative correlation between sleepiness and balance and a negative correlation between the level of activity (M10) and sleep fragmentation. No measurement of sleep or rhythm was associated with functional independence measure. These findings suggest that there may be an association between sleepiness and xii balance in patients in the chronic stage of stroke, and that obtaining a higher level of activity may be associated with a better sleep pattern and rhythm more stable and less fragmented. Future studies should evaluate the cause-effect relationship between these parameters
Sabe-se que o sono exerce um importante papel no processo de aprendizado motor. Estudos recentes demonstraram que a presen?a do sono entre o treino de uma tarefa motora e o teste de reten??o promove um aprendizado da tarefa de forma superior ? presen?a apenas de vig?lia entre treino e teste. Estes achados tamb?m t?m sido encontrados em pacientes que sofreram acidente vascular encef?lico (AVE), entretanto, faltam estudos que investiguem os resultados desta rela??o sobre a funcionalidade propriamente dita nesta popula??o. O objetivo desta pesquisa foi verificar a rela??o entre capacidade funcional e sono em pacientes em est?gio cr?nico de acidente vascular encef?lico. Foi realizado um estudo observacional anal?tico transversal. A amostra foi composta por 30 indiv?duos com seq?elas motoras de AVE em fase cr?nica, faixa et?ria entre 55 e 75 anos, apresentando tempo de seq?ela entre 6 e 60 meses. Os volunt?rios foram inicialmente avaliados quanto aos dados cl?nicos e antecedentes pessoais, severidade do AVE, atrav?s da escala internacional de AVE do National Institute of Health, e estado mental, pelo Mini-Exame do Estado Mental. Os instrumentos de avalia??o do sono foram o ?ndice de Qualidade do Sono de Pittsburgh, o question?rio de Horne e Ostberg, Escala de Sonol?ncia de Epworth (ESE), o question?rio de Berlim e a actimetria, cujas medidas utilizadas foram: tempo real de sono, tempo de vig?lia ap?s o in?cio do sono, porcentagem de tempo de vig?lia ap?s o in?cio do sono, efici?ncia do sono, lat?ncia para o sono, ?ndice de fragmenta??o do sono, m?dia do escore de atividade. Outras medidas da actimetria foram a variabilidade intradi?ria, estabilidade interdi?ria, per?odo de 5 horas com n?vel m?nimo de atividade (L5) e per?odo de 10 horas com n?vel m?ximo de atividade (M10), obtidas para avalia??o do ritmo de atividade-repouso. A Medida de Independ?ncia Funcional (MIF) e a Escala de Equil?brio de Berg (EEB) foram os instrumentos utilizados para avalia??o da condi??o funcional dos participantes. O coeficiente de correla??o de Spearman e testes comparativos (t de student e Mann-Witney) foram utilizados para an?lise da rela??o dos instrumentos de avalia??o do sono e do ritmo de atividade/repouso com as medidas de avalia??o funcional. O programa estat?stico SPSS 16.0 foi empregado para as an?lises, adotando-se n?vel de signific?ncia de 5%. Os principais resultados observados foram uma correla??o negativa entre sonol?ncia e equil?brio e uma correla??o negativa entre o n?vel de atividade (M10) e fragmenta??o do sono. Nenhuma medida do sono ou do ritmo foi associada com a medida de independ?ncia funcional. Estes achados sugerem que pode haver uma associa??o entre sonol?ncia e equil?brio em pacientes em est?gio cr?nico de AVE, e ainda que a obten??o de um maior n?vel de atividade pode estar associada a um melhor padr?o de sono e ritmo mais est?vel e menos fragmentado. Futuros estudos devem avaliar a rela??o de causa-efeito entre estes par?metros
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Alves, André Felipe Alves. "Influência do resfriamento da turbina no desempenho de um motor diesel turboalimentado ottolizado para gás natural." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8980.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Seeking to meet the electricity demand in Brazil, power plants, industries and businesses showed an increase in consumption of natural gas by 17.5% between 2013 and 2014 (RESENHA ENERGÉTICA BRASILEIRA, 2015). Most of these facilities use generators for electricity through natural gas. Such groups are formed generally by a Diesel engine coupled to an electric generator. The engines of these groups may be classified as aspirated or turbocharged. It is known, moreover, that the gaseous emissions generated by the Diesel engine, make replaced by clean fuels such as natural gas, an attractive alternative. Converstion of Diesel engines for the Otto cycle, may be an option for generating electricity from natural gas, mainly because it is a low cost compared to the price of gas gensets technology. However, in turbocharged engines converted to natural gas, are identified during operations, temperatures higher than those allowed in the turbine, limiting thus the possibility of reaching the rated power of these motors. The use, however, a heat exchanger gives rise to a Diesel engine converted to Otto cycle work without restriction in all its power domain. This paper examines the issues related to the choice of a heat exchanger, construction, installation and the results of its operation in a motor Perkins turbocharged converted to Otto cycle for natural gas. In performance tests, we used a hydraulic dynamometer, with a maximum of 500 hp capacity. All tests were performed with the rotation set at 1800 RPM, for all powers of labor, including the original maximum power that had diesel, stand-by time of 153 cv (112.4 kW). The maximum thermal efficieny of the engine was 39.1 % for 153 cv power. The NOx and CO levels, were, respectively, 348 ppm and 3.48 % when the engine is operated at power of 153 cv. The effectiveness of the introduced heat exchanger ranged between 33 and 33.7 %.
Buscando suprir a demanda de energia elétrica no Brasil, as termelétricas, indústrias e estabelecimentos comerciais apresentaram um aumento no consumo de gás natural de 17,5% entre 2013 e 2014 (RESENHA ENERGÉTICA BRASILEIRA, 2015). A maioria dessas instalações utilizam grupos geradores para obter energia elétrica. Tais grupos são formados, geralmente, por um motor Diesel acoplado a um gerador elétrico. Os motores desses grupos, podem ser classificados como aspirados ou turboalimentados. Sabe-se, por outro lado, que os níveis de emissões gasosas geradas pela combustão do diesel, torna sua substituição por combustíveis não poluentes, como o gás natural, uma alternativa atrativa. A conversão dos motores Diesel para o ciclo Otto (Ottolização), pode ser uma opção para a geração de energia elétrica a partir do gás natural, sobretudo, por ser uma tecnologia de baixo custo frente aos preços dos grupos geradores a gás. No entanto, nos motores turboalimentados convertidos para gás natural, são identificadas, durante suas operações, temperaturas superiores àquelas permitidas na turbina, limitando, desta forma, a possibilidade de se chegar às potências nominais desses motores. O uso, todavia, de um trocador de calor dá margem para que um motor Diesel ottolizado funcione, sem restrições, em todo seu domínio de potência. Este trabalho examina os aspectos relacionados à escolha de um trocador de calor, sua construção, instalação e os resultados de seu funcionamento em um motor Perkins turboalimentado Ottolizado para gás natural. Nos testes de desempenho, utilizou-se um dinamômetro hidráulico, com capacidade máxima de 500 cv. Todos os ensaios foram feitos com a rotação fixada em 1800 RPM, para todas as potências de trabalho, inclusive a potência máxima original que se tinha com diesel, em stand-by, de 153 cv (112,4 kW). O máximo rendimento térmico do motor foi de 39,1 % para a potência de 153 cv. Os níveis de NOx e de CO, ficaram, respectivamente, em 348 ppm e 3,48 % quando o motor operava na potência de 153 cv. A efetividade do trocador de calor introduzido variou de 33 a 33,7 %.
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Hugosson, Conny, Omer Kayani, and Mark Krieg. "Customer focused development of a variable bent-axis pump/motor for open circuit hydrostatic transmissions, e.g. in hydraulic hybrid drives." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200062.
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The paper presents the development methodology of a hydrostatic pump/motor for use in Parker Hannifin’s advanced series hydraulic hybrid transmissions for medium and heavy duty commercial vehicles. With Parker’s established bent-axis pump/motor technology for heavy duty mobile applications as a basis, it describes the main stages of further development and qualification for demanding automotive main drive transmissions. Parker’s APQP based, customer focused product development model was employed for this development which resulted in the variable bent-axis pump/motor C24 for open circuit hydrostatic transmissions. Positive customer results from a large fleet of in-service refuse collection trucks and parcel delivery vans with Parker advanced hydraulic hybrid drive systems using C24 pumps/motors serve as evidence of Parker’s product development model effectiveness.
High reliability, good fuel economy, increased productivity and long brake life of the vehicles can directly be traced back to the streamlined, front-loaded and iterative development model.
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Černý, Roman. "Výpočtová studie Millerova cyklu benzínového motoru s turbodmychadlem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318533.
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The scope of this thesis is the Miller engine cycle analysis and its practical application on a turbocharged spark ignited engine. Based on the sensitivity analysis of the limits affecting the ideal Miller cycle thermal efficiency a thermodynamic model of the engine with a prolonged expansion was set up in the GT-POWER software. The results of the analyses were used to evaluate the feasibility of the reference engine conversion for an operation with Miller cycle.
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Barros, Bruno Vinícius de menezes'. "Efeito da contrapressão e do resfriamento da turbina no desempenho de um motor diesel ottolizado para gás natural." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/8976.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The cost of the kWh at the peak hour in Brazil may be up to nine times higher than the one at normal hours. This fact has served as motivation for industries, shopping malls, hotels, and so on, to utilize electrical generators. These generator sets generally comprise Diesel engines. The problem is that the exhaust gases from these engines are very harmful to health. On the other hand, Natural Gas, thanks to its high calorific power and its low emissions, is considered a clean-burning alternative fuel. Therefore, the Diesel engines converted to Otto cycle may considerably reduce the environmental pollution. Such a conversion, however, may have in turbocharged engines backpressure effects that increase the temperature of the turbine, reducing the energy efficiency of the engine. The present study analyzes the result and consequences of the replacement of the original manifold by another with smoother curves, as well as the cooling effect on the engine performance of the turbine of a Perkins turbocharged model 1104C-44TAG2, converted to the Otto cycle. First, tests were made running the engine with its original manifold without any cooling, and then, having the turbine cooled with room air. After the replacement of the manifold, new teste were performed. Initially, without cooling the turbine or the manifold. Then, after the replacement of the manifold, other tests ventilating the turbine and the manifold were made. In each test, one has registered: the maximum operation power; temperature of the exhaust gases and the engine consumption in terms of the backpressure due to the manifold. All the tests were performed with the aid of a hydraulic dynamometer. It was noted that the use of the new manifold allowed the reduction on the backpressure. Concerning the maximum power registration there was no difference in terms of the original or the new manifold, because what had limited the power was the temperature on the turbine, which was set at 660 oC. Therefore, whenever the temperature reached this limit, the engine was deliberated stopped. This fact also explains why the ventilation has allowed higher engine powers. The new manifold resulted in fuel reductions.
O valor do kWh, no horário de pico, no Brasil, pode ser até nove vezes maior do que aquele cobrado, fora do dito período, estimulando a indústria, shopping centers, hotéis, etc. a fazerem uso de grupos geradores. Tais grupos são, em geral, compostos por motores a diesel e gerador elétrico. O lado negativo destes motores advém da larga poluição ambiental que produzem. Por sua vez, o Gás Natural, graças ao seu elevado poder calorífico e pela baixa contaminação, quando queimado, é considerado um combustível nobre, alternativo ao diesel. Assim, o uso de motores Diesel turbinados, convertidos para o ciclo Otto, pode reduzir significativamente a poluição ambiental. Nessa conversão, um dos aspectos observados é a influência da contrapressão causada pelo sistema de exaustão dos gases de escape, que contribui para o aumento da temperatura da turbina do motor convertido. O presente trabalho analisa os efeitos da substituição do coletor de escape original por outro, de curvas mais suaves, como também o resfriamento da turbina, no desempenho de um motor Perkins turboalimentado, modelo 1104C-44TAG2, ottolizado para gás natural. Os testes foram realizados com os dois coletores de escape, em operações com e sem refrigeração (por ventilação) da turbina e do coletor. A cada teste, eram avaliados: a potência máxima de operação, a temperatura dos gases de escape e o consumo do motor, em função da contrapressão do sistema de exaustão. Tais testes foram realizados, com o auxílio de um dinamômetro hidráulico, e os resultados mostraram que, de fato, houve uma redução da contrapressão, com a substituição do coletor. No entanto, o motor Perkins ottolizado respondeu, de forma semelhante, para os dois coletores, no que diz respeito à potência máxima alcançada, variando somente devido aos efeitos provocados com e sem resfriamento da turbina e do coletor. Deve-se observar, todavia, que a limitação no valor da potência deveu-se às temperaturas alcançadas pela turbina, de aproximadamente 660 °C. Assim, com resfriamento da turbina, o motor atingiu potências mais elevadas. Verificou-se, ainda, que a modificação do coletor contribuiu para a redução do consumo do motor.
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Junior, Alaercio Perotti. "Efeitos da informação verbal no acoplamento entre a informação visual e oscilação corporal." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/39/39132/tde-30102006-092030/.
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O objetivo desse estudo foi verificar os efeitos da manipulação de informação, visual proveniente de uma sala móvel, verbal fornecida sobre o movimento da sala e sobre uma ação solicitada, na oscilação corporal em crianças e adultos. Participaram deste estudo 20 crianças e 20 adultos jovens, que permaneceram na posição ereta dentro de uma sala móvel. Os resultados revelaram que a dinâmica intrínseca do sistema, referente ao relacionamento entre informação visual e oscilação corporal, não é facilmente modificada pela informação comportamental. A manipulação dos tipos de informação verbal, sobre movimento da sala e solicitação de uma ação, altera o relacionamento entre informação visual e oscilação corporal na situação da sala móvel. Entretanto, esta alteração requer atuação contínua do participante e, ainda, a solicitação de uma ação é mais efetiva nesta alteração do que somente a informação sobre o que está ocorrendo. Finalmente, há mudanças desenvolvimentais em como estas diferentes informações são utilizadas para o controle de uma ação motora. Enquanto adultos jovens utilizam as informações fornecidas de forma mais adequada para a ação solicitada, crianças apresentam dificuldade em utilizar a informação fornecida ou realizar uma ação solicitada frente à dinâmica intrínseca do sistema.The purpose of this study was to verify the effects of the manipulation of information, visual from a moving room, verbal informing about the movement of the room and about a requested action, in body sway of children and adults. Participated of this study 20 children and 20 young adults, who stood upright inside of a moving room. The results revealed that the system intrinsic dynamics, regarding the relationship between visual information and body sway, is not easily modified by behavioral information. The manipulation of the types of verbal information, about the moving room?s movement and requesting a specific action, alters the relationship between visual information and body sway in the moving room situation. However, this change requires the participant\'s continuous attention and, moreover, requesting an action is more effective than only the information about what is happening. Finally, there are behavioral changes in how these different types of information are used for the control of a motor action. While young adults use the provided information in a more appropriate way to perform the requested action, children show difficulty in order to use the provided information or to accomplish an action requested due to the intrinsic dynamics of the system.
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Fernandes, cardoso Juliana. "Démarche de pré-dimensionnement d’une machine électrique pour véhicule électrique : optimisation sur cycle de fonctionnement et avec contraintes de l’entraînement électrique." Thesis, Université Grenoble Alpes, 2020. https://thares.univ-grenoble-alpes.fr/2020GRALT046.pdf.
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Le problème environnemental est en train de changer la façon dont nous voyons nos besoins. Dans tous les secteurs d’activité humaine, de nouvelles solutions sont cherchées qui puissent permettre la durabilité de notre mode de vie. Dans ce contexte, le secteur du transport routier s’est tourné vers le véhicule électrique. Cette solution pose des défis, du point de vue de la conception du système de la chaîne de traction, liés à la complexité du système même et au cycle de fonctionnement du véhicule.Dans ce travail, nous proposons une méthodologie de préconception par optimisation de l’ensemble « machine électrique et onduleur de tension » prenant en compte le cycle de fonctionnement du système. Pour cela, nous développons un modèle semi-analytique d’une machine synchrone à aimants permanents et présentons un modèle analytique des pertes dans l’onduleur de tension. Nous développons ensuite une méthodologie de traitement des cycles de fonctionnement, afin de représenter un cycle complet par un nombre limité de points de fonctionnement. Finalement, nous utilisons les modèles créés et cette méthode de traitement afin de définir un problème d’optimisation. La solution de ce problème, en utilisant l’algorithme d’optimisation Sequential Quadratic Programming, permet le dimensionnement par optimisation d’une machine de référence pour différents cycles de fonctionnementThe environmental problem is changing the way to see our own needs. In order to make living the way we do sustainable, new solutions are being developed in every aspect of human life. In this context, the transport sector turned to the electrical vehicle. This technology is challenging from a powertrain design viewpoint, due mainly to the system complexity and the vehicle drive cycle.In this work, we propose a pre-design by optimization methodology for the electrical machine and the voltage inverter, considering a target drive cycle. In order to do so, we develop a semi-analytical model of a permanent magnet synchronous machine and present an analytical model of the voltage inverter losses. Then, we develop a method to simplify drive cycles so as to represent a whole cycle by a reduced number of operating points. Finally, we use the developed models and the cycle treatment method in order to create an optimization problem. By using the Sequential Quadratic Programming algorithm to solve this optimization problem, we perform the design by optimization of a reference machine considering different drive cycles
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Kubik, Martin. "Paroplynová elektrárna s spalovacími motory." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230040.
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The scope of this diploma thesis of focused on processing and calculation of the technological scheme for combi-cycle power plant with piston engine using heavy fuel oil. There are analyzed demands of piston engine for HFO and design of technological process preparation. This thesis analyzes the suitable locations, service options and alternative solution - heating plant with piston engines. Benefits of each option are assessed in the economic model, assuming power as a source of base load and providing support services. The results are intended to assess feasibility of the investment project.
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Muraro, Wilson. "Avaliação do funcionamento de motor ice com gas de baixo poder calorifico proveniente da gaseificação de casca de arroz." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264119.
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Orientador: Caio Glauco SanchezDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica.
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Resumo: Hoje no mundo há uma grande rejeição de matériais, resíduos e outros compostos orgânicos que podem ser aproveitados como fontes de energia. Exemplos podem ser observados em todo o mundo e principalmente em regiões onde a pobreza impera e que a energia elétrica pode ser de grande ajuda ou mesmo como um salva vidas. O emprego de pequenas centrais de geração de potencia integradas a um gaseificador comum motor de combustão interna (Integrated Gasefication Combustion EngineI GCE) do ciclo OTTO e adaptado para operar com gás de baixo poder calorífico, constitui uma alternativa interessante e economicamente viável,que possibilita a produção independente de energia elétrica e térmica (Marcelo,2004). Para o aproveitamento de resíduos de BIOMASSA,como a casca de arroz, utilizou-se um processo de gaseificação,que é uma técnica que possibilita o uso energético da biomassa através da obtenção de um gás de baixo poder calorífico (4a6 MJ/Nm33). Utilizou-se um gaseificador de leito fluidizado do Laboratório de combustão da FEM,onde foi instalado um motor de 5965 litros de cilindrada total e 6 cilindros, com taxa de compressão 12:1, do ciclo OTTO, que originalmente é utilizado em veículos movidos a gás natural comprimido. Obteve se os seguintes valores nos ensaios: Potência (kW)=40.7@ 1800 rpm, Avanço(Graus do virabrequim )=30;Temperatura de Escapamento (°C) =596; Lambda =1,12; Pressão Máxima de Combustão (PA) =4000000. Como funcionamento do motor, verificou se a necessidade de algumas alterações em seus componentes, como também mudanças nas regulagens de avanço. É necessário um sistema para aumentar a pressão do gás proveniente do gaseificador e um sistema de partida inicial. Dessa maneira teríamos um motor para operar como grupo gerador e fazer parte de uma planta piloto para geração de energia elétrica por gaseificação de biomassa
Abstract: Nowadays there is a great waste of organic matters, residues and other substances that could be used in a power plant. Examples can mainly be observed in the whole world and in regions where the poverty reigns and where the electric energy could be of great aid.The use of small power generation plants integrated to a gasification with an internal combustion engine (Integrated Gasification Combustion Engine-GCE) of cycle OTTO and adapted to operate with low power heat rate gas, consists an interesting and economical viable alternative, that makes possible the independent production of electric and thermal energy. For the exploitation of residues of BIOMASS, as the rice husk, we used a gasification process that is a form to increase the energy use of the biomass. The gasification can generate thermal energy and electric energy. It was used gasifier of fluidized bed from UNICAMP, where it was installed an engine with of 5,965 liters and 6 cylinders, with compression rate 12:1(cycle OTTO),which was originally used in vehicles powered by compressed natural gas, to running with the gas of low power heat rate (46 MJ/Nm3) produced by gasifier. Typical experimental result. Power (kW)=40,7@1800rpm; Advance (Degrees)=30; Exhaust gas temperature(°C)=596; Lambda=1,12; Maximum Combustion Pressure (PA)=4000000. During the running of the engine, the necessity of some alterations in some components was verified as well changes in the advance regulations. A system to increase the pressure of the gas proceeding from the gasifier and a system of start are necessary. In this way we would have an engine to operate as generating group and to be part of a pilot plant for generation of eletric energy for gasification of biomass in agricultural and interior cities
Mestrado
Termica e Fluidos
Mestre em Engenharia Mecânica
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Acquaviva, Alessandro. "Analytical Modeling of Iron Lossesfor a PM Traction Machine." Thesis, KTH, Elektrisk energiomvandling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105477.
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Permanent magnet (PM) machines offer several advantages in traction applications such as high efficiencyand high torque per volume ratio. The iron losses in these machines are estimated mostly with empiricallaws taken from other types of machines or with finite element simulations (FEM). In the first part of thisthesis the objective is to define an accurate analytical model for the stator yoke, teeth and rotor of a PMmotor which should work well enough for all operating point (different loads and frequency).This analytical model is found using an iterative process. After building a loss matrix and flux matrix basedon FEM simulations, it is possible to curve fit each of the lines or the rows of the matrix in order to achievethe best fitting for every operating point. This is a very new approach; it was shown that it gives thepossibility, even with a very limited number of FEM simulations, to achieve an accurate estimation of thelosses.The second part of this report focuses on optimizing this analytical method, comparing it with otherpossibilities, analyzing limits and advantages. Special attention is also given to the effects of the losses onthe temperatures in different parts of the machine. In the last part of the thesis, the analytical model isused to test a new control strategy. Its goal is to reduce the total losses of the motor and optimize the ratiobetween torque and total losses for a given driving cycle.
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Ercan, Taylan. "Thermodynamic And Structural Design And Analysis Of A Novel Turbo Rotary Engine." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606482/index.pdf.
Full textAbstract:
A novel turbo rotary engine, operating according to a novel thermodynamic
cycle, having an efficient compression phase, a limited temperature combustion
phase followed by a long power extraction phase is designed. Thermodynamic and
structural design and analysis of this novel engine is carried out and two prototypes
are manufactured according to these analysis. High performance figures such as
torque, power and low specific fuel consumption are calculated. Also the component
tests of the manufactured prototypes are completed and their results are
demonstrated.
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Costa, Fabiano Tadeu Mathias. "Estimação da relação ar-combustível utilizando o sinal de pressão no cilindro em um motor ciclo Otto a etanol." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-12022016-115907/.
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A crescente demanda de diminuição das emissões e redução do consumo dos motores de combustão interna exige a melhoria dos métodos para diagnose, em tempo real, e para melhor controle do processo de combustão. Portanto, é desejável determinar a relação ar-combustível sobre uma extensa faixa de condições de operação para obter um melhor controle do motor. Este trabalho apresenta a aplicação do Método dos Momentos para obtenção de um modelo de estimação da relação ar-combustível, através do sinal de pressão no cilindro, em um motor ciclo Otto a etanol. O modelo obtido permitirá o desenvolvimento de novos sistemas de controle utilizando como estratégia a pressão no cilindro.The increasing demands for low emission and low fuel consumption in internal combustion engines require improved methods for diagnosis, in real-time and best possible control of the combustion process. Therefore, determining air-fuel ratio over a wide range of engine operating conditions is desirable for better engine control. This work presents the Moment Method application for obtaining air-fuel ratio estimation model, by cylinder pressure sign, in Otto cycle engine powered by ethanol. The obtained model will allow the development of new control systems, for engine powered alcohol, using as strategy the cylinder pressure.
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Ozturk, Salih Baris. "Modelling, simulation and analysis of low-cost direct torque control of PMSM using hall-effect sensors." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/4905.
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This thesis focuses on the development of a novel Direct Torque Control (DTC) scheme for permanent magnet (PM) synchronous motors (surface and interior types) in the constant torque region with the help of cost-effective hall-effect sensors. This method requires no DC-link sensing, which is a mandatory matter in the conventional DTC drives, therefore it reduces the cost of a conventional DTC of a permanent magnet (PM) synchronous motor and also removes common problems including; resistance change effect, low speed and integration drift. Conventional DTC drives require at least one DC-link voltage sensor (or two on the motor terminals) and two current sensors because of the necessary estimation of position, speed, torque, and stator flux in the stationary reference frame. Unlike the conventional DTC drive, the proposed method uses the rotor reference frame because the rotor position is provided by the three hall-effect sensors and does not require expensive voltage sensors. Moreover, the proposed algorithm takes the acceleration and deceleration of the motor and torque disturbances into account to improve the speed and torque responses. The basic theory of operation for the proposed topology is presented. A mathematical model for the proposed DTC of the PMSM topology is developed. A simulation program written in MATLAB/SIMULINKî is used to verify the basic operation (performance) of the proposed topology. The mathematical model is capable of simulating the steady-state, as well as dynamic response even under heavy load conditions (e.g. transient load torque at ramp up). It is believed that the proposed system offers a reliable and low-cost solution for the emerging market of DTC for PMSM drives. Finally the proposed drive, considering the constant torque region operation, is applied to the agitation part of a laundry washing machine (operating in constant torque region) for speed performance comparison with the current low-cost agitation cycle speed control technique used by washing machine companies around the world.
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Zancanaro, Junior Flavio Vanderlei. "Análise numérica e experimental da combustão de metano em motores de combustão interna alternativos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/109158.
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Desde o seu surgimento o motor de combustão interna é a alternativa de fornecimento de potência mais utilizada no mundo em veículos de passeio e transporte de cargas. De fato, observa-se no dia-a-dia uma forte dependência da utilização de motores e, atualmente, os estudos visando o seu aumento de eficiência e a diminuição de emissões poluentes estão cada vez mais intensos. Com os grandes avanços ocorridos na disponibilização de computadores, existe uma tendência contínua para a utilização de técnicas computacionais auxiliando no projeto de motores. No entanto, o maior desafio é simular o escoamento altamente tridimensional, turbulento e transiente, com o uso de modelos de turbulência e combustão, que tenham bom compromisso com a física envolvida. Neste âmbito, o presente trabalho tem o objetivo de desenvolver uma validação de metodologias numérica e experimental, para avaliar o comportamento dinâmico e reativo do escoamento em motores de combustão interna. A simulação é aplicada a um motor Honda GX35, que possui vasto uso comercial em roçadeiras, motocicletas de baixo custo e, atualmente, em Veículos Autônomos Não Tripulados (VANT), dentre outros. A análise tem como base soluções numéricas pelo método dos volumes finitos, usando o programa comercial Star-cd/es-ice. Para resolver o escoamento turbulento o modelo adotado foi o k-ω SST, com aproximação para baixo Reynolds e tratamento de parede híbrido. O modelo de combustão ECFM-3Z foi empregado para resolver o escoamento reativo. O combustível utilizado foi metano em mistura estequiométrica. Os resultados numéricos são confrontados com resultados experimentais, com o objetivo de examinar o estado da arte dessas metodologias. Valores transientes de pressão no interior do cilindro, vazão mássica de ar, fração mássica queimada, em relação ao eixo de manivelas e os produtos da combustão são confrontados A presença de recirculações na admissão e no cilindro foram detectadas e discutidas. As evoluções da pressão interna no cilindro e da vazão mássica de ar resultantes da simulação numérica apresentaram um bom comportamento, quando confrontado com dados experimentais. Os resultados da fração mássica de combustível queimado revelam características importantes de funcionamento do motor.Since its inception, the internal combustion engine is the alternative of delivering power most used worldwide in passenger vehicles and transportation. Indeed, it is observed in day-to-day a strong dependency on the use of engines, and currently studies aiming at its increased efficiency and reduced emissions are becoming more intense. With the great advances in the availability of computers, there is a continuing trend towards the use of computational techniques aiding in the engine designs. However, the main challenge is to simulate the highly three-dimensional, transient and turbulent flows with the turbulence and combustion models, which have good compromise with the involved physics. In this context, this work aims to develop a validation of numerical and experimental methods for evaluating the dynamic and reactive behavior of the flow in internal combustion engines. The simulation is applied to a Honda GX35 engine, which has commercial application in brushcutters, motorcycles of low cost, Unmanned Autonomous Vehicles (UAV), among others. The analysis is based on numerical solutions by the finite volume method, using the commercial software Star-CD / esice. To solve the turbulent flow the model adopted was the k-ω SST, in its Low Reynolds approach with hybrid treatment near the walls The ECFM-3Z combustion model was employed to solve the reactive flow. The fuel used was methane in the stoichiometric mixture. The numerical results are compared with experimental ones, in order to examine the state of art of these methodologies. Transient values of cylinder inside pressure, mass air flow, mass fraction of the fuel burned, in relation to the crankshaft angle and the combustion products are confronted The presence of recirculation in the intake duct and cylinder were detected and discussed. The evolutions of the internal cylinder pressure and mass flow rate of air showed a good behavior, when confronted with experimental data. The results of the burned mass fraction reveal important characteristics of engine operation.
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Gallo, Michal. "Model Stirlingova motoru v PSCAD." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242000.
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This dissertation about the Stirling engine deals with the history and formation of the heat engine. At the beginning of this work, fundamental parts and their functions are described, elucidating the principle of operation explained by the thermodynamic cycle and subsequently comparing the ideal and the real Stirling cycle and last but not least provides various modifications whilst describing their differences. The mathematical model of the Stirling engine is processed by Schmidth’s theoretical analysis and thereafter is created in PScad v46. The process of creating a model is shown in one of the chapters of this dissertation. The results were taken into account in the design of 3D models in Inventor Professional by Autodesk. The work concludes with the evaluation of the computational model and its functionality as well as the documentation of the 3D model.
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Křepelka, Jan. "Numerický model řídicí jednotky spalovacího motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231326.
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Master’s thesis deals with issues of controlling the amount of fuel injected by the control unit. Model of four-cylinder engine and computational model of control unit were constructed in the simulation software Lotus Engine Simulation. Then was made model checking of the control unit by simulation two transients (acceleration and shifting). In conclusion was made application a created model on the New European Driving Cycle (NEDC) and appropriately evaluated and processed the results of this simulation.
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Malfatti, Laércio. "Análise qualitativa do ciclo real e tempo de combustão em um motor padrão ASTM-CFR operando com mistura de gasolina e etanol hidratado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/19041.
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A duração da combustão tem implicação direta na determinação do trabalho negativo no ciclo motor. A duração da combustão tem relação inversa com a velocidade de propagação da chama. Assim, quanto maior a velocidade de propagação da chama, menor a duração da combustão. Além disto, a duração da combustão está relacionada com a relação volumétrica de compressão, com a razão de mistura e com o tipo de combustível, entre outros fatores. Neste sentido, quanto maior a velocidade de queima da mistura ar-combustível, menor o trabalho negativo no ciclo. Neste contexto, foram ensaiadas 3 relações de compressão e 3 razões de mistura, para 6 combustíveis de composição conhecida: gasolina comum tipo C, álcool etílico hidratado combustível (AEHC) e AEHC adicionado à gasolina comum tipo C nas proporções de 20%, 40%, 60% e 80%. A variação da pressão no interior da câmara de combustão, para todos os combustíveis, e a posição da centelha de ignição foram determinadas com a utilização da base angular e com variação da relação volumétrica de compressão e da razão de mistura. O diagrama , para fins de cálculo de área, foi traçado por pós-processamento. Os resultados obtidos indicam que a duração da combustão aumenta com o aumento da razão de mistura e diminui com o aumento da relação volumétrica de compressão, para todos os combustíveis ensaiados. Verificou-se que a amplitude da pressão, no interior da câmara de combustão, se comporta inversamente à duração da combustão. Mostrou-se que o aumento da razão de mistura implica na redução do trabalho líquido entregue ao êmbolo ao longo de todo o ciclo do motor. Opostamente ocorre com o aumento da relação volumétrica de compressão, que implica no aumento do trabalho líquido por ciclo. Concluiu-se que o máximo valor para o trabalho líquido ao longo de todo o ciclo foi obtido para a maior relação volumétrica de compressão (8:1) e a menor razão de mistura (λ = 0,9). O combustível que representou este resultado foi o álcool etílico hidratado combustível adicionado à gasolina comum tipo C em 80% (AEHC80). O mínimo valor para o trabalho líquido, ao longo de todo o ciclo foi obtido, para a menor relação volumétrica de compressão (6:1) e a maior razão de mistura dos ensaios (λ = 1,1). O combustível que representou este resultado foi o álcool etílico hidratado combustível (AEHC).The duration of the combustion is directly implicative on determining the negative work of the motor cycle. The duration of the combustion has an inverse relation with the flame propagation speed. Thus, the higher propagation of the flame, the shorter duration of the combustion. Besides that, the duration of the combustion is related to the relation of compression, to the air/fuel relation and to the type of fuel, among other factors. In this way, the higher burning speed of the air/fuel mixture, the smallest negative work in the cycle. In such a context, there were tried three compression relations and three mixture ratios for six fuels of know compositions: ordinary gasoline C type, combustible hydrated ethyl alcohol and combustible hydrated ethyl alcohol added to ordinary gasoline C type in the proportions of 20%, 40%, 60% and 80%. The pressure variation inside the combustion chamber, for all fuels, and the position of the ignition spark were determined using the angular base and with variation of the compression relation and the mixture ratio. The diagram, for area calculation, was traced by post processing. The obtained results indicate that the combustion duration increases with the rising of the mixture ratio and decreases with the rising of the compression relation, for all the tried combustibles. It was found that the pressure amplitude inside the combustion chamber behaves inversely to the combustion duration behavior. It was shown that the rising of the mixture ratio implies on the reduction of the net work delivered by the piston all through the cycle of the motor. The opposite occurs with the rising of the compression relation, that implies on the increase of the net work by cycle. It was concluded that the maximum value for the net work all through the cycle was obtained for the higher compression relation (8:1) and the least mixture ratio of the tests (λ = 0,9). The combustible that achieved such a result was the combustible hydrated ethyl alcohol added to ordinary gasoline C type in 80%. The least value for the net work all through the cycle was obtained by the least compression relation (6:1) and the highest mixture ratio of the tests (λ = 1,1). The fuel that achieved that result was the combustible hydrated ethyl alcohol.
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Auñón, García Ángel. "Development and validation of a virtual engine model for simulating standard testing cycles." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/168906.
Full textAbstract:
[ES] Las nuevas regulaciones en materia de emisiones de efecto invernadero y calidad del aire han conducido la evolución tecnológica de los motores de combustión interna durante los últimos años. Las mejoras en el proceso de la combustión, la sobrealimentación, la gestión térmica, los sistemas de post tratamiento y técnicas como la recirculación de gases de escape, han permitido que los motores de combustión interna de hoy en día sean cada vez más limpios. La adopción en Europa del nuevo ciclo de homologación WLTP, que considera un ciclo de conducción más realista que su predecesor el NEDC, así como la necesidad de evaluar las emisiones contaminantes en diferentes escenarios de temperatura ambiente y de altitud, suponen un desafío para los fabricantes a la hora de diseñar y optimizar sus motores. En este contexto, el modelado unidimensional del motor ofrece la posibilidad de desarrollar y probar diferentes soluciones con la suficiente precisión,a la vez que permite agilizar el proceso de diseño del motor y reducir los costes de éste.
El objetivo de esta tesis es el de desarrollar un modelo completo de motor virtual que permita simular condiciones transitorias de régimen de giro y grado de carga, así como diferentes condiciones ambientales de presión y temperatura. Con este modelo de motor se pretende predecir las principales variables termo-fluidodinámicas en diferentes puntos del motor y las emisiones contaminantes liberadas en el escape.
Por otra parte, el arranque en frío y el funcionamiento a bajas temperaturas están asociados a un mayor consumo, mayores emisiones de hidrocarburos (HC) y monóxido de carbono (CO), así como mayores emisiones de óxidos de nitrógeno (NOx) debido a la desactivación de los sistemas de recirculación de gases de escape. Para paliar estos efectos adversos, una opción es lograr que el sistema de postratamiento alcance su temperatura de activación lo más pronto posible. En este trabajo se aborda este objetivo mediante dos soluciones. Por un lado, se ha explorado la posibilidad de elevar la temperatura de los gases en el escape mediante un sistema de distribución variable. Con este método se pueden reducir las emisiones de CO y HC en torno a un 40-50 % y las emisiones de NOx hasta un 15 % durante la primera fase del ciclo WLTC, a costa de una penalización en el consumo de combustible. Por otro lado, también se ha estudiado la posibilidad de aislar térmicamente el sistema de escape. En este caso, es posible reducir las emisiones de CO y HC en torno a un 30 % sin mejorar las de NOx.[CA] Les noves regulacions en matèria d'emissions d'efecte d'hivernacle i qualitat de l'aire han conduït la evolució tecnològica dels motors de combustió interna durant els darrers anys. Les millores en el procés de la combustió, la sobrealimentació, la gestió tèrmica, els sistemes de postractament i tècniques com la recirculació de gasos d'escapament, han permès que els motors de combustió interna d'avui dia siguen cada vegada més nets. L'adopció a Europa del nou cicle d'homologació WLTP, que considera un cicle de conducció més realista que el seu predecessor el NEDC, així com la necessitat d'avaluar les emissions de gasos contaminants en diferents escenaris de temperatura ambient i humitat, suposen un repte per als fabricants a l'hora de dissenyar i optimitzar els seus motors. En aquest context, el modelatge unidimensional del motor ofereix la possibilitat de desenvolupar i provar diferents solucions amb la suficient precisió, al mateix temps que agilitza el procés de disseny del motor i reduïx els costos derivats d'aquest. L'objectiu d'aquesta tesi és el de desenvolupar un model complete de motor virtual que permeta simular condicions transitòries de règim de gir i grau de càrrega, així com diferents condicions ambientals de pressió i temperatura. Amb aquest model de motor es pretén predir les principals variables termo-fluidodinàmiques en diferents punts del motor i les emissions contaminants alliberades en l'escapament. Per altra banda, l'arrancada en fred i el funcionament a baixes temperatures están associats a un major consum, majors emissions d'hidrocarburs (HC) i monòxid de carboni (CO), així com majors emissions d'òxids de nitrògen (NOx) degudes a la desactivació dels sistemes de recirculació de gasos d'escapament. Per a pal·liar aquestos efectes indesitjats, una opció és aconseguir que el sistema de postractament arribe a la seua temperatura d'activació el més prompte possible. En aquest treball, aquest objectiu s'aborda mitjançant dues solucions. Per una banda, s'ha investigat la possibilitat d'augmentar la temperatura dels gasos en l'escapament per mitjà d'un sistema de distribució variable. Amb aquest mètode s'ha aconseguit reduïr les emissions de CO i HC al voltant d'un 40-50 % i les emissions de NOx fins a un 15 % durant la primera fase del cicle WLTC, acosta d'una penalització en el consum de combustible. Per altra banda, també s'ha estudiat la possibilitat d'aïllar tèrmicament el sistema d'escapament. En aquest cas, és possible reduir les emissions de CO i HC vora un 30 % sense millorar les de NOx .
[EN] The new regulations regarding greenhouse emissions and air quality have led the technological progress of the internal combustion engines during the recent years. Improvements in the combustion process, turbocharging, thermal management, after-treatment systems and techniques such as the exhaust gases recirculation, have resulted in cleaner internal combustion engines. The adoption of the new type approval test in Europe, so-called WLTP, which represents a more realistic driving cycle than its forerunner the NEDC, as well as the need to evaluate pollutant emissions at different conditions of ambient temperature and altitude, represent a challenge for manufacturers when it comes to design and optimise their engines. In this context, one-dimensional engine models offer the possibility to develop and test different solutions with enough accuracy, while hastening the engine design process and reducing its costs. The main objective of this thesis is to develop a complete virtual engine model able to simulate transient conditions of engine speed and load, as well as different ambient conditions of pressure and temperature. The engine model is used to predict the main thermo-and fluid dynamic variables at different engine locations and the tailpipe pollutant emissions. Furthermore, engine cold start and its operation at low temperature is associated to a greater fuel consumption, hydrocarbon (HC) and carbon monoxide (CO) emissions; as well as more nitrogen oxide (NOx) emissions due to the deactivation of the exhaust gases recirculation systems. A solution to mitigate these negative effects is to heat up the after-treatment system so as to achieve its activation temperature as soon as possible. In the work presented, this goal is addressed through two different standpoints. On the one hand, variable valve timing systems have been studied as a way to increase the exhaust gases temperature. With this option it is possible to reduce CO and HC emissions by 40-50 % and NOx emissions by 15 % during the first stage of the WLTC cycle, at the expense of a penalty in the fuel consumption. On the other hand, the thermal insulation of the exhaust system has also been studied with the same objective. In this case, it is possible to reduce CO and HC emissions by 30 %, while not improving NOx ones.
The author wishes to acknowledge the financial support received through the FPI S2 2018 1048 grant of Programa de Apoyo para la Investigación y Desarrollo (PAID) of Universitat Politècnica de València.
Auñón García, Á. (2021). Development and validation of a virtual engine model for simulating standard testing cycles [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/168906
TESIS