Tesi sul tema "Internal Combustion Engines"
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1
Bishop, Robert Phelps. "Combustion efficiency in internal combustion engines". Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15164.
Testo completoAbstract (sommario):
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaf 26.
by Robert Phelps Bishop.
B.S.
2
Yang, Lisheng. "Friction modelling for internal combustion engines". Thesis, University of Leeds, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343482.
Testo completo
3
Clarke, Ralph Henry. "Heat losses in internal combustion engines". Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/8290.
Testo completoAbstract (sommario):
Bibliography: leaves 119-121.This thesis deals with the effects of cooling and heat losses in internal combustion engines. The object of this work was to examine and research various cooling concepts and methods to reduce heat loss to engine coolant, improve thermal efficiency and to predict heat transfer values for these alternatives. The optimum system to be considered for possible application to small rural stationary engines. A literature survey was undertaken, covering work performed in the field of internal combustion engine cooling. Besides the conventional cooling system, two concepts emerged for consideration. These were the precision cooling system and the new heat pipe concept, the latter being relatively unknown for internal combustion cooling application. The precision cooling system, consists of a series of small bore tubes conducting coolant only to the critical areas of an engine. The theory being that in the conventional systems many regions are overcooled, resulting in excessive heat loss. The heat pipe is a device of very high thermal conductance and normally consists of a sealed tube containing a small quantity of fluid. Under operating conditions the tubular container becomes an evaporator region in the heat input area and a condenser region in the heat-out area. It is therefore basically a thermal flux transformer,attached to the object to be cooled. The heat pipe performance is also capable of being modulated by varying its system pressure. This is a positive feature for internal combustion engine application in controlling detonation and NOx emissions. Various facts were obtained from the literature survey and considered in the theoretical review. These facts were extended into models, predicting the heat transfer performance of each concept in terms of coolant heat outflow and heat transfer coefficients. The experimental apparatus was based on an automotive cylinder head with heated oil passing through the combustion chamber and exhaust port to simulate combustion gases. Experiments were conducted on this apparatus to validate the predicted theoretical performance of the three concepts. Tests were also made to observe the effect of heat pipe modulation and nucleate boiling in the precision system. Concept theory was validated as shown by the experimental and test results. The performance for each system approximated the predicted heat transfer and heat loss values. By comparison of the heat input, coolant heat outflow values and heat transfer coefficients it was found that the precision system was the most efficient, followed by the heat pipe and the conventional system being the least efficient. It was concluded that the heat loss tests provided a valuable insight into the heat transfer phenomenon as applied to the three systems investigated. This work also illustrated the effects of the variation of coolant flow, velocity and influence of nucleate boiling. This thesis has shown the potential of the systems tested, for controlling heat losses in internal combustion engines. The research work has created a data base for further in-depth evaluation and development of the heat pipe and the precision cooling system. Based on the findings of the experimental work done on this project, several commercial applications exist for the heat pipe and precision cooling systems. Further in-depth research is recommended to extend their potential in the automotive industry.
4
Mitchell, Tom. "Advanced thermal management for internal combustion engines". Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193080144/.
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5
Ward, Matthew. "Automatic-calibration methods for internal combustion engines". Thesis, University of Bath, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418598.
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6
Sone, Kazuo. "Unsteady simulations of mixing and combustion in internal combustion engines". Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/12171.
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7
Shah, Priti. "Mathematical modelling of flow and combustion in internal combustion engines". Thesis, University of Greenwich, 1989. http://gala.gre.ac.uk/8703/.
Testo completoAbstract (sommario):
The research work reported herein addresses the problem of mathematical modelling of fluid flow and combustion in internal combustion engines. In particular, the investigation of three topics that constitute prime sources of uncertainty, in current numerical models, namely turbulence modelling, inaccuracies in the solution procedure specific to moving grids, and combustion modelling. Two and three-dimensional computations of the in-cylinder turbulent flow in a diesel engine are described first, with emphasis on the modifications made to the standard k- model of turbulence to account for rapid compression/expansion, and on the k-W model also used in the computations. It is concluded that the standard k- model may lead to poor predictions when used for internal combustion engine simulations, and that the modified model leads to more reasonable length-scale distributions, improving significantly the overall agreement of velocity predictions with experiment. It is also demonstrated that the k-W model provides better turbulence predictions than the unmodified k- model for the cases considered. The moving boundary within a reciprocating engine poses the problem that as it moves toward the cylinder head it compresses the computational grid cells, creating large aspect ratios that can adversely affect the numerical accuracy and convergence. A conservative scheme has therefore been devised that allows for the removal or addition of grid cells during the simulation, so as to maintain reasonable aspect ratios. It is concluded that with the proposed scheme convergence is obtained within fewer iterations, computational cost is therefore reduced, and that the results are generally in better agreement with experimental data. The third part of this study investigates and compares the performance of the two most commonly used combustion models (the eddy-break-up and the Arrhenius models) and proposes a new formulation of a flame-front model. Calculations have been performed for a one-dimensional test case and for a representative spark-ignition engine in order to determine the grid and time step requirements for numerical accuracy, the sensitivity of results to empirical input and the physical realism of the predictions by comparison with experimental data. It has been found for the cases considered that neither the eddy-break-up nor the Arrhenius models are appropriate for predicting engine combustion. The Arrhenius model does not represent well the combustion process for the cases considered. The eddy-break-up model is not capable of predicting the observed flame front, and the empirical constants in the model require extensive tuning to obtain predictions that match experiments. The flame-front model however, in spite of many simplifications, produces much more realistic flame-front propagation and the empirical input of the model, i.e. the flame speed, can in principle be obtained by other means other than ad-hoc tuning. It is concluded that the flame-front model requires refinement, but for the cases considered, it provides the basis of a very promising combustion model for predicting premixed combustion in engines.
8
Seward, Balaji B. "Small engine emissions testing laboratory development and emissions sampling system verification". Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11024.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains xvi, 110 p. : ill. Includes abstract. Includes bibliographical references (p. 108-110).
9
Ma, Jia. "Model-based control of electro-pneumatic intake and exhaust valve actuators for IC engines". Diss., Connect to online resource - MSU authorized users, 2008.
Cerca il testo completoAbstract (sommario):
Thesis (Ph. D.)--Michigan State University. Dept. of Mechanical Engineering, 2008.Title from PDF t.p. (viewed on Mar. 31, 2009) Includes bibliographical references (p. 150-151). Also issued in print.
10
Fleck, R. "Predicting the performance characteristics of internal combustion engines". Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431397.
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11
Giles, Anthony Peter. "Alternative fuels and technology for internal combustion engines". Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56090/.
Testo completoAbstract (sommario):
Within this thesis is an investigation and appraisal of alternative automotive fuels, internal combustion engine technology and emission reduction techniques. A review of the developments in engine technology, with specific focus on improvements in engine efficiency and emission reductions was undertaken. Tighter emission legislation imposed after the Kyoto agreement has resulted in technological advances in the field of internal combustion engines improving the economy of modern motor vehicles while reducing their emissions of C02 and particulate matter. As part of an EU funded project entitled "Magnetic Movement Valve for Miller Cycle operation of engines", the application of a novel secondary valve apparatus to an internal combustion engine was investigated through the use of computer modelling. It was shown that the secondary valve concept is capable of controlling the output of an internal combustion engine, while increasing the operating efficiency and reducing the emission of NOx through the use of Miller cycle operation and throttle free load control. A development programme of the engine and the secondary valve apparatus, carried out in conjunction with EU project partners, resulted in a marketable engine incorporating the new technology which is now in production within Europe and the Far East. An engine test-bed facility was commissioned to investigate the emissions and performance of a diesel engine fuelled by a variety of biodiesel / diesel fuel blends. It was found that incremental addition of biodiesel to a low sulphur diesel fuel resulted in a decrease in engine power and an increase in fuel consumption, CO2 and NOx emissions. The particulates levels of pure biodiesel emissions were found to be much lower (by mass and number concentration) than that of the low sulphur diesel fuel. From analysis of the exhaust gases it was found that the average size of the particulates is larger for biodiesel fuel than for the low sulphur diesel fuel.
12
Bai, Dongfang Ph D. Massachusetts Institute of Technology. "Modeling piston skirt lubrication in internal combustion engines". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74901.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 143-147).
Ever-increasing demand for reduction of the undesirable emissions from the internal combustion engines propels broader effort in auto industry to design more fuel efficient engines. One of the major focuses is the reduction of engine mechanical losses, to which the friction of the piston skirt is one important contributor. Yet there lacks a sufficient understanding of the skirt lubrication behavior to effectively optimize the piston skirt system in practice. The ultimate goal of this work is to develop a comprehensive model to advance the predictability of the skirt friction while integrating all the dynamic behavior of the piston secondary motion and the structural deformation of the piston skirt and cylinder liner. Major contributions of this work are analysis of and development of a model for the oil transport and exchange of the piston skirt region and its surroundings. The new oil transport model is composed with two elements. First, the oil scraped into the chamfer region by the oil control ring during a down-stroke is tracked and its accumulation and release to the skirt region are modeled. Second, oil separation and re-attachment are allowed in the skirt region, breaking conventional full-attachment assumption in lubrication studies. The new oil transport model together with hydrodynamic and boundary lubrication model were coupled with piston secondary motion and structural deformation of the piston skirt and cylinder liner. For numerical efficiency and physics clarity, we used different discretization for the lubrication from the structural deformation. The final model is robust and efficient. The discussion of the model results is focused mainly on the oil transport. There exist a general pattern in available oil for skirt lubrication, namely, skirt tends to be starved when it travels at the upper portion of a stroke. Comparison with visualization experiment for oil accumulation patterns show consistency between model prediction and observation. This work represents a major step forward to realistically predicting skirt friction and the influence of all the relevant design and operational parameters. However, oil supply to the region below the piston skirt can largely influence the outcome of the friction prediction and its mechanism is system dependent. Additionally, simple treatment of the oil transport in the current model is merely a first step to modeling the complex fluid problems involved. Improvements of this model based on application and further analysis will make it a more powerful engineering tool to optimize the skirt system to minimize its undesirable outputs.
by Dongfang Bai.
Ph.D.
13
Wijewardane, M. Anusha. "Exhaust system energy management of internal combustion engines". Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9829.
Testo completoAbstract (sommario):
Today, the investigation of fuel economy improvements in internal combustion engines (ICEs) has become the most significant research interest among the automobile manufacturers and researchers. The scarcity of natural resources, progressively increasing oil prices, carbon dioxide taxation and stringent emission regulations all make fuel economy research relevant and compelling. The enhancement of engine performance solely using incylinder techniques is proving increasingly difficult and as a consequence the concept of exhaust energy recovery has emerged as an area of considerable interest. Three main energy recovery systems have been identified that are at various stages of investigation. Vapour power bottoming cycles and turbo-compounding devices have already been applied in commercially available marine engines and automobiles. Although the fuel economy benefits are substantial, system design implications have limited their adaptation due to the additional components and the complexity of the resulting system. In this context, thermo-electric (TE) generation systems, though still in their infancy for vehicle applications have been identified as attractive, promising and solid state candidates of low complexity. The performance of these devices is limited to the relative infancy of materials investigations and module architectures. There is great potential to be explored. The initial modelling work reported in this study shows that with current materials and construction technology, thermo-electric devices could be produced to displace the alternator of the light duty vehicles, providing the fuel economy benefits of 3.9%-4.7% for passenger cars and 7.4% for passenger buses. More efficient thermo-electric materials could increase the fuel economy significantly resulting in a substantially improved business case. The dynamic behaviour of the thermo-electric generator (TEG) applied in both, main exhaust gas stream and exhaust gas recirculation (EGR) path of light duty and heavy duty engines were studied through a series of experimental and modelling programs. The analyses of the thermo-electric generation systems have highlighted the need for advanced heat exchanger design as well as the improved materials to enhance the performance of these systems. These research requirements led to the need for a systems evaluation technique typified by hardware-in-the-loop (HIL) testing method to evaluate heat exchange and materials options. HIL methods have been used during this study to estimate both the output power and the exhaust back pressure created by the device. The work has established the feasibility of a new approach to heat exchange devices for thermo-electric systems. Based on design projections and the predicted performance of new materials, the potential to match the performance of established heat recovery methods has been demonstrated.
14
Morgan, Tessa Joanne. "The modelling of internal combustion engine thermal systems and behaviour". Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/12225/.
Testo completoAbstract (sommario):
The work described in this thesis concerns the continued development and application of a computational model to simulate the thermal behaviour of internal combustion engines. The model provides information on temperature and heat flow distributions within the engine structure, and on temperatures of oil, coolant and engine-out exhaust gas. Sub-models calculate friction levels, fuel flow rates and gas-side heat transfer, including the effects of exhaust gas recirculation (EGR), spark advance and turbocharging. The effects of auxiliary components such as a cabin heater, oil cooler, intercooler, supplementary heater and EGR cooler can also be simulated. Model developments are aligned towards improving the accessibility of the model and the scope of engine systems that can be simulated. Early versions of the model have been converted from 'C' into the current MATLAB/Simulink versions. The model structure and conversion process are described. New developments undertaken have focused on the external coolant circuit and include the modelling of the thermostat and radiator. A semi-empirical thermostat model is presented. A radiator model based on the effectiveness-NTU method is described. Simulations using the developed model, including the thermostat and radiator sub-models, investigate the effect of thermostat position on engine thermal behaviour. Positioning the thermostat on the inlet to the engine reduces thermal shock. Applications of the model to investigations of sensitivity and performance illustrate the accuracy of and confidence in model predictions. Assessments demonstrate that the model is relatively insensitive to variations of 100/0 in user inputs and is very sensitive to model assumptions if simulation conditions, implied in the model assumptions, are not matched to test conditions. A process for evaluating model performance is described. Evaluation exercises applied to three different engines demonstrate that values predicted by the model are to within 5 to 10% of experimental values. Investigations using the model of methods to improve warm-up times and fuel consumption prior to fully warm conditions show the benefits or otherwise of reduced thermal capacity, an oil cooler, a sump oil heater and an oil-exhaust gas heat exchanger. Each method is assessed over the New European Drive Cycle (NEDC) from a -10°C start. Of these methods, a combined reduction in coolant volume and engine structural mass is most beneficial for reducing coolant warm-up times. An oil-exhaust gas heat exchanger produces the greatest reduction in fuel consumption.
15
Petreanu, Sorin. "Conceptual analysis of a four-stroke linear engine". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2084.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xii, 126 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 122-126).
16
Milovanović, Nebojša. "A study of controlled auto ignition (CAI) combustion in internal combustion engines". Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/19906.
Testo completoAbstract (sommario):
Controlled Auto Ignition (CAI) combustion is a new combustion principle in internal combustion engines which has in recent years attracted increased attention. In CAI combustion, which combines features of spark ignition (SI) and compression ignition (CI) principles, air/fuel mixture is premixed, as in SI combustion and auto-ignited by piston compression as in CI combustion. Ignition is provided in multiple points, and thus the charge gives a simultaneous energy release. This results in uniform and simultaneous auto-ignition and chemical reaction throughout the whole charge without flame propagation. CAI combustion is controlled by the chemical kinetics of air/fuel mixture with no influence of turbulence. The CAI engine offers benefits in comparison to spark ignited and compression ignited engines in higher efficiency due to elimination of throttling losses at part and idle loads. There is a possibility to use high compression ratios since it is not knock limited, and in significant lower NOx emission (≈90%) and particle matter emission (≈50%), due to much lower combustion temperature and elimination of fuel rich zones. However, there are several disadvantages of the CAI engine that limits its practical application, such as high level of hydrocarbon and carbon monoxide emissions, high peak pressures, high rates of heat release, reduced power per displacement and difficulties in starting and controlling the engine. Controlling the operation over a wide range of loads and speeds is probably the major difficulty facing CAI engines. Controlling is actually two-components as it consists of auto-ignition phasing and controlling the rates of heat release. As CAI combustion is controlled by chemical kinetics of air/fuel mixture, the auto-ignition timing and heat release rate are determined by the charge properties such as temperature, composition and pressure. Therefore, changes in engine operational parameters or in types of fuel, results in changing of the charge properties. Hence, the auto-ignition timing and the rate of heat release. The Thesis investigates a controlled auto-ignition (CAI) combustion in internal combustion engines suitable for transport applications. The CAI engine environment is simulated by using a single-zone, homogeneous reactor model with a time variable volume according to the slider-crank relationship. The model uses detailed chemical kinetics and distributed heat transfer losses according to Woschini's correlation [1]. The fundamentals of chemical kinetics, and their relationship with combustion related problems are presented. The phenomenology and principles of auto-ignition process itself and its characteristics in CAI combustion are explained. The simulation model for representing CAI engine environment is established and calibrated with respect to the experimental data. The influences of fuel composition on the auto-ignition timing and the rate of heat release in a CAI engine are investigated. The effects of engine parameters on CAI combustion in different engine concepts fuelled with various fuels are analysed. The effects of internal gas recirculation (IEGR) in controlling the auto-ignition timing and the heat release rate in a CAI engine fuelled with different fuels are investigated. The effects of variable valve timings strategy on gas exchange process in CAI engine fuelled with commercial gasoline (95RON) are analysed.
17
Mendes, Alexandre Schalch. "Desenvolvimento e validação de metodologia para analise de vibrações torcionais em motores de combustão interna". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264376.
Testo completoAbstract (sommario):
Orientadores: Pablo Siqueira Meirelles, Douglas E. ZampieriDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Este trabalho tem como objetivo a análise do fenômeno das vibrações torcionais em árvores de manivelas de motores de combustão interna para aplicações veiculares. Como exemplo, a formulação proposta será aplicada no estudo da árvore de manivelas de um motor fabricado pela empresa MWM Motores Diesel Ltda., de seis cilindros em linha, quatro tempos, considerando-se a utilização de um amortecedor de vibrações de material elastomérico acoplado ao componente. Da análise das vibrações torcionais é possível de se obter os torques atuantes em cada secção do virabrequim. Estes esforços poderão ser aplicados posteriormente como condições de contorno a um modelo de elementos finitos, para que juntamente aos demais carregamentos existentes, seja feita a verificação do ciclo de fadiga atuante, de modo a avaliar o coeficiente de segurança do componente. Apesar de não ser este o foco deste trabalho, pode-se notar a importância da análise das vibrações torcionais no dimensionamento estrutural de uma árvore de manivelas. Iremos comparar as amplitudes de vibrações torcionais teóricas às obtidas experimentalmente, para a validação do modelo matemático proposto
Abstract: The scope of this work is the study of the crankshaft torsional vibration phenomenon for internal combustion engines. As an example, the formulation will be applied to an engine for a vehicular application, manufactured by MWM Motores Diesel Ltda., with six cylinders in line configuration, four strokes and considering a rubber damper assembled to the component. From the torsional vibrations analysis, it is possible to ca1culatethe actuating torque in each crankshaft section. These loads can be applied as boundary conditions to a finite element model and with the consideration of the other existing loads it is possible to determine the fatigue cyc1e,to calculate the safety factor ofthe component. This is not the objective ofthis work, but it is possible to note the importance of the torsional vibrations analysis in the structural dimensioning of the crankshafts. The obtained results by the presented methodology will be compared to the measured values for the validation of the proposed mathematical model
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
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Rodrigues, Alex de Souza 1979. "Análise dinâmica e balanceamento de virabrequins leves de motores". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263509.
Testo completoAbstract (sommario):
Orientador: Marco Lúcio BittencourtDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Devido às atuais exigências de leis de emissão e redução de consumo de combustível, busca-se reduzir o peso dos componentes sem impacto aos critérios de projeto. Neste sentido, torna-se importante entender e discutir os critérios de projeto do componente em estudo. Este trabalho tem por objetivo entender a influência da redução do contrapeso de uma árvore de manivelas quatro cilindros em linha. Assim, para analisar o impacto da redução de massa nos contrapesos, foi realizado um estudo de sensibilidade nesta região do componente. Para analisar esta viabilidade, foram discutidos alguns critérios de balanceamento e a dinâmica do virabrequim em operação no motor. Nestas metodologias de balanceamento, resumiu-se a teoria básica mais comumente utilizada. Neste trabalho, aplicou-se o conjunto de ferramentas analisadas em um estudo de caso para um virabrequim forjado de um motor quatro cilindros em linha, obtendo-se a diferença dos critérios de balanceamento utilizados em relação à análise dinâmica. Foi observado que há critério de balanceamento que não considera efeito dinâmico importante. Finalmente, demonstrou-se que quando se deseja ter um contrapeso leve, existem alternativas de geometria que minimizam o impacto da retirada de massa
Abstract: Due to the current emission standard and fuel consumption requirements, lightweight components with no impact in the design criterion are desired. As a consequence, it is vital to understand and discuss the design criteria of the studied component. This work aims to understand the influence of crankshaft counterweight reduction in an inline-four cylinder engine. Thus, to analyze the counterweight mass reduction, it was done a sensitivity study at this region. In order to analyze this feasibility, it was discussed some balancing criteria and also the crankshaft under virtual engine operation. In these balancing methodologies, it was summarized the basic theory usually designed. In this work, it was applied a package of tools in a study of case for a 4cyl. in-line engine crankshaft, obtaining the difference between some balancing methods versus the dynamics analysis. It was noticed that there are balancing methodologies which do not mind important dynamics effect. All in all, it was showed that if a lightweight design is desired, there are some ways to minimize the unbalancing impact when saving counterweight mass
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
19
Menon, Shyam Kumar. "Performance measurement and scaling in small internal combustion engines". College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3589.
Testo completoAbstract (sommario):
Thesis (M.S.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Leong, David Kok Wei. "Investigations of friction losses in automotive internal combustion engines". Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408635.
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Meng, Zhen Ph D. Massachusetts Institute of Technology. "Modeling of piston pin lubrication in internal combustion engines". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129019.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 120-121).
The piston pin joins the piston and the connecting rod to transfer the linear force on the piston to rotate the crankshaft that is the eventual power outlet of the engine. The interfaces between the piston pin and the pin bore as well as the connecting rod small end are one of the most heavily loaded tribo pairs in engines. Piston pin seizure still occurs often in the engine development and the solution often comes from applying expensive coatings. Furthermore, it has been found that the friction loss associated with the pin can be a significant contributor to the total engine mechanical loss. Yet, there lacks a basic understanding of the lubrication behavior of the pin interfaces. This work is aimed to develop a piston pin lubrication model with consideration of all the important mechanical processes. The model predicts the dynamics of the pin and the lubrication of the interfaces between the pin and pin bore as well as small end.
The model couples the dynamics of the pin with the structural deformation of the mating parts, the hydrodynamic and boundary lubrication of all the interfaces, and oil transport. The model is successfully implemented with an efficient and robust numerical solver with the second order accuracy to compute this highly stiff system. The preliminary results applying the model to a gasoline engine show that the boundary lubrication is the predominant contributor to the total friction. As a result, the interface with more asperity contact tends to hold the pin with it. Thus, the pin friction loss is coming from the interface with less contact. Solely from friction reduction point of view, ensuring efficient hydrodynamics lubrication in one interface is sufficient.
Furthermore, as the heavy load is supported in several small areas, mechanical and thermal deformation of all the parts are critical to load distribution, oil transport, and the generation of hydrodynamic and asperity contact pressure, providing the necessity of the elements integrated in the model. This work represents the first step to establishing a more comprehensive engineering model that helps the industry understand the pin lubrication and find cost-effective solutions to overcome the existing challenges.
by Zhen Meng.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
22
Mamani, A., G. Quispe e C. Raymundo-Ibañeez. "Electromechanical Device for Temperature Control of Internal Combustion Engines". IOP Publishing Ltd, 2019. http://hdl.handle.net/10757/656303.
Testo completoAbstract (sommario):
Internal combustion engines are the most commonly used engines in the automotive world. However, these engines lack an overheating prevention system against cooling system failures when they exceed their normal operating temperature. Less experienced drivers (users) usually do not notice overheating until the engine stops, generating economic expenses in engine repairs. As such, this paper describes the design and construction of an electromechanical device to prevent engine overheating. This device is installed in a vehicle and operates independently from the electronic control unit (ECU); it records the coolant temperature and controls air admission to the engine of the vehicle in which it is installed. In addition, a new Arduino-based card will receive signals from a temperature sensor as input and process them according to its programming. Then, it will send signal outputs to the actuators: A servomotor, monitor, LED display, and buzzer. To control the intake flow, a butterfly valve is used with the servomotor. This valve partially or totally restricts the engine airflow, based on the temperature programmed for the Arduino, thus protecting the engine from overheating.
23
Moreira, José Francisco Pereira. "Q'@gile : quantum agile manufacture of internal combustion engines". Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/34546.
Testo completoAbstract (sommario):
Current trends in the automotive industry towards fuel efficient and low emission vehicles, are dictated by more environmental friendly customers, more strict environmental legislation, rising fuel costs and intensive competition. These factors are pressuring vehicle manufacturers to speed up R&D and improve the efficiency and flexibility of their manufacturing operations so that improved products can be introduced over shortened timeframes. Recent advances have been focused on improving the design of internal combustion engines, coupled with research into alternative fuels and related new forms of vehicle propulsion. Natural impacts of these advances have been shorter engine lifetimes, increased pace of engine innovations, and significant changes in propulsion type share: in Europe the diesel engine share is increasing relative to that of petrol engines while in the US and Japan hybrids are becoming popular. In the long-term fuel cell- and hydrogen-fuelled vehicles may largely make internal combustion engines obsolete.
24
Ribeiro, Mateus Dias. "Fuel spray modeling for application in internal combustion engines /". Guaratinguetá, 2019. http://hdl.handle.net/11449/183102.
Testo completoAbstract (sommario):
Orientador: José Antônio Perrella BalestieriAbstract: Direct injection spark ignition (DISI) engines aim at reducing specific fuel consumption and achieving the strict emission standards in state of the art internal combustion engines. Therefore, in this work the goal is to develop code for simulations of the internal flow in DISI engines, as well as the phenomenon of fuel spray injection into the combustion chamber using a Lagrangian-Eulerian approach for representing the multiphase flow, and Large-eddy Simulations (LES) for modeling the turbulence of the continuum medium by means of the open-source CFD library OpenFOAM. In order to validate the obtained results and the developed models, experimental data from the Darmstadt optical engine, and the non-reactive “Spray G” gasoline injection case, along with the reactive “Spray A” case from the Engine Combustion Network (ECN) will be employed. Finally, a novel open-source solver will be proposed to simulate the Darmstadt optical engine in motored and fired operation under stratified mixture condition, using data compiled by the Darmstadt Engine Workshop (DEW) for validation. Moreover, a deep learning framework is presented to train an artificial neural network (ANN) with the engine LES data generated in this work, in order to make predictions of the small scale turbulence behavior.
Resumo: Motores de ignição a centelha com injeção direta (direct injection spark ignition engines, DISI engines) visam reduzir o consumo específico de combustível e respeitar os restritos níveis de emissão em motores de combustão interna de última geração. Assim, pretende-se com este trabalho desenvolver código para simulação do escoamento interno em motores DISI, assim como os fenômenos de injeção de combustível no interior da câmara de combustão utilizando uma abordagem Lagrangeana-Euleriana para representação do escoamento multifásico e Simulação de Grandes Escalas (Large-eddy simulation, LES) para a modelagem da turbulência no meio contínuo, por intermédio da biblioteca CFD de código aberto OpenFOAM. De modo a validar os resultados e os modelos desenvolvidos, dados experimentais serão utilizados, obtidos do motor óptico de Darmstadt, e do caso de teste de injeção de gasolina não-reativo “Spray G”, juntamente com o caso reativo “Spray A” da Rede de Combustão em Motores (Engine Combustion Network, ECN). Enfim, um novo código aberto será proposto para simular o motor óptico de Darmstadt em condições de escoamento a frio (sem combustão) e com combustão em condição de mistura estratificada, usando dados compilados pelo Workshop do Motor de Darmstadt (Darmstadt Engine Workshop, DEW) para validação. Além disso, uma abordagem de aprendizado profundo (deep learning) será apresentada para treinar uma rede neural artificial (artificial neural network, ANN) com dados de simulação LES de moto... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
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Blomgren, Niklas. "Decoupled Design of Auxiliary Systems for Internal Combustion Engines". Thesis, Linköpings universitet, Fluida och mekatroniska system, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123991.
Testo completoAbstract (sommario):
This thesis investigated if decoupled design of the air intake and exhaust systems for four-stroke internal combustion engines is possible. Using the information found design guidelines were set up for the formula student team ELiTH Racing. The literature study revealed that the systems are not uncoupled, and the inuence of exhaust geometry on air intake behavior needed more thorough investigation. Experiments were designed, using a single cylinder engine with simple intake and exhaust geometries. The tests were attempted, but had to be abandoned due to time constraints. Successful tests would have yielded results in the form of pressure measurements, froma Prandtl-tube, in the air intake, and footage of smoke tests. As a secondary task the potential of computer simulations during the design process was investigated, which yielded a suggestion on how to set up a complete reasonable computational model of the systems. This also resulted in that the design guidelines included how to use computer simulations for the design process. Finally a few ways to expand this work are presented.
26
Cameron, Cecilia Dianne. "An investigation of squish generated turbulence in. I.C. engines". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25068.
Testo completoAbstract (sommario):
Experiments were performed with a single cylinder C.F.R. engine to provide data for the evaluation of the squish designs. Several reference squish chambers were manufactured for the C.F.R. engine. Flow field data was obtained via hot wire anemometer measurements taken in the cylinder during motored operation of the engine. Pressure data recorded while the engine was operated on natural gas yielded mass burn rate information.
Mass burn rate analysis of cylinder pressure data shows the squish design to have greatest impact on the main combustion period (2% to 85% mass burned). A comparison of the reference squish design in these experiments to the disc chamber shows a 32% reduction in the combustion duration and a 30% increase in peak pressure occurring 5 crank angle degrees earlier. The squish-jet design provided the additional effect of a reduction in the ignition delay time (spark to 2% mass burned). The squish-jet design resulted in a reduction of the ignition delay time by 3 crank angle degrees and in a 4% increase in peak pressure occurring 3 crank angle degrees earlier compared to the reference squish chamber. The total combustion duration was 5% less with the squish-jet design.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
27
Kahraman, Erol Özerdem Barış. "Analysis of a hydrogen fueled internal combustion engine/". [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/enerjimuh/T000321.pdf.
Testo completo
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Lee, Byungho. "Methodology for rapid static and dynamic model-based engine calibration and optimization". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117638435.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xv, 222 p.; also includes graphics. Includes bibliographical references (p. 211-222) Available online via OhioLINK's ETD Center
29
Wiseman, Marc William. "Spark ignition engine combustion process analysis". Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/11131/.
Testo completoAbstract (sommario):
Cylinder pressure analysis is widely used in the experimental investigation of combustion processes within gasoline engines. A pressure record can be processed to reveal detail of charge burning, which is a good indicator of combustion quality. The thesis describes the evaluation of an approximate technique for calculating the mass fraction of the charge that has burnt; a novel approach for determining heat loss to the block; the development of a powerful system for combustion analysis; and the investigation of the correlation between the crank angle location of the 50% mass burnt and minimum timing advance necessary to obtain the maximum engine torque. A detailed examination has been carried out into the uncertainties in the determination of the mass fraction burnt as suggested by Rassweiler and Withrow. A revised procedure has been developed which does not require a priori identification of the combustion end point, and a new approach is suggested to calculate the polytropic indices necessary for the pressure processing. This particular implementation of the analysis is able to identify late burning and misfiring cycles, and then take appropriate steps to ensure their proper analysis. The problems associated with the assumption of uniform pressure; alignment of the pressure changes to the volume changes; pressure sampling rate; clearance volume estimation; and calibrating the acquired pressure to absolute are also evaluated. A novel method is developed to ascertain, directly from the pressure history, the heat loss to the cylinder block. Both experimental and simulated data are used to support the accuracy of the suggested heat loss evaluation, and the sensitivity of the method to its inputs is examined. The conversion of procedures for combustion analysis into a format suitable for undertaking high speed analysis is described. The analysis techniques were implemented so that the engine can be considered to be on-line to the analysis system. The system was entitled Quikburn. This system can process an unlimited number of cycles at a particular running condition, updating the screen every 1.5 seconds. The analysis system has been used to study the potentially beneficial correlation between the location of the 50% mass burnt and MBT. The correlation is examined in detail, and found to be valid except under lean fueling conditions, which is seen to be caused by slow flame initiation. It is suggested that the optimum location of the 50% mass burnt can be used as a reference setting for the ignition timing, and as an indicator of combustion chamber performance. An engine simulation was employed to verify that changes in bum shape account for the small variation seen in the optimum 50% bum locations at different operating conditions of the engine. The bum shape changes also account for the range of optimum locations of the 50% mass burnt encountered in different engines.
30
Page, V. S. "The laser ignition and the in combustion event feedback of internal combustion engines". Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3021746/.
Testo completoAbstract (sommario):
Laser ignition is one of the latest attempts to improve the efficiency and performance of an IC engine. It is slightly unique in that the ignition source is one of the few component of a spark ignited engine that has not been changed in a long time. It is a system that allows a lot of freedom in what can be done with it. Common freedoms are the spatial placement of the spot, splitting the laser into multiple spots, and firing multiple lasers into the engine during a single cycle. It is the last that this thesis is mostly concerned with. Temporal variations are uniquely allowed by lasers over spark plugs, as the optical access allows multiple lasers to be fired into the engine without changing the geometry of the engine. In this thesis, dual pulse laser ignition is investigated, first in a holistic calibration of the timings under a range of engine operating parameters and then selectively with a method of deciding when and if to fire a secondary laser pulse into the engine. It was found that the dual pulse ignition is beneficial to the engine in terms of power efficiency and stability, but only under certain conditions. The magnitude of the benefit is not insignificant, where 1.1% to 2.2% at λ = 1.4 increases in the engine efficiency has been found. The selective firing of the second pulse has also been found to provide benefits and it was found that a potential increase of 3% and 5.5% for λ = 1.35 is possible.
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Bohl, Thomas. "Investigation of biofuelled combustion and their performance optimisation strategies for internal combustion engines". Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3417.
Testo completoAbstract (sommario):
The increasing use of biofuels to replace fossil fuels as well as more stringent emissions regulations for internal combustion engines cause a challenge for the engine manufacturer to build engines that can cope with a large range of fuel properties, but still offer low fuel consumption and very low exhaust emissions. In this work a heavy-duty diesel engine test bed has been built including the fuel and emission analysis equipment suitable for a wide range of biofuels. Also a constant volume spray vessel has been commissioned to optically investigate the macroscopic spray characteristics of different fuels. This vessel was built with the potential investigation of fuel combustion in the future. Four different biofuels, soybean oil methyl ester (SME), palm oil methyl ester (PME), used cooking oil methyl ester (UCOME) and hydrotreated vegetable oil (HVO) in blends of B10, B20, B50 and B100 have been tested, as they are potential candidates to replace mineral diesel in larger scales. The main aim of this project was to investigate the spray and combustion characteristics of various biofuels, their impact on exhaust emissions and performance and the potential optimisation of the control strategy in a heavy-duty Euro V diesel engine. The engine tests revealed that for all biofuels the nitric oxide (NOx) emissions increased compared to mineral diesel (B0), while particulate number (PN), carbon monoxide (CO) and total hydrocarbon (THC) were significantly reduced. The fuel consumption changed according to the heating value and with the three fatty acid methyl esters (FAME) full power was not reached. The macroscopic spray tests showed that lower density fuels, such as HVO, have slower penetration speeds, but wider spray cone angle resulting in better fuel-air mixing conditions. As the engine fuel injection is based on a volumetric injection the heating value and fuel density are mainly influencing the spray characteristics on the engine. In the last part the engine power has been successfully restored for all biofuels and the exhaust emissions have been reduced below the B0 benchmark limits by applying a new engine control strategy showing that the use of neat biofuels can be used on heavy-duty diesel engines without any modifications to the engine hardware and still passing the current emission regulations.
32
Kontarakis, George A. "Homogeneous charge compression ignition in four-stroke internal combustion engines". Thesis, University of Cambridge, 2001. https://www.repository.cam.ac.uk/handle/1810/272293.
Testo completo
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Uczak, de Goes Wellington. "Suspension plasma sprayed thermal barrier coatings for internal combustion engines". Licentiate thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-15198.
Testo completoAbstract (sommario):
The upward trend in internal combustion engine efficiency is likely driven by the depletion of fossil fuels. Since no replacement in sight can deliver energy comparable to the conventional oil, there is a need to use it more rationally and effectively. Thermal barrier coatings have been seen for a long time as a solutionto increase the thermal efficiency of gas turbine engines but suffer from the lackof strong applicability in internal combustion engines. This is due to the different restrictions when comparing the environment on the gas turbines and in internal combustion engines. To overcome this problem and, at the same time, expand the application field of thermal barrier coatings, more efforts need to be devoted.In this work, different top coat materials using various deposition techniques were evaluated and categorized in three different thermal barrier coating (TBC) architectures. The first was the lamellar yttria-stabilized zirconia (YSZ) top coat deposited by atmospheric plasma spray (APS), used as a reference sample. The second architecture was a columnar suspension plasma spray (SPS) TBC with YSZ and gadolinium zirconate (GZO) top coat. The SPS process can produce avariety of microstructures, and they were, for the first time, tested in an internal combustion engine. The third architecture was an SPS top coat, with an additional layer on the top, called a sealing layer of either metallic or ceramic material, both never investigated in a diesel engine application earlier. For the thermophysical properties investigation, a combination of laser flashanalysis (LFA) and modeling with object-oriented finite element (OOF) was employed to understand the properties in all the applications. The performance of the coatings was evaluated in two different ways, by thermal cyclic tests, basedon the TBCs behavior under cyclic thermal loads and by single-cylinder engine experiment. The characterization of the coatings was done by scanning electron microscope (SEM) before and after the thermal cyclic tests.The performance properties were correlated with coatings microstructure and thermophysical properties. It was shown that a columnar TBC produced by SPS had a superior engine efficiency in the single cylinder engine experiment.
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Korir, Patrick Kiprotich. "Experimental Study of Internal Injector Deposits In Internal Combustion Engines Using Renewable Fuels". Thesis, KTH, Materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299199.
Testo completoAbstract (sommario):
The strive to minimize emissions in the automotive industry keeps gaining momentum. Continuous improvement of engine designs and development of more efficient fuel systems in diesel vehicles is a solution to be applauded. More importantly is the growing shift to use of renewable fuels in internal combustion engines. With countries implementing tighter regulations on emissions, and markets have witnessed a rise in the use of biofuels. Subsequently, the fuel quality varies from market to market. Blending of different fuels changes the properties of fuel as solubility of some compounds reduce. Consequently, soft particles which are precipitated in the process have been linked to deposit formation of internal diesel injector deposits (IDIDs). This project aims at investigating IDIDs and possible conditions that enhance their formation in the injector. An injector test rig operating at actual engine pressures (>2000 bars) has been constructed for this purpose. Test fuel for use in the rig is prepared at Scania by introducing soft particles into B10 fuel. Start of the test rig was performed by checking component functionality and pressure test. Due to leakage problem, a redesign of fuel collection cup was done. Evaluation of test fuel was carried to determine the suitability for deposit formation in the injector. Two screening tests were carried to investigate sticky deposit formation using the test fuel. Autoclave test was carried out at temperature of 150 0C over a period of up to four days. Frying pan test was performed to evaluate formation of deposits with increase in temperature between 90 0C to 230 0C. Analysis was carried out using SEM-EDX, GC-MS and FTIR instruments. The test fuel prepared at Scania for replication of deposits in the injector yielded positive results. Sticky deposits formed during the frying pan test evidenced by stretchy and sticky residue on the pan. FTIR analysis showed that the presence of metal carboxylate which is as a result of the metal ion soft particles. Autoclave tests showed formation of brown deposits on the vessel. SEM-EDX analysis of the brown deposits gave great insights on the morphology of the deposit contrasted to the structure of soft particles initially present in the test fuel. Soft particles are small and smeary with a regular shape while the deposits are large, irregular, agglomerated and rough in texture. This is important in understanding the transformation mechanism of soft particles to deposits. A combination of calcium and sodium soft particles in the test fuel showed better ability to form deposits during the autoclave test. GC-MS analysis showed huge decrease in the concentration of soft particles in test fuel after autoclave tests compared to initial test fuel. In conclusion, the test fuel prepared works as expected and thus can be scaled up for running the injector test rig. Additionally, test fuel containing calcium and sodium soft particles have a higher probability to form deposits. Deposits were indeed proven to be metal carboxylates as expected.Strävan efter att minimera utsläppen inom fordonsindustrin fortsätter att ta fart. Kontinuerlig förbättring av motorkonstruktioner och utveckling av effektivare bränslesystem i dieselfordon är en lösning som bör applåderas. Ännu viktigare är den ökande övergången till användning av förnybara bränslen i förbränningsmotorer. Med länder som inför strängare utsläppsregler har marknaderna sett en ökad användning av biobränslen. Därefter varierar bränslekvaliteten från marknad till marknad. Blandning av olika bränslen förändrar bränslets egenskaper när lösligheten hos vissa föreningar minskar. Följaktligen har mjuka partiklar som fälls ut i processen kopplats till avlagringsbildning av interna dieselinjektoravlagringar (IDID). Detta projekt syftar till att undersöka IDID:s och möjliga förhållanden som förbättrar deras bildande i injektorn. En injektortestrigg som arbetar vid faktiska motortryck (>2000-bar) har konstruerats för detta ändamål. Testbränsle för användning i riggen bereds på Scania genom att mjuka partiklar förs in i B10- bränsle. Testriggens start utfördes genom kontroll av komponentens funktionalitet och trycktest. På grund av läckageproblem gjordes en omdesign av bränsleuppsamlingskoppen. En värdering av testbränslet genomfördes för att fastställa lämpligheten för deponeringsbildning i injektorn. Två screeningtester utfördes för att undersöka klibbig avlagringsbildning med hjälp av testbränslet. Autoklavtest utfördes vid en temperatur av 150 C under en period av upp till fyra dagar. Autoklavtest utfördes för att utvärdera bildandet av avlagringar med temperaturökning mellan 90 0C till 230 C. Analysen utfördes med hjälp av SEM-EDX, GC-MS och FTIR instrument. Testbränslet som förbereddes i Scania för replikering av avlagringar i injektorn gav positiva resultat. Klibbiga avlagringar som bildas under stekpannans test framgår av stretchiga och klibbiga rester på pannan. FTIR-analys visade att förekomsten av metallkarboxylat som är ett resultat av metalljonens mjuka partiklar. Autoklavtester visade bildandet av bruna avlagringar på fartyget. SEM-EDX-analysen av de bruna avlagringarna gav stora insikter om depositionens morfologi i motsats till strukturen hos mjuka partiklar som ursprungligen fanns i testbränslet. Mjuka partiklar är små och utsmetade med en regelbunden form medan avlagringarna är stora, oregelbundna, agglomererade och grova i konsistensen. Detta är viktigt för att förstå omvandlingsmekanismen för mjuka partiklar till avlagringar. En kombination av kalcium- och natriummjuka partiklar i testbränslet visade bättre förmåga att bilda avlagringar under autoklavtestet. GC-MS-analysen visade en enorm minskning av koncentrationen av mjuka partiklar i testbränsle efter autoklavtester jämfört med det ursprungliga testbränslet. Sammanfattningsvis fungerar testbränslet som förväntat och kan därför skalas upp för att driva injektortestriggen. Dessutom har testbränsle som innehåller mjuka kalcium- och natrium partiklar större sannolikhet att bilda avlagringar. Avlagringarna visade sig faktiskt vara metallkarboxylater som förväntat.
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Lorimer, Alexander P. C. K. S. Carleton University Dissertation Engineering Mechanical. "An experimental study of co-axial tailpipe mufflers for internal combustion engines". Ottawa, 1992.
Cerca il testo completo
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Weiland, Nathan T. "Feasibility Analysis of an Open Cycle Thermoacoustic Engine with Internal Pulse Combustion". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4789.
Testo completoAbstract (sommario):
Thermoacoustic engines convert thermal energy into acoustic energy with few or no moving parts, thus they require little maintenance, are highly reliable, and are inexpensive to produce. These traits make them attractive for applications in remote or portable power generation, where a linear alternator converts the acoustic power into electric power. Their primary application, however, is in driving thermoacoustic refrigerators, which use acoustic power to provide cooling at potentially cryogenic temperatures, also without moving parts.
This dissertation examines the feasibility of a new type of thermoacoustic engine, where mean flow and an internal pulse combustion process replace the hot heat exchanger in a traditional closed cycle thermoacoustic engine, thereby eliminating the heat exchangers cost, inefficiency, and thermal expansion stresses. The theory developed in this work reveals that a large temperature difference must exist between the hot face of the regenerator and the hot combustion products flowing into it, and that much of the convective thermal energy input from the combustion process is converted into conductive and thermoacoustic losses in the regenerator. The development of the Thermoacoustic Pulse Combustion Engine, as described in this study, is designed to recover most of this lost thermal energy by routing the inlet pipes through the regenerator to preheat the combustion reactants. Further, the developed theory shows that the pulse combustion process has the potential to add up to 7% to the engines acoustic power output for an acoustic pressure ratio of 10%, with linearly increasing contributions for increasing acoustic pressure ratios.
Computational modeling and optimization of the Thermoacoustic Pulse Combustion Engine yield thermal efficiencies of about 20% for atmospheric mean operating pressures, though higher mean engine pressures increase this efficiency considerably by increasing the acoustic power density relative to the thermal losses. However, permissible mean engine pressures are limited by the need to avoid fouling the regenerator with condensation of water vapor out of the cold combustion products. Despite lower acoustic power densities, the Thermoacoustic Pulse Combustion Engine is shown to be well suited to portable refrigeration and power generation applications, due to its reasonable efficiency and inherent simplicity and compactness.
37
Zhao, Junfeng. "A Fully Flexible Valve Actuation System for internal combustion engines". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12919.
Testo completoAbstract (sommario):
Air pollution, global warming, and rising gasoline prices have lead governments,
environmental organizations, and consumers to pressure the automotive
industry to improve the fuel efficiency of cars.
Since alternative fuels such as hydrogen are still quite far from being
commercially viable, improving the existing internal combustion engine is
still an important priority. Traditional internal combustion engines use a
camshaft to control valve timing. Since the camshaft is rigidly linked to
the crankshaft, engineers can optimize the camshaft only for one particular
speed torque combination. All other engine operating points will suffer from
a suboptimal compromise of torque output, fuel efficiency, and emissions. In
an engine with a camless valve actuation system, valve events are controlled
independently of crankshaft rotation. As a result, fuel consumption and
emissions may be reduced by 15%~20% and torque output is enhanced in
a wide range of engine speeds.
The Fully Flexible Valve Actuation (FFVA) system is our approach to
construct a camless valve actuation system. Within the limits of the dynamic
bandwidth of the system, it allows for fully user definable valve trajectories
that can be adapted to any need of the combustion process. The system
is able to achieve 8mm valve lift in 3.4ms, which is suitable for an engine
operating at 6000RPM. The valve seating velocity is similar to conventional
valve trains that achieve 0.2m/s at high engine speeds and 0.05m/s at engine
idle conditions. Finally, the energy consumption measured in an experimental
test bed matches the friction losses of conventional valve trains and it
can further be improved by using an optimized motor.
This thesis describes the progress that has been made towards designing
this technology. A design methodology is derived and important operation
features of the mechanism are explained. Modeling and simulation results
show significant advantages of the FFVA over previously designed electromagnetic
engine valve drives.
38
Panting, Julian Ross. "The modelling and optimisation of high performance internal combustion engines". Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/11854.
Testo completo
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Hussin, Ahmed Mohamed Taher Alaa Eldein. "New and renewable energy: renewable fuels in internal combustion engines". Thesis, University of Leeds, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590482.
Testo completoAbstract (sommario):
At the moment the main impetus to move towards alternative fuels produced from renewable resources is legislation and market forces, which push the automotive industry to limit pollutant emissions. One way of reducing these hannful emissions is to replace the conventional fossil fuel totally with syngas or partially with alcohols and/or their ethers. The bending of alcohols to gasoline has been attempted since the mid of 1970's and recently it is in practice in some countries. Interestingly, alcohols are more competitive among the other alternatives such as syngas because they are compatible with existing fuelling distribution infrastructure and are easily stored in a vehicle. However, this blending may change the burning rate which consequently changes the level of cyclic variations. Cycle-to-cycle variability is the main cause of reduction in power output and efficiency and deterioration in the vehicle driveabiIity. Therefore, the main objective of this study was to investigate the impact of employing renewable fuels in spark ignition engine on the cycle-to-cycle variations. The employed fuels involved synthetic gas mixture of 2H2+CO, blends of Ethyl Tert Butyl Ether (ETBE) with primary reference fuel (PRF), and a commercial gasoline fuel (EOS) containing 5 % by volume of ethanol. In the first stage of this work, Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) techniques were employed to characterise the in-cylinder turbulent flow at different engine speed during motoring cycles. In the main stage of the current study, PlY and LDV was also employed to monitor the in-cylinder flow during firing experiments simultaneously with natural light video photography for recording the flame propagation and pressure recordings methods. Results verified that, there was a slight increase in the cyclic variability of the indicated mean effective pressure with increasing the percentage of ETBE in the mixture. The cyclic variability has decreased when using E05 in comparison with PRF or its blends with ETBE. On the other hand, it was possible to run the engine at an equivalence ratio of 0.3 with 2H2+CO due to the extended flammability limit of hydrogen containing mixtures. Spatial and temporal analysis of flow field parameters for individual cycles was adopted in the current study. The analysis showed that there is a high degree of connection between early flame kernel development, RMS turbulent velocity and global burning rate of a cycle, such that a cycle that start fast will remain fast throughout the cycle in most cases.
40
Leathard, Matthew James. "Computational modelling of coolant heat transfer in internal combustion engines". Thesis, University of Bath, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248102.
Testo completo
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Piaszyk, Jakub. "Animal fat (tallow) as fuel for stationary internal combustion engines". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/4135/.
Testo completoAbstract (sommario):
The main aim of this thesis is to verify the suitability of waste animal fat, obtained from animal by-products in a process called rendering, as a fuel for internal combustion engines. This work is an attempt to provide guidance and minimal requirements for animal fat to be utilised as fuel. The properties of tallow were monitored on a weekly basis throughout a period of one year. Some properties, namely acidity, showed significant variability. Possible reasons causing variable and high acidity are given together with a proposal for an acidity removal method. The available laboratory facilities enabled the verification of changes in fat's viscosity, density, surface tension and lubricity in a range of temperatures. The impact of storage temperature on deterioration in tallow quality was investigated over a period of one month. The available emission control systems have been reviewed and a solution choice has been made, based on legal and economic criteria. A summary of two thousand hours operation of the 800 kW generating set using neat fat is provided. The renewable electricity generation subsidising system in the United Kingdom has been reviewed. A basic feasibility study for the installed generating set was prepared and the highest tallow price at which electricity generation is profitable was determined.
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Taylor, Oliver. "Improving the performance of internal combustion engines through lubricant engineering". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:4db8f32e-8260-4cff-ad57-08bfa0b9568e.
Testo completoAbstract (sommario):
Low friction lubricant development provides a worthwhile contribution to vehicle CO2 emission reduction. Conventional low friction lubricant development focuses on empirical processes using out dated engine technology and old test methods. This strategy is inefficient and restricts the lubricant's potential. A new method proposed in the present research combines tribological simulations with rig, engine and vehicle tests. This approach provides insights undocumented until now. The contribution to CO2 emission reduction from individual engine components on vehicle drive cycles that include warm-up is predicted using lubricants down to the new SAE 8 viscosity grade. A bearing model is used to design the lubricant's non Newtonian characteristics to achieve friction reduction. An isoviscous lubricant with a viscosity of 4.6 cSt is shown to achieve the minimum friction in the bearing. The research shows that by starting with lubricants having kinematic viscosities higher than this value, it is possible to improve lubricant performance by lowering viscosity index (VI), introducing shear thinning, or reducing the density and pressure viscosity coefficient. Conversely, for lubricants with lower starting viscosities it is shown that higher VI values, more shear-stable lubricants and higher densities and pressure viscosity coefficients are required. The model predicts that high oil film pressures occur in the bearing and cause significant local lubricant viscosity increase (300%), indicating that the lubricant's pressure viscosity behaviour is important here, despite the contact being conformal. Simulation and motored engine testing establishes lubricant behaviour in the piston-to-bore conjunction. This analysis identifies a poor correlation between measured and predicted values at low engine speeds. A rig-on-liner tribometer shows that this error is attributable to a deficiency in the simulation's characterisation of boundary regime friction. An oil pump test determines how a modern variable displacement oil pump (and its control system) responds to lowering viscosity. The hypothesis that low viscosity lubricants cause the parasitic load from this component to increase is disproven using this component-level rig test. Chassis dynamometer testing compares the CO2 reduction performance of lubricant thermal management systems to the values achieved by reducing the viscosity grade. CO2 reductions of between 0.4% and 1.0% are identified using a cold-start new European drive cycle (NEDC) with a 5W-30 preheated to 60°C and 90°C respectively. Reductions in CO2 emissions between 0.4% and 1.2% are found on the NEDC by lowering the oil fill volume from 5.1 L to 2.1 L. For the unmodified case, a 3.7% reduction in CO2 emissions is reported by reducing the viscosity grade from a 5W 30 to an SAE 8 in the NEDC. The performance of a novel external oil reservoir is simulated to understand its ability to retain oil temperature during the vehicle cool-down procedure. An oil temperature of 65°C at the end of the soak period (following a prior test where the oil was assumed to reach 90°C) is predicted by installing insulation to the reservoir and indicates that a viable method to achieve the CO2 benefits identified through lubricant preheating tests exists. A full vehicle model combines the outputs from each of these sub-models to predict lubricant performance on the NEDC the new World-wide harmonized light duty test cycle (WLTC). This new approach provides a tool that enables next generation low friction lubricants to be developed. The model predicts that an SAE 8 lubricant can reduce CO2 emissions by 2.8% on the NEDC and 1.9% on the WLTC compared to a 5W-30. A theoretical experiment, where all lubricant related friction was deleted from the simulation, predicts that lubricant-related CO2 emissions are 8.7% on the NEDC and reduce to 6.3% on the WLTC. These results indicate that the planned adoption of the WLTC in September 2017 reduces the potential contribution to CO2 emission reduction from lubricants by 28%.
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Batista, João Carlos dos Santos. "Development of variable displacement oil pump for internal combustion engines". Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/15797.
Testo completoAbstract (sommario):
Mestrado em Engenharia MecânicaIn the last years the need to develop more environmentally friendly and efficient cars as led to the development of several technologies to improve the performance of internal combustion engines, a large part of the innovations are focused in the auxiliary systems of the engine, including, the oil pump, this is an element of great importance in the dynamics of the engine as well a considerable energy consumer. Most solutions for oil pumps to this day are fixed displacement, for medium and high speeds, the pump flow rate is higher than the needs of the engine, this excess flow leads to the need for recirculation of the fluid which represents a waste of energy. Recently, technological advances in this area have led to the creation of variable displacement oil pumps, these have become a 'must have' due to the numerous advantages they bring, although the working principle of vane or piston pumps is relatively well known, the application of this technology for the automotive industry is new and brings new challenges. The focus of this dissertation is to develop a new concept of variable displacement system for automotive oil pumps. The main objective is to obtain a concept that is totally adaptable to existing solutions on the market (engines), both dimensionally as in performance specifications, having at the same time an innovative mechanical system for obtaining variable displacement. The developed design is a vane pump with variable displacement going in line with existing commercial solutions, however, the variation of the eccentricity commonly used to provide an variable displacement delivery is not used, the variable displacement is achieved without varying the eccentricity of the system but with a variation of the length of the pumping chamber. The principle of operation of the pump is different to existing solutions while maintaining the ability to integrate standard parts such as control valves and mechanical safety valves, the pump is compatible with commercial solutions in terms of interfaces for connection between engine systems and pump. A concept prototype of the product was obtained in order to better evaluate the validity of the concept. The developed concept represents an innovation in oil pumps design, being unique in its mechanical system for variable displacement delivery.
Nos últimos anos, a necessidade de desenvolver carros amigos do ambiente e mais eficientes levou ao desenvolvimento de várias tecnologias para melhorar o desempenho de motores de combustão interna, uma grande parte das inovações são focadas nos sistemas auxiliares do motor, incluindo a bomba de óleo, sendo este um elemento de grande importância para a dinâmica do motor, bem como um considerável consumidor de energia. Maioria das soluções até aos dias de hoje para bombas de óleo são de caudal fixo, para velocidades médias e altas, o fluxo da bomba é superior às necessidades do motor, este excesso de fluxo leva à necessidade de recirculação do fluido que o que representa um desperdício de energia. Recentemente, os avanços tecnológicos nesta área têm levado à criação de bombas de óleo de caudal ajustável, estas têm-se tornado um 'tem de ter’ devido às inúmeras vantagens que trazem, embora o princípio de funcionamento das bombas com palhetas ou pistões sejam relativamente bem conhecidos, a aplicação desta tecnologia para a indústria automóvel é recente e traz novos desafios. O foco desta dissertação está no desenvolvimento de um novo conceito de bomba de óleo de caudal ajustável para o sector automóvel. O principal objectivo é a obtenção de um conceito que, sendo totalmente adaptável às soluções existentes no mercado (motores), tanto dimensionalmente como nas especificações de desempenho, possua um sistema mecânico inovador para a obtenção de caudal ajustável. A bomba desenvolvida é um sistema de palhetas com caudal ajustável indo em linha com as soluções comercias existentes, no entanto, a variação da excentricidade habitualmente utilizada a fim de proporcionar um caudal ajustável é anulada, o débito variável é obtido sem variação da excentricidade do sistema, mas com uma variação do comprimento da camara de bombagem. O princípio de funcionamento é diferenciado às soluções, actuais mantendo no entanto a capacidade de integrar peças padrão como válvulas de controlo mecânico e válvulas de segurança, a bomba é compatível com as soluções comerciais em termos de interfaces para ligação entre os sistemas de motor e bomba. Foi desenvolvido um protótipo conceptual do produto de modo a melhor avaliar a validade do conceito. O conceito desenvolvido representa uma inovação em design de bombas de óleo, sendo única no seu sistema mecânico para entrega de caudal ajustável.
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Lakkis, Sari. "New Gas Sensor for Exhaust Emissions of Internal Combustion Engines". Thesis, Versailles-St Quentin en Yvelines, 2014. http://www.theses.fr/2014VERS0064/document.
Testo completoAbstract (sommario):
L’analyse des gaz d’échappement des moteurs à combustion interne a été traditionnellement réalisée en laboratoires en utilisant des analyseurs de gaz en vrac avec des équipements coûteux. Afin de créer un système capable de réaliser le travail de ces analyseurs, un capteur pouvant détecter plusieurs gaz simultanément est indispensable pour en mesurer la concentration. En effet, utiliser un capteur pour chaque gaz est couteux et peut amener à des procédures complexes d’analyse en raison des différentes technologies utilisées. De plus, l’utilisation de multiples capteurs donne lieu à une perte de ressources financières et humaines. Pour pallier ce problème, une approche alternative proposée dans cette thèse consiste à utiliser un seul capteur pour l’analyse simultanée des différents gaz. Cette approche contribue à réduire la complexité des analyses, la taille et la collecte de données des mesures de gaz mentionnés précédemment. Elle permet également la baisse du coût de l’ensemble du système des mesures.Cette thèse présente la conception, la méthodologie et le développement d’une nouvelle approche pour la mesure de la concentration de gaz utilisant le traitement d’images numériques à travers la modélisation du mélange des couleurs d’émission de lumière dans le tube de décharge de gaz. L’application du modèle inverse permet d’obtenir le pourcentage de chaque gaz dans un mélange contenant jusqu'à quatre gaz connaissant la couleur d’émission du mélange et la couleur d’émission de chaque gaz. Nous discutons aussi le potentiel de certaines méthodes quant à leurs propriétés de miniaturisation et leurs limites. Une comparaison entre les différents capteurs miniaturisés est réalisée en termes suivant la sensibilité, la sélectivité, le coût et d’autres conditions. Pour atteindre les objectifs de recherche, les problèmes techniques rencontrés tels que la modélisation de mélange des couleurs, l’étalonnage de capteurs pour l’acquisition d’images, et le traitement des erreurs de mesures ont été identifiés et des solutions ont été proposéesGases represent one of the most important key measurands in many industrial and domestic activities. The need to detect single gas or a group of gases at the same time varies from one application to another. One of the most important applications of gas sensing is in the concentration measurement of exhaust emissions in internal combustion engines. The variety of gases emitted by these engines and the necessity for a precise measurement of their concentrations are the major incentives for researchers to develop gas sensors that are not only limited to a certain type of gases but to a variety of gases. The most interest gases include CO, NO, NO2, NH4, SO2, CO2, CH4 and other hydrocarbons. These gases can be harmful to human health if present beyond a certain concentration. The analysis of exhaust emissions of internal combustion engines has traditionally been achieved in laboratories using bulk gas analyzers and costly equipments. In order to create a system which can do the work of these analyzers, a sensor that can measure the concentration of multiple gases at the same time is needed. Instead of using a sensor for each gas which is costly and introduce another complexity to the analysis procedure due to the different technologies that are used in the detection of different types of gases. This directly translates into loss of financial and human resources that could otherwise be productively used. In an effort to remedy this situation, this dissertation proposes an alternate approach that uses one sensor to analyze multiple gases simultaneously. This has a significant potential in reducing the aforementioned complexity, size and data collection tasks, and at the same time can lower the cost of the overall system.This dissertation presents the design, methodology, and development of a new method for gas concentration measurement using digital image processing through modeling the color mixing of light emissions in gas discharge tube. The application of the inverse model allows us to get the percentages of each gas in a mixture of up to four gases knowing already the color of emission of the whole mixture and the color of emission of each gas alone. It also discusses the miniaturization potential of some of the methods that are promising in the ability of their miniaturization but suffer from different problems. A comparison is also done among the miniaturized sensors in terms of different parameters like sensitivity, selectivity, cost and other terms. In achieving the research objectives, major technical challenges such as color mixing modeling, imaging sensor calibration, and measurements’ error handling have been successfully identified and addressed
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Mobley, Christopher G. "Dynamic timing of internal combustion engines using non-intrusive sensors". Thesis, University of Bath, 2001. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426181.
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Green, Jeremy James. "Taguchi methods in internal combustion engine optimisation". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52475.
Testo completoAbstract (sommario):
Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: Statistical experimental design techniques are powerful tools that are often approached with suspicion and apprehension by experimenters. The trend is to avoid any statistically structured and designed experimentation program, and to rather use the traditional method of following ones "gut feel". This approach, more often than not, will supply a satisfactory solution, but there is so much more information availablefor the same amount of effort. This thesis strives to outline the method and application of the Taguchi methodology of experimental design. The Taguchi method is a practical, statistical experimental design technique that does not rely on the designer's knowledge of the complex statistics typicallyneeded to design experimental programs, a fact that tends to exclude design of experiments from the averageengineers' toolbox. The essence of the statistical design of experiments is this: The traditional method of varying one variable at a time and investigating its effect on an output is no longer sufficient. Instead all the input variables are varied at the same time in a structured manner. The output trends resulting from each input variable are then statisticallyextracted from the data in the midst of the variation. Taguchi method achieves this by designing experiments where every level of every input variable occurs an equal number of times with every level of every other input variable. The experimental designs are represented in orthogonal arrays that are chosen and populated by the experimenter by following a simple procedure. Four case studies are worked through in this text and, where possible, compared to the "traditional" approach to the same problem. The case studies show the additional information and time savings availablewith the Taguchi method, as well as clearlyindicating the importance of using a stable system on which to do the experiments. The Taguchi method generated more information in fewer experiments than the traditional approaches as well as allowing analysis of problems too complex to analysewithout a statisticaldesign of the experimentation procedure.
AFRIKAANSE OPSOMMING: Statistiese eksperimentele ontwerptegnieke is besonder kragtige instrumente wat baie keer met agterdog deur ekspermenteerders beheen word. Die neiging is om enige statistiese gestruktureerde and ontwerpte eksperimentele program te vermy, en om liewer die tradisionele metode, wat op 'n mens se intuïsie staatmaak, te gebruik. Hierdie benadering sal baie keer 'n bevredigende oplossing gee, maar daar is veel meer inligting vir dieselfde hoeveelheid inspanning verkrygbaar, wanneer die Taguchimetode gebruik word. Hierdie tesis strewe om die metode en toepassing van die Taguchimetodologie van eksperimentele ontwerp voor te lê. Die Taguchimetode is 'n praktiese statistiese eksperimentele ontwerptegniek .wat nie op die ontwerper se kennis van komplekse statistiek om eksperimentele programme te ontwerp berus nie. Hierdie komplekse statistiek neig ook om eksperimentele ontwerp van die gemiddelde ingenieursvaardigehede uit te sluit. Die kern van statistiese eksperimentele ontwerp is die volgende: Die tradisionele metode van een veranderlike op 'n slag te varieer om die effek op die uitset te ondersoek, is onvoldoende. In plaas daarvan, word al die insetveranderlikes gelyktydig gevarieer in 'n gestruktureered manier. Die neigings van elke veranderlike is dan statisties ontleed van die data ten midde van die variasie van al die ander veranderlikes. Die Taguchimetode bereik die ontwerpte eksperimente deur elke vlak van elke insetveranderlik in 'n gelyke aantal keer met elke vlak van elke ander insetveranderlike te varieer. Hierdie is verteenwoordig deur ortogenale reekse wat gekies en gevul is deur 'n eenvoudige wisselpatroon te volg. Vier gevallestudies is deurgewerk en, waar moontlik, vergelyk met die tradisonele siening van dieselfde probleem. Die gevallestudies wys hoe toereikbaar die additionele inligting in die Taguchimethode toepassings is. Hulle beklemtoon ook die belangrikheid van 'n stabiele sisteem waarop die eksperimente berus. Die Taguchimetode het meer inligting verskaf met minder eksperimente as die tradisionele toenaderings, en ook toegelaat dat die analise van probleme, te kompleks om te analiseer sonder om 'n statistiese ontwerp van eksperimentele prosedure te volg, opgelos kon word.
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Faber, Peggy A. "A digital indicator diagram generation system for the Ricardo E6 engine /". Online version of thesis, 1987. http://hdl.handle.net/1850/10291.
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Ochel, Ralf. "NOx̳ reduction for antural gas engines with increased ignition energy and plasma jet ignitors /". This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06122009-063015/.
Testo completo
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Leroy, Thomas. "Cylinder filing control of variable-valve-actuation equipped internal combustion engines". Paris, ENMP, 2010. https://theses.hal.science/tel-00506471.
Testo completoAbstract (sommario):
Nous étudions la production de couple et de polluants de moteurs à combustion interne à distribution variable d'un type fréquemment répandu dans l'industrie automobile (moteurs Diesel ou essence). Les systèmes de distribution variable (VVA pour Variable Valve Actuation) ont été introduits dans les moteurs pour optimiser l'efficacité du fonctionnement global sur des plages très larges de points de fonctionnement, considérés à l'équilibre. A tout instant, les résultats de la combustion dépendent du remplissage en air/gaz brûlés du cylindre, qui lui même dépend de la position des actionneurs VVA et des conditions dans le collecteur d'admission. Ces deux sous-systèmes ont des temps de réponse différents, ce qui conduit, pendant les transitoires, à des pertes d'efficacit ́e du moteur. Dans cette thèse, nous proposons une solution a ce problème, qui prend la forme de boucle de coordination entre les sous-systèmes de contrôle de bas-niveau. Cette coordination s'effectue par l'intermédiaire d'un modèle de remplissage développé dans ce manuscrit. Des résultats expérimentaux établissent qu'il est possible d'améliorer la production de couple et de réduire les polluantsThe production of torque and pollutants of Variable Valve Actuation equipped internal combustion engines found in the automotive industry (both Diesel and gasoline engines) is studied. Variable Valve Actuation (VVA) is a technology which has been introduced to optimize engine efficiency at steady-states covering a wide range of operating conditions. In more details, the outcome of the internal combustion engine (torque and pollutant) depends on the cylinder filling at each stroke which, itself, depends on the VVA positions and the engine intake manifold conditions. These two subsystems have inconsistent response times which results in efficiency losses during transient operations. In this manuscript, a remedy for this issue which takes the form of coordination loops of low-level controllers is proposed. This coordination uses a cylinder filling model, designed in the thesis. Experimental results prove that torque production and pollutant emissions can be improved
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IEMMOLO, DANIELE. "Alternative fuels and combustion modes to lower pollutant emissions from conventional internal combustion engines". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2724575.
Testo completo