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1
Joo, Won-Gu. « Intake/engine flowfield coupling in turbofan engines ». Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319865.
Texte intégral
2
Boswell, Michael John. « Gas engines for domestic engine-driven heat pumps ». Thesis, Oxford Brookes University, 1992. http://radar.brookes.ac.uk/radar/items/37f7ed18-4b86-6ab3-8ba6-1c27947fb1ce/1.
Texte intégralRésumé :
An experimental and theoretical investigation has been undertaken into the performance of a small prototype, water-cooled, gas-fuelled engine designed for use as a domestic heat pump prime mover. In light of the application, fuel type and capacity, both experimental and theoretical study of similar engines is at best poorly documented in the literature. A comprehensive engine test facility has been set up, incorporating extensive calorimetry, a separate lubrication system, emissions monitoring and high speed data acquisition for in-cylinder pressure measurement and analysis. Two new experimental cylinder heads have been designed together with new induction and exhaust systems, both to improve performance and to enable further investigation of the combustion process. A preliminary parametric study of the combustion process established that the thermal efficiency and emission levels are strongly dependent on operational and design variables and that a lean, fast-burning combustion process in a slow speed engine coupled with careful control of other operating variables had the potential for improving efficiency, reducing emissions, and lowering frictional losses and noise levels with enhanced durability. Accordingly, new information has been obtained relating to rates of heat release, energy flows and emission levels over a wide range of design and operating conditions with utility for and consistent with an envelope of conditions appropriate to such a lean burn strategy. Modelling techniques have been developed and used as diagnostic tools in conjunction with the experimental data to investigate the influence of operating and design variables on rates of heat release and energy flows. The models have been validated using the experimental data over a wide range of operating conditions and incorporated into a thermodynamic engine model for use as a sub-model in an overall heat pump model. The experimental and theoretical programme has provided a valuable insight into the lean burn strategy and realised a considerable improvement in the performance of the prototype engine. The theoretical study benefits from a new approach to small gas engine design and development.
3
Calnan, Peter John Courtney Benedict. « Analysis of new engine cycles for spark ignition engines ». Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389985.
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4
Blaauw, Pieter. « Search engine poisoning and its prevalence in modern search engines ». Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002037.
Texte intégralRésumé :
The prevalence of Search Engine Poisoning in trending topics and popular search terms on the web within search engines is investigated. Search Engine Poisoning is the act of manipulating search engines in order to display search results from websites infected with malware. Research done between February and August 2012, using both manual and automated techniques, shows us how easily the criminal element manages to insert malicious content into web pages related to popular search terms within search engines. In order to provide the reader with a clear overview and understanding of the motives and the methods of the operators of Search Engine Poisoning campaigns, an in-depth review of automated and semi-automated web exploit kits is done, as well as looking into the motives for running these campaigns. Three high profile case studies are examined, and the various Search Engine Poisoning campaigns associated with these case studies are discussed in detail to the reader. From February to August 2012, data was collected from the top trending topics on Google’s search engine along with the top listed sites related to these topics, and then passed through various automated tools to discover if these results have been infiltrated by the operators of Search Engine Poisoning campaings, and the results of these automated scans are then discussed in detail. During the research period, manual searching for Search Engine Poisoning campaigns was also done, using high profile news events and popular search terms. These results are analysed in detail to determine the methods of attack, the purpose of the attack and the parties behind it
5
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.
Texte intégralRésumé :
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
6
Sanders, Matthew Graham. « Analytical applications of the peroxyoxalate chemiluminescence reaction ». Thesis, University of Plymouth, 1999. http://hdl.handle.net/10026.1/1832.
Texte intégralRésumé :
The overall objectives of this thesis were to investigate the potential of the peroxyoxalate chemiluminescence (POOL) reaction for the quantitative detection of target analytes in non-aqueous matrices and to compare quantitative performance with fluorescence detection. The target analytes investigated were polycyclic aromatic hydrocarbons (PAHs) and aliphatic amines. These were selected as an important class of compounds in engine exhaust emissions and a detergent additive in diesel fuel respectively. Chapter one outlines the challenges of analysing petroleum products and engine exhaust emissions and discusses the potential of luminescence techniques, particularly chemiluminescence (CL), for the quantification of trace components. The chapter also reviews the technique of flow injection (FT) as a means of sample delivery for CL detection and as a potential technique for field deployment. Liquid chromatography techniques are described as a means of separation of complex matrices, e.g. fuels and engine exhaust particulates, in the laboratory prior to CL detection. The luminescence properties of several PAHs were investigated in Chapter Two. Optimum excitation and emission wavelengths for eleven PAHs in four different solvents were determined using a batch fluorescence technique. A FI approach was used to determine PAH concentrations using fluorescence and POCL detection. Two aryl oxalates; bis(2,4-dinitophenyl)oxalate and bis(2,4,6-trichlorophenyl)oxalate were compared for their suitability for PAH determinations and an investigation of the key variables (e.g. concentration of aryl oxalate and hydrogen peroxide, mobile phase composition and pH) affecting POCL was performed. Recommendations for the optimum conditions for the determination of PAHs by POCL detection were determined, A comparison between a photodiode based detection device and a low power (12V) photomultiplier tube was also described. In Chapter Three the procedure of using POCL detection as a post column liquid chromatography (LC) detector for PAHs has been considered. The performance of the POCL detection system was compared with wavelength programmed fluorescence. Both reversed and normal phase LC was investigated and the suitability of POCL detection with each approach was discussed. Additionally the procedure for the LC separation and analysis of SRM 1649 (Urban Dust/Organics) and SRM 1650 (Diesel Particulate Matter) was described. The relative performance of fluorescence and CL detection are discussed. Chapter four describes the principles of multivariate calibration of spectrophotometric data, and three commonly applied techniques (PCR, PLSI and PLS2). Fluorescence data was obtained for synthetic mixtures of PAHs containing two, three, four and five components. A procedure whereby individual spectra were 'glued' together before undergoing data analysis has been developed and the results obtained discussed. POCL emission spectra for five PAHs were acquired using a two-dimensional charge coupled device (CCD). The sensitivity of the CCD system toward POCL detection of PAHs and a multivariate investigation using benzo[a]pyrene and benzo[k]fluoranthene has been described. The potential of the fluorescence and CL approaches used has been discussed. Chapter five describes the aryl oxalate sulphorhodamine-101 CL reaction and its application to the determination of amines. A FI optimisation of the reaction parameters is presented together with some quantitative data for the detection of a homologous series of amines and dodecylamine (a commonly added detergent compound in diesel fuels). The application of the technique toward the detection of dodecylamine in a diesel fuel matrix and the potential as a field deployable technique was also considered.
7
Kapadia, Bhavin Kanaiyalal. « Development Of A Single Cylinder SI Engine For 100% Biogas Operation ». Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/283.
Texte intégralRésumé :
This work concerns a systematic study of IC engine operation with 100% biogas as fuel (as opposed to the dual-fuel mode) with particular emphasis on operational issues and the quest for high efficiency strategies. As a first step, a commercially available 1.2 kW genset engine is modified for biogas operation. The conventional premixing of air and biogas is compared with a new manifold injection strategy. The effect of biogas composition on engine performance is also studied.
Results from the genset engine study indicate a very low overall efficiency of the system. This is mainly due to the very low compression ratio (4.5) of the engine. To gain further insight into factors that contribute to this low efficiency, thermodynamic engine simulations are conducted. Reasonable agreement with experiments is obtained after incorporating estimated combustion durations. Subsequently, the model is used as a tool to predict effect of different parameters such as compression ratio, spark timing and combustion durations on engine performance and efficiency. Simulations show that significant improvement in performance can be obtained at high compression ratios.
As a step towards developing a more efficient system and based on insight obtained from simulations, a high compression ratio (9.2) engine is selected. This engine is coupled to a 3 kW alternator and operated on 100% biogas. Both strategies, i.e., premixing and manifold injection are implemented. The results show very high overall (chemical to electrical) efficiencies with a maximum value of 22% at 1.4 kW with the manifold injection strategy. The new manifold injection strategy proposed here is found to be clearly superior to the conventional premixing method. The main reasons are the higher volumetric efficiency (25% higher than that for the premixing mode of supply) and overall lean operation of the engine across the entire load range. Predictions show excellent agreement with measurements, enabling the model to be used as a tool for further study. Simulations suggest that a higher compression ratio (up to 13) and appropriate spark advance can lead to higher engine power output and efficiency.
8
SHOJAEE, Maryam. « Modelling for the thermal degradation of engine oil in diesel engines ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175385.
Texte intégralRésumé :
Thermal oil oxidation is an important reason for the engine oil degradation in trucks. Having a comprehensive model that includes all the influential factors while it is feasible for being implemented in the ECUs, was aimed for this work. Therefore, the chemical investigating of the problem leaded to propose a first kinetic model and its thermal analysis caused modelling the oil thermal behaviour. The latter was developed for four compartments: Bearings, turbocharger, piston cooling and oil sump in the oil path through the lubrication system, because the highest oil temperature happens due to friction, combustion of fuels and exhaust gas transportation. Independency from the design parameters of the compartments and simplicity of models for the ECU implementation caused to investigate two various modelling hybrid approach: physical modelling and control theory approach. The first one was done for the bearings and piston cooling, and showed a high level of complexity leading to switch to the second approach. The latter was applied for all compartments while it satisfied requested requirements. To adjust and evaluate the models, an experimental campaign was devoted to acquiring the needed parameters with consideration of the project budget. Also using the previous simulation and experimental efforts at the company provided a possibility to develop flow rate sub-models used in the thermal modelling. The proposed model for all compartments, well predicted the oil thermal behaviour for both stationary and dynamic operating conditions. A comparison between the experimental data for the oil in the oil sump and turbo charger was done to show the reliability of the related models in both stationary and transient statuses. For the bearings, the simulation data for stationary condition were applied as a reference. The modelled oil temperature after piston cooling was compared to a set of experimental data that presented the probable temperature in some conditions close to stationary operating points.
9
Duszynski, Marek. « Measurement of lubricant film thickness in reciprocating engines ». Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8268.
Texte intégral
10
Kalinov, Pavel. « Intelligent Web Exploration ». Thesis, Griffith University, 2012. http://hdl.handle.net/10072/365635.
Texte intégralRésumé :
The hyperlinked part of the internet known as "the Web" arose without much planning for a future of millions of publishers and countless pieces of online content. It has no in-built mechanism to find anything, so tools external to it were introduced: initially web directories and then search engines. Search engines are based on machine learning and have been extremely successful. However, they have some inherent limitations and cannot, by design, address some needs: they serve the "information locating" need only and not "information discovery". Search engine users have learned to accept them and in many cases do not realise how their search has been limited by shortcomings of the model. Before the advent of the search engine, web directories were the only information-finding tool on the web. They were manually built and could not compete economically with the effciency of search engines. This lead to their virtual extinction, with the effect that the "information discovery" need of users is no longer served by any major information provider. Furthermore, none of the dominant information-finding models account for the person of the user in any meaningful way controllable by (or even visible to) the user. This work proposes a method to combine a search engine, a web directory and a personal information management agent into an intelligent Web Exploration Engine in a way which bridges the gaps between these seemingly unrelated tools. Our hybrid, for which we have developed a proof-of-concept prototype [Kalinov et al., 2010b], allows users to both locate specific data and to discover new information. Information discovery is served by a web directory which is built with the assistance of a dynamic hierarchical classifier we developed [Kalinov et al., 2010a]. The category structure achieved by it is also the basis of a large number of nested search engines, allowing information locating both in general (similar to a "standard" search engine) and in a variety of contexts selectable by the user.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
Full Text
11
Purdy, Graeme Robert. « Engine testing and modelling of transient fuelling control strategies for four-stroke engines ». Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388055.
Texte intégral
12
Varelis, Angelos G. « Technoeconomic study of engine deterioration and compressor washing for military gas turbine engines ». Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/9584.
Texte intégralRésumé :
Despite spending much of their operating life in clear air, aircraft gas turbine
engines are naturally prone to deterioration as they are generally not fitted
with air filters. Engines are particularly at risk during takeoff and landing, and
whilst operating in areas of pollution, sand, dust storms, etc. The build-up of
contaminants, especially on the compressor surfaces, leads to a dramatic
reduction in compressor efficiency, which gives rise to a loss of available
power, increased fuel consumption and increased exhaust gas temperature.
These conditions can lead to flight delays, inspection failures, withdrawal from
service, increased operating costs and safety compromises.With the growing
interest in life cycle costs for gas turbine engines, both engine manufacturers
and operators are investigating the tradeoffs between performance
improvements and associated maintenance costs.
This report introduces the problem of output and efficiency degradation in two
aero gas turbine engines (the T56–A–15 and the F110–GE–129) caused by
various deterioration factors. Their causes are broadly discussed and the
effects on powerplant performance are simulated and analyzed.
One of the key factors leading to performance losses during operation of
these engines is compressor fouling. The fouling can come from a wide
variety of sources; hydrocarbons from fuel and lubricating oils; volcanic ash;
pollen; marine aerosols; dust; smoke; pollution, etc. The presence of these
fouling sources acts as a bonding agent for the solid contaminants, ‘gluing’
them to the compressor surfaces. Thus, the aggravation in terms of power
output, fuel consumption and additional time to carry out a typical mission will
be assessed and an economic analysis will be attempted in order to quantify
the effects of compressor fouling on the additional costs which arise, because
of this specific deterioration.
The effect of compressor fouling can be maintained by frequent cleaning to
improve efficiency, resulting, hence, in improved power output, fuel savings
and prolonged engine life. Compressor cleaning is thoroughly presented, and
the implementation of on-wing off-line cleaning on the performance of the
F110 engine was investigated from a technical and economical standpoint.
Finally, according to the results obtained, the optimal frequency of compressor
washing for the F110 engine is estimated, in order to eliminate safety
compromises, improve performance and reduce the engine’s life cycle cost.
13
Kenny, Wilhelm Jordaan. « Development of an engine testing facility for spark ignition engine fuels ». Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80043.
Texte intégralRésumé :
Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This thesis comprises of the development of a facility were spark ignition engine fuels can be tested. Development of the facility included the installation of a standard spark ignition engine, an engine dynamometer, control and monitoring equipment, control and monitoring software, and an in-cylinder pressure measurement setup. The system was tested using petrol as well as a petrol-ethanol blend. The results indicated good accuracy and repeatability of the system. Analysis of the performance and combustion of the petrol-ethanol blend showed no significant difference in comparison to the petrol fuel. The petrol-ethanol blend showed a slight increase in oxygen content and fuel consumption as well as an increase in CO2 emissions and a decrease in CO emissions. During the project, a comparison was also made between the performance of fibre optic transducers and a piezoelectric transducer. It was found that the fibre optic transducers performed similarly to the piezoelectric transducer during low engine load conditions. At high load conditions however, the fibre optic transducers were not able to produce the same accuracy as the piezoelectric transducer.
AFRIKAANSE OPSOMMING: Hierdie tesis bestaan uit die ontwikkeling van 'n fasiliteit waar brandstowwe vir 'n vonkontsteking binnebrandenjin getoets kan word. Ontwikkeling van die fasiliteit sluit in die installering van 'n standaard vonkontsteking binnebrandenjin, 'n enjin rem, beheer en monitering toerusting, beheer en monitering sagteware, en 'n insilinder drukmeting opstelling. Die fasiliteit is getoets met suiwer petrol sowel as 'n petrol-etanol mengsel. Die resultate het hoë vlakke van akkuraatheid en herhaalbaarheid getoon. Ontleding van die werksverrigting en verbranding van die petrol-etanol mengsel het geen beduidende verskil getoon in vergelyking met die suiwer petrol brandstof nie. Die petrol-etanol mengsel het 'n effense toename in suurstofinhoud, brandstofverbruik, sowel as CO2 vrylating en 'n afname in CO vrylating getoon. Tydens die projek is 'n vergelyking getref tussen die akkuraatheid van optiese vesel drukmeters en 'n piësoëlektriese drukmeter. Daar is bevind dat die akkuraatheid van die optiese vesel drukmeters soortgelyk is aan die piësoëlektriese drukmeter gedurende lae enjin lastoestande. By hoë las omstandighede was die optiese vesel drukmeters egter nie in staat om dieselfde akkuraatheid as die piësoëlektriese drukmeter te handhaaf nie.
14
Norouzi, Shahrouz. « Interaction of diesel type fuels and engine fuel system components in compression ignition engines ». Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5369/.
Texte intégralRésumé :
Contact of fuels with engine components at low and elevated temperatures for various amounts of time is found to be challenging as this contact has several effects on engine fuel system components and fuels. Also, storage of fuels for a long period of time is found to have almost the same effect on both engine components and fuels upon engine use. In this thesis fuel and engine components’ contact have been studied for four typical metals used in the construction of many engine fuel systems; in form of pure or alloys (copper, aluminium, mild carbon steel and stainless steel), studied after contact with three of the currently available fuels for use in compression ignition engines. Ultra-low sulphur diesel fuel (ULSD) was used as the fossil fuel, rapeseed methyl ester (RME) as the first generation biofuel and finally gas-to-liquid (GTL) as the second generation of biofuel, obtained via the Fischer-Tropsch process. The investigation was performed in different sections: fuels and metals have been studied for any degradation after contact at low and high temperatures for short and long exposure times, and an understanding of the corrosion process and any degradation on both metals and fuels has been achieved; due to the high hygroscopic character of these fuels and the presence of possible impurities in the fuel, the investigation was extended for analysis of the effect of the presence or absence of absorbed water and dissolved air (in the form of Oxygen) in fuels on degradation and corrosion characteristics of these fuels.
15
Min, Kyoungdoug. « The effects of crevices on the engine-out hydrocarbon emissions in spark ignition engines ». Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12221.
Texte intégral
16
Lim, Emmanuel G. (Emmanuel Gocheco). « The engine reformer : syngas production in engines using spark-ignition and metallic foam catalysts ». Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100109.
Texte intégralRésumé :
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 133-135).
An experimental study was performed to assess the feasibility of performing methane (CH4) partial oxidation (POX) in two internal combustion engines: one equipped to perform spark-ignition (the "spark-ignited engine"), and the other containing a catalyst in the engine cylinder (the "catalytic engine"). The exhaust gases were rich in hydrogen- (H 2) and carbon monoxide- (CO), and could be used as synthesis gas ("syngas") for the synthesis of liquid fuels such as methanol. Conventional syngas production techniques are only economical on a large scale and cannot be transported to hard-to-reach gas sources, where gas-to-liquids (GTL) would have the biggest impact on the transportability of that gas. Engines could be deployed at these locations to produce syngas on a small scale and at low cost, as they benefit from the economies of mass production that have been achieved through advanced manufacturing techniques. We call this type of engine an "engine reformer". This thesis contrasts the results of performing methane POX in two different engine reformers, using atmospheric air as the oxidizer. One of four cylinders in a Yanmar 4TNV84T marine diesel generator was converted to ignite methane POX mixtures using a spark plug. Intake temperatures > 350 °C were required to minimize misfire. Exhaust H2 to CO ratios of 1.4 were achieved with methane-air equivalence ratios (0m) up to 2.0, while ratios of > 2.0 were achieved with hydrocarbon-air equivalence ratios (PHc) up to 2.8 with the assistance of hydrogen (H 2) and ethane (C 2H6). High equivalence ratios °PHC > 2.2 showed reduced CH4 conversion efficiency, therefore PHC = 2.2 (with H2 produced a good tradeoff between syngas quality and CH4 conversion. A single-cylinder Lister-Petter TRl diesel generator was used to perform methane POX using a palladium (Pd) washcoat catalyst deposited on a Fecralloy® disk. With > 150 °C intake temperatures, exhaust H2 to CO ratios of 1.0 were achieved with methane-air equivalence ratios (PM = 4.0 with varying amounts of CO2 to simultaneously perform methane dry reforming. Spark-ignition appeared to provide higher reliability, though tests will continue to be performed on the catalytic engine to optimize performance. A larger engine of a similar design to the spark-ignited Yanmar will be deployed at a demonstration plant in North Carolina to produce syngas at higher flow rates, and will be integrated with a liquids synthesis reactor to produce methanol.
by Emmanuel G. Lim.
S.M.
17
Ozdemir, Ali. « Experimental Investigation Of Use Of Canola Oil As A Diesel Fuel ». Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12609954/index.pdf.
Texte intégralRésumé :
In this study, canola oil has been selected for the test on a diesel engine and its
suitability as an alternative fuel has been examined. To decrease the high viscosity of
canola oil, the effect of temperature on viscosity has been researched. Then the fuel
delivery system has been modified to heat canola oil before injecting the oil into the
combustion chamber. Also, ethanol has been tested as an additive by blending with
canola oil. An experimental setup has been installed according to standards to carry
out tests. The set up has been controlled with a computer to take measurements more
precisely and to perform experiment automatically. Experimental investigations
have been conducted on a four cylinder, direct injection diesel engine.
Full load-variable speed tests have been conducted to evaluate engine performance
parameters. In addition 13 mode ESC test cycle has been performed to determine the
exhaust emissions. Engine performance and emissions characteristics of canola oil
and canola-ethanol blend containing 30% ethanol have been compared with those of
baseline diesel fuel. Experimental results show that engine performance decreased
for canola oil. Addition of ethanol into canola oil has been noticed to improve
performance a little with respect to pure canola oil. Although, maximum performance has been obtained with diesel fuel, minimum specifics energy cost is
obtained with canola oil. It has been observed that hydrocarbon (HC) emissions
decrease with canola oil, blending ethanol with canola oil increase HC emissions and
maximum values are read for diesel fuel. Carbon monoxide (CO) emissions have
been observed to be the highest for canola oil but blending ethanol has a decreasing
effect on CO emissions. As for particulate matter (PM), use of canola oil has been
seen to be more pollutant than diesel but adding ethanol in canola reduces PM
emissions significantly.
18
Bagheri, Amirhossein. « Preliminary Analysis of an Innovative Rotary Displacer Stirling Engine ». Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822801/.
Texte intégralRésumé :
Stirling engines are an external combustion heat engine that converts thermal energy into mechanical work that a closed cycle is run by cyclic compression and expansion of a work fluid (commonly air or Helium) in which, the working fluid interacts with a heat source and a heat sink and produces network. The engine is based on the Stirling cycle which is a subset of the Carnot cycle. The Stirling cycle has recently been receiving renewed interest due to some of its key inherent advantages. In particular, the ability to operate with any form of heat source (including external combustion, flue gases, alternative (biomass, solar, geothermal) energy) provides Stirling engines a great flexibility and potential benefits since it is convinced as engines running with external heat sources. However, several aspects of traditional Stirling engine configurations (namely, the Alpha, Beta, and Gamma), specifically complexity of design, high cost, and relatively low power to size and power to volume ratios, limited their widespread applications to date. This study focuses on an innovative Stirling engine configuration that features a rotary displacer (as opposed to common reciprocating displacers), and aims to utilize analytical and numerical analysis to gain insights on its operation parameters. The results are expected to provide useful design guidelines towards optimization. The present study starts with an overview of the Stirling cycle and Stirling engines including both traditional and innovative rotary displacer configurations, and their major advantages and disadvantages. The first approach considers an ideal analytical model and implements the well-known Schmidt analysis assumptions for the rotary displacer Stirling engine to define the effects of major design and operation parameters on the performance. The analytical model resulted in identifying major variables that could affect the engine performance (such as the dead volume spaces, temperature ratios and the leading phase angle). It was shown that the dead volume could have a drastic effect over the engine performance and the optimum phase angle of the engine is 90o. The second approach considers a non-ideal analytical model and aims to identify and account the main sources of energy losses in the cycle to better represent the engine performance. The study showed that the ideal efficiency and the non-ideal efficiency could have 15% difference that could have as an enormous effect on the engine performance.
19
Yarlagadda, Santosh. « Performance Analysis of J85 Turbojet Engine Matching Thrust with Reduced Inlet Pressure to the Compressor ». University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271367584.
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20
Manley, Karen Jane. « Factors leading to offshore manufacture of Australian inventions : the case of the orbital combustion process engine ». Thesis, Manley, Karen Jane (1994) Factors leading to offshore manufacture of Australian inventions : the case of the orbital combustion process engine. PhD thesis, Murdoch University, 1994. https://researchrepository.murdoch.edu.au/id/eprint/489/.
Texte intégralRésumé :
This thesis focuses on the factors which lead to off-shore manufacture of Australian inventions. It establishes this phenomenon as a problem, both in terms of its incidence in the post-war period, and in the strategic importance of innovative activity to economic growth. The thesis utilises a case study approach and concentrates on the experiences of one company, the Orbital Engine Corporation (Orbital). In 1989 Ralph Sarich, inventor of the Orbital Combustion Process (OCP) engine and founder of Orbital, signed an agreement with the Michigan state government to manufacture the engine in the United States of America (USA), in preference to several alternative sites in Australia and overseas. This occurred in the context of Orbital actively pursuing assistance from the Australian government to secure local production. The research question is: Why did Orbital decide to manufacture its engine invention ofshore? A multi-disciplinary approach to this question is adopted. Three different conceptual frameworks are employed: industrial organisation theory, market failure theory and policy network theory. The analysis is not structured around a pre-existing hypothesis; instead, the aim is to generate potential explanations for more rigorous testing by subsequent researchers.
The thesis concludes that, in terms of industrial organisation theory, the decision to manufacture OCP engines off-shore was a function of the poor quality of the Australian industrial context and the failure by those seeking assistance from the Commonwealth government to stress Orbital's status as an exemplary enterprise in Australian industry. Market failure theory indicated that offshore production of the OCP engine was made more likely by the suboptimal operation of the price mechanism, the neglect of market failure arguments by those supporting local production of the engine and 'government failure'. Policy network theory explained Orbital's decision as the result of: ineffective employment of negotiation tactics by proponents of the engine's domestic manufacture; and the chaotic nature of negotiations which allowed certain personal and ideological prejudices to dominate the issue resolution process.
It is shown that some or all of these explanations underlie a number of other examples where Australian inventions have been manufactured offshore. In commenting on policy implications, the thesis points to the economic potential of the Orbital invention and the value of interventionist industry policy. The thesis identifies a number of actions which might be taken to lower the incidence of foreign manufacture of Australian inventions. Further research is necessary to determine the relative importance of the various factors which are identified as leading to offshore production. In addition, there remains a particularly crucial need to improve the social efficiency of existing cost-benefit techniques employed by government policy-makers and commercial analysts.
21
Manley, Karen Jane. « Factors leading to offshore manufacture of Australian inventions : the case of the orbital combustion process engine ». Murdoch University, 1994. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20080115.124359.
Texte intégralRésumé :
This thesis focuses on the factors which lead to off-shore manufacture of Australian inventions. It establishes this phenomenon as a problem, both in terms of its incidence in the post-war period, and in the strategic importance of innovative activity to economic growth. The thesis utilises a case study approach and concentrates on the experiences of one company, the Orbital Engine Corporation (Orbital). In 1989 Ralph Sarich, inventor of the Orbital Combustion Process (OCP) engine and founder of Orbital, signed an agreement with the Michigan state government to manufacture the engine in the United States of America (USA), in preference to several alternative sites in Australia and overseas. This occurred in the context of Orbital actively pursuing assistance from the Australian government to secure local production. The research question is: Why did Orbital decide to manufacture its engine invention ofshore? A multi-disciplinary approach to this question is adopted. Three different conceptual frameworks are employed: industrial organisation theory, market failure theory and policy network theory. The analysis is not structured around a pre-existing hypothesis; instead, the aim is to generate potential explanations for more rigorous testing by subsequent researchers.
The thesis concludes that, in terms of industrial organisation theory, the decision to manufacture OCP engines off-shore was a function of the poor quality of the Australian industrial context and the failure by those seeking assistance from the Commonwealth government to stress Orbital's status as an exemplary enterprise in Australian industry. Market failure theory indicated that offshore production of the OCP engine was made more likely by the suboptimal operation of the price mechanism, the neglect of market failure arguments by those supporting local production of the engine and 'government failure'. Policy network theory explained Orbital's decision as the result of: ineffective employment of negotiation tactics by proponents of the engine's domestic manufacture; and the chaotic nature of negotiations which allowed certain personal and ideological prejudices to dominate the issue resolution process.
It is shown that some or all of these explanations underlie a number of other examples where Australian inventions have been manufactured offshore. In commenting on policy implications, the thesis points to the economic potential of the Orbital invention and the value of interventionist industry policy. The thesis identifies a number of actions which might be taken to lower the incidence of foreign manufacture of Australian inventions. Further research is necessary to determine the relative importance of the various factors which are identified as leading to offshore production. In addition, there remains a particularly crucial need to improve the social efficiency of existing cost-benefit techniques employed by government policy-makers and commercial analysts.
22
Catanese, Alessandro. « Emission characterization and cylinder pressure information for applications in the electronic engine management of diesel engines ». Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486702.
Texte intégralRésumé :
In the last few years, diesel engines for passenger cars and light commercial vehicles have achieved in Europe a level of success as never before and, to-· day, several manufacturers are looking at the US market for the close future. This has been possible thanks to the exploitation of turbocharging systems and highly flexible fuel injection equipment which have increased the specific power output of the engine, reducing in the same time the combustion noise and maintaining the high level of fuel efficiency typical of this kind of powertrain. On the other hand the complexity of diesel engines has increased exponentially, with the addition of several sensors and actuators necessary to monitor and control the correct working of the system. In order to achieve the increasing emission targets requested by European and US regulations, it is necessary not only to optimize the calibration of all the engine parameters, but also to ensure that the calibration setpoints are always achieved through an accurate control system. Moreover, it is necessary to be able to estimate how the tolerances errors of the engine sensors and actuators, inevitable in mass production equipment, will affect the robustness of the final engine outputs. In this thesis, experimental investigations have been executed on two different direct injection diesel engines, in order to characterize their emission behaviour and create some general prediction functions for the engine-out emission levels, based on mean value variables. These functions can be easily implemented in power plant engine models, in order to investigate the effect of deviations of single components on the whole engine system. Moreover, an explorative investigation has been carried out on the possible exploitation of in-cylinder pressure data for improving the control of the fuel injection and combustion, achieving an overall engine robustness advantage.
23
Costanzo, Vincent S. (Vincent Stanley) 1979. « Effect of in-cylinder liquid fuel films on engine-out unburned hydrocarbon emissions for SI engines ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65276.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2011."February 2011." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 265-270).
Nearly all of the hydrocarbon emissions from a modern gasoline-fueled vehicle occur when the engine is first started. One important contributing factor to this is the fact that, during this time, temperatures throughout the engine are low - below the point at which all of the components of the gasoline can readily vaporize. Consequently, any fuel that enters the combustion chamber in liquid form can escape combustion and subsequently be exhausted as hydrocarbon emissions. An experimental study was performed in a firing engine in which liquid gasoline films were established at various locations in the combustion chamber and the resulting impact on hydrocarbon emissions was assessed. Unique about this setup was that it combined direct visual observation of the liquid fuel films, measurements of the temperatures these films were subjected to, and the determination from gas analyzers of burned and unburned fuel quantities - all with cycle-level or better resolution. An increase in the hydrocarbon emissions was observed with liquid gasoline films present in the combustion chamber. This increase depended upon both the location of the film and the temperature of that location, and correlated with estimates of the mass of fuel in the film. The largest impact was observed when the head near the exhaust valve was wetted; the smallest impact was observed when the piston on the intake side of the engine was wetted. In general, as engine temperatures increased the hydrocarbon emissions due to the liquid fuel films decreased. It was also identified when, in the exhaust event, fuel from the films was actually exhausted. The effect of the location of the liquid fuel film can best be understood in terms of the time before flame arrival at that location, the local flow over the film, and the extent to which the overall flow in the combustion chamber carries fuel from the film to the exhaust valve. The primary effect of wall temperature is to affect the amount of vaporization from the film: as temperature increases more vaporization occurs before flame arrival, resulting in less fuel that can vaporize post-flame as unburned fuel emissions.
by Vincent S. Costanzo.
Ph.D.
24
Telesz, Mark P. « Design and Testing of a Thermoacoustic Power Converter ». Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11495.
Texte intégralRésumé :
Thermoacoustic engines convert heat into acoustic pressure waves with no moving parts; this inherently results in high reliability, low maintenance and low manufacturing costs. Significant increases in the performance of these devices have enabled rivalry with more mature energy conversion methods in both efficiency and power output. This optimal production of acoustic power can be ultimately used to achieve cryogenic temperatures in thermoacoustic refrigerators, or can be interfaced with reciprocating electro-acoustic power transducers to generate electricity.
This thesis describes the design, fabrication and testing of a Thermoacoustic Power Converter. The system interfaces a thermoacoustic-Stirling heat engine with a pair of linear alternators to produce 100 watts of electricity from a heat input. It operates with helium at 450 psig internal pressure and a hot side temperature of 1200F. Through thermoacoustic phenomena, these conditions sustain a powerful pressure wave at a system specific 100 Hz. This pressure wave is used to drive the two opposed linear alternators in equal and opposite directions to produce a single phase AC electrical output at that same system frequency. The opposing motion of the two alternators enables a vibration-balanced system.
The engine has created 110 watts of acoustic power and the complete Thermoacoustic Power Converter system has produced 70 watts of AC electricity. Compensating for some heat leaks, the converter reaches 26.3% heat to acoustic power efficiency and 16.8% heat to electric efficiency when those maximum values are achieved. This conversion of heat to acoustic power is 40% of the Carnot thermodynamic efficiency limit.
25
Vaish, Sarthak. « A study of the friction (piston-liner interaction) in internal combustion engines using a Floating Liner Engine ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108920.
Texte intégralRésumé :
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 88-91).
With the increasing interest in decreasing the environmental impact from internal combustion engines as well as increasing the fuel efficiency has led to deeper investigation into the components of the engine. The mechanical friction in an engine is a major concern, any improvements or reductions in friction can have large implication on the' efficiency of the engines. This thesis focuses on the piston/ ring pack assembly and its contribution to friction. It investigates several key components and trends in friction for the piston/ ring pack assembly, specifically the trends related to the oil control ring and the liner surface. The Floating Liner Engine is used in this study to isolate results from different components. The data collected can be used for comparative analysis and to identify trends in the friction trace. The thesis starts with describing the Floating Liner Engine system at MIT in detail. Both the data collection and the hardware systems are described as well as the test capabilities of the Floating Liner Engine. The results used in the thesis have been collected using the motoring condition. The oil control ring plays a key role in controlling the supply of oil to the top two rings and hence has a higher tension that the top two rings. This leads to the oil control ring having a significant contribution to the total friction of the system. The two most prevalent oil control rings used in the industry are the twin land oil control ring (TLOCR) and the three piece oil control ring (TPOCR). The thesis investigates the effect of changing liner roughness on the friction of the TLOCR. A comparison between the TLOCR and the TPOCR is also performed using the same liner surfaces. The results from these studies show a marked difference between the friction traces from the two oil control rings.
by Sarthak Vaish.
S.M.
26
Welling, Orian. « Megaknock in downsized engines : the impact of engine lubricants on pre-ignition, and the scope for improvement ». Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608144.
Texte intégral
27
Ford, Sean T. « Aerothermodynamic cycle design and optimization method for aircraft engines ». Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53006.
Texte intégralRésumé :
This thesis addresses the need for an optimization method which can simultaneously optimize and balance an aerothermodynamic cycle. The method developed is be able to control cycle design variables at all operating conditions to meet the performance requirements while controlling any additional variables which may be used to optimize the cycle and maintaining all operating limits and engine constraints. The additional variables represent degrees of freedom above what is needed for conservation of mass and energy in the engine system. The motivation for such a method is derived from variable cycle engines, however it is general enough to use with most engine architectures. The method is similar to many optimization algorithms but differs in its implementation to an aircraft engine by combining the cycle balance and optimization using a Newton-Raphson cycle solver to efficiently find cycle designs for a wide range of engine architectures with extra degrees of freedom not needed to balance the cycle. Combination of the optimization with the cycle solver greatly speeds up the design and optimization process. A detailed process description for implementation of the method is provided as well as a proof of concept using several analytical test functions. Finally, the method is demonstrated on a separate flow turbofan model. Limitations and applications of the method are further explored including application to a multi-design point methodology.
28
Pavelec, Sterling Michael. « The development of turbojet aircraft in Germany, Britain, and the United States : a multi-national comparison of aeronautical engineering, 1935-1946 / ». The Ohio State University, 2004. http://www.ohiolink.edu/etd/send-pdf.cgi/Pavelec%20Sterling%20Michael.pdf?acc_num=osu1082396007.
Texte intégral
29
Bjugstad, Line. « Study of the role of engine control in the value chain for biofuels in modern "ultra clean" engines ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24832.
Texte intégralRésumé :
The climate changes caused by the combustion of fossil fuels in the transportation sector have, along with a decrease in fossil fuel reserves, resulted in an increased interest in developing alternative fuels. Biofuels are one of the most prominent options and with an expansion in the use of these fuels, it is important to understand all aspects of the environmental effect they impose.First generation biofuels are the commercial available biofuels today. Since their feedstock origins from food and oil-seed crops there is a great skepticism around their sustainability, creating a focus on research and development of second generation and advanced biofuels. These fuels are more environmental beneficial, however expensive to produce due to a more complex structure of the feedstocks. This requires a more advanced conversion technology, and additionally research is needed to make these fuels economically competitive. Fischer Tropsch Diesel (FTD) is one of the most promising second generation biofuels, yielding great reduction in greenhouse gas (GHG) emissions and fossil fuel consumption when looking at its whole life cycle. There are uncertainties around the combustion characteristics and the end use emissions of the different biofuels. This especially applies to the use of biofuels in blend with diesel, which is the most common form of utilizing biofuels today. In order to increase the use of these fuels the uncertainties need to be fully explored to ensure their sustainability. This research has traditionally been performed experimentally, but later years computational simulation has arisen as a powerful tool. It saves time and cost, and can also reveal information not possible to obtain by experiments in real engines. In order to obtain reliable results from the simulations, both high quality physical and chemical models are required. In this thesis a Stochastic Reactor Model (SRM) is used, where the volume in the cylinder is divided into a number of smaller volumes. These are known as particles and have their own chemical composition, temperature and mass. Since the SRM is a 0-dimensional model no characteristics regarding the position in space are given, but a Probability Density Function (PDF) gives a distribution of the properties of the particles and enables them to mix and exchange heat with the cylinder walls. By doing so the model takes into account in-homogeneities and turbulence. The engine type used is a direct injection compression ignition (DICI) engine where fuel is directly injected, hence good models are required for both the mixing process as well as the chemical kinetics. The chemical models used for simulations should withhold the same characteristics as the original fuels, however due to time limitations for the computational calculations less important species and reaction paths should be eliminated. This is done through a reduction process, where there always exists a trade-off between the quality of the model, and the time consumption. The chemical models applied in this thesis are substitutions and simplifications of the original fuels, namely diesel and FTD. N-heptane (nC7H16) has been used as a surrogate fuel for diesel, while the fuel composition representing FTD is 0.772 nC14H30, 0.047 C14H30-2 and 0.181 C14H28-1. The simulations have been run for the engine speeds 900rpm, 1500rpm and 2500rpm, with altered fuel injections to approximate real engine conditions. To save computational time most of the cycles have been run from -20CAD to 60CAD, with inlet gas temperature and pressure of Ti=700K and Pi=2.33E06N/m2. The combustion characteristics of the different fuels and engine settings have been compared with regard to parameters such as pressure and temperature profiles, heat release, converted fuel and the production of the criteria pollutants CO, CO2 and NOx. Only small alterations in the combustion cycle is seen for the FTD surrogate with regard to n-heptane, which is most likely an effect of the substantial simplifications applied in the models. These simplifications were also evident in the last part of the thesis, where the emission profiles from the simulations were compared to experimental values. Here some of the cases showed deviating results, however others had correlating trends and could be qualitatively validated. The injection profiles were tuned with regard to the point of injection, where advanced injections obtain higher temperature and pressure peaks. Accordingly more work is produced, however also elevated levels of NOx. The effect of Exhaust Gas Recirculation (EGR) has been tested, where the NOx emissions are expected to diminish due to reduced concentration of oxygen. Here huge NOx reductions are observed, but also a trade-off with regard to elevated levels of CO and reduced levels of CO2. This reflects the main problem to be resolved when applying EGR, namely to what extent EGR should be applied before the negative effects related to a more incomplete combustion surpasses the NOx savings.
30
Rounce, Paul Lindsey. « Engine performance and particulate matter speciation for compression ignition engines powered by a range of fossil and biofuels ». Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2812/.
Texte intégralRésumé :
Fuels: Non-renewable fossil fuels are the largest man-made contributor to global warming. Biofuel market share will increase, promoted by renewability, inherent lower net CO\(_2\) emissions, and legislation. The environmental and human health impact of diesel exhaust emission particulate matter (PM) is a major concern. Fossil diesel PM aftertreatment systems exist. Near future fuel PM research and the evaluation of current aftertreatment technology, highlight a route for future development. Using a holistic approach this body of work studies the interdependence between the fuel, the CI engine and associated aftertreatment system. The overall objective of this thesis is the evaluation of current diesel aftertreatment using renewable near future fuels. Diesel blends with 1st and 2nd generation biodiesel fuels are viable. Carefully selected blends like B20G10 can make all round regulated emission improvements. Green additive dimethyl carbonate (DMC) enhances diesel combustion by oxygenation. Regulated emissions of THC, CO (>30% reduced) and PM (50% reduced) for 2% DMC in diesel. 1st generation biodiesel (RME) is widely available. Combustion produces significantly less solid PM than diesel (<50%) and slightly more liquid PM. RME produces less particulate at nearly all particle sizes, but more of the small nano sized liquid SOF. The potentially negative health effect of nano-sized SOF material raises questions. There is a case for more research into the health effects of nano-sized SOF material. Oxygenated fuel combustion PM contains more voids (facilitates DPF oxidation), plus unregulated carcinogenic compounds are reduced. ii Aftertreatment: The efficiency of the oxidation catalyst for the near future fuels was comparable to diesel and PM matter at all particulate sizes is reduced for all near future fuels tested. Aftertreatment total PM filtration levels are >90% by mass >98% by number, for all fuels. For synthetically produced 2nd generation gas to liquid (GTL) fuels there are potentially DPF regeneration implications. Current aftertreatment solutions are as effective for bio alternatives as they are for fossil diesel. Biodiesels, green additives and aftertreatment are effective clean emissions improvements, until the promise of true zero emission vehicles is realised.
31
Johns, R. A. « The analysis of the combustion of methanol in lean-burning, high-compression engines using an engine combustion model ». Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/847267/.
Texte intégralRésumé :
Alcohol fuels are expected to become an economic/strategic alternative to oil over the next decade as oil reserves are depleted and countries seek to become more energy self-sufficient. Methanol, produced from natural gas deposits, and ethanol, produced locally by distillation of biomass, offer easily transportable alternatives. The use of a wider range of fuels in spark-ignition engines and the quest for fuel economy whilst meeting exhaust emissions legislation are important issues in engine design. The performance of current and proposed combustion chamber designs needs to be assessed with lean mixtures of both conventional and alternative fuels. The parameters defining combustion chamber performance, initial flame development and cycle-to-cycle variations in combustion may be readily determined using computer in-cylinder combustion models in a diagnostic manner to reduce experimentally acquired cylinder pressure data. This thesis develops and applies two analysis techniques to the study of the combustion of methanol in the lean burning regime with experimental results from three engines. The pressure increment technique, in which the pressure rise owing to combustion at constant volume is computed, is suitable for use directly on microcomputer systems. The two-zone equilibrium theory model, in which the mass burnt to give the measured pressure rise is evaluated, provides a more comprehensive analysis but is demanding in computer power. Higher burning rates were achieved using highly turbulent combustion chambers with methanol and equivalence ratios could be leaned to about 0.8 before cycle-to-cycle variations in combustion limited stable operation. The results obtained indicated the significant phases of initial flame development, the influence of early flame development on subsequent burning rates, and the influence of differing chamber geometries on performance. The combustion process was modelled for use in parametric studies of engine performance based on empirical data.
32
Henriksson, Adam. « Alternative Search : From efficiency to experience ». Thesis, Umeå universitet, Institutionen Designhögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97836.
Texte intégralRésumé :
Search engines of today are focusing on efficiently and accurately generating search results.Yet, there is much to be explored in the way people interact with the applications and relate to the content. Individuals are commonly unique, with complex preferences, motives and expectations. Not only is it important to be sensitive to these differences, but to accommodate the extremes. Enhancing a search engine does not only rely on technological development, but to explore potential user experiences in broader perspectives - which not only gratifies the needs for information, but supports a diversity of journeys. The aim of the project is to develop an alternate search engine with different functionality based on new values that reflects contemporary needs. The result, Exposeek, is an experiential prototype supporting exploratory browsing based on principles of distributed infrastructure, transparent computation and serendipitous information. Suggestive queries, legible algorithms and augmented results provide additional insights and present an alternative way to seek and peruse the Web.Search Engines, Interaction Design
33
Voda, Tomáš. « Modelování a řízení leteckých proudových motorů ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316391.
Texte intégralRésumé :
This thesis deals with the description of aircraft engines, their control requirements and control possibilities of these engines. In the practical part, the Jetcat P80-SE engine model was created. This model was then verified against a real engine with measured actual engine speed and temperature. These parameters were then compared with simulated engine speed and temperature. Due to this comparison we can say that it was possible to create a model of the engine that corresponds to the real engine. In addition, the speed controller was designed to meet the control requirements over the speed range. A PI speed controller was designed in different variants, the variants were then compared. Due to the safety limits of the manufacturer were not known, limit values were only implemented to show how the limitation could be implemented.
34
Ma, Qi. « Model based control and efficient calibration for crank-to-run transition in SI engines ». Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1125429289.
Texte intégralRésumé :
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xiii, 160 p.; also includes graphics (some col.). Includes bibliographical references (p. 156-160). Available online via OhioLINK's ETD Center
35
Hoegel, Benedikt. « Thermodynamics-based design of stirling engines for low-temperature heat sources ». Thesis, University of Canterbury. Mechanical Engineering, 2014. http://hdl.handle.net/10092/9344.
Texte intégralRésumé :
Large amounts of energy from heat sources such as waste-eat and geothermal energy are available worldwide but their potential for useful power-generation is largely untapped. This is because they are relatively low temperature difference (LTD) sources, in the range from 100 to 200 °C, and it is thermodynamically diffcult, for theoretical and practical reasons, to extract useful work at these temperatures. This work explores the suitability of a Stirling engine (SE) to exploit these heat sources. Elsewhere much work has been done to optimise Stirling engines for high temperature heat sources, but little is known about suitable engine layouts, and their optimal design and operational aspects at lower temperature differences. With the reduced temperature difference, changes from conventional engine designs become necessary and robust solutions for this novel application have to be identified.
This has been achieved in four major steps: identification of a suitable engine type; thermodynamic optimisation of operating and engine parameters; optimisation of mechanical efficiency; and the development of conceptual designs for the engine and its components informed by the preceding analysis. For the optimisation of engine and operating parameters a model was set up in the commercial Stirling software package, Sage, which also has been validated in this thesis; suitable parameter combinations have been identified.
This work makes key contributions in several areas. This first is the identification of methods for better simulating the thermodynamic behaviour of these engines. At low temperature differences the performance of Stirling engines is very sensitive to losses by fluid friction (and thus frequency), adiabatic temperature rise during compression, and the heat transfer from and to the surroundings. Consequently the usual isothermal analytical approaches produce results that can be misleading. It is necessary to use a non-isothermal approach, and the work shows how this may be achieved.
A second contribution is the identification of the important design variables and their causal effects on system performance. The primary design variable is engine layout. For an engine having inherently low efficiency due to the low temperature difference it is important to choose the engine layout that provides the highest power density possible in order to minimise engine size and to save costs. From this analysis the double-acting alpha-type configuration has been identified as being the most suitable, as opposed to the beta or gamma configurations. An-other key design variable is working fluid, and the results identify helium and hydrogen as suitable, and air and nitrogen as unsuitable. Frequency and phase angle are other design variables, and the work identifies favourable values. A sensitivity analysis identifies the phase angle, regenerator porosity, and temperature levels as the most sensitive parameters for power and efficiency. It has also been shown that the compression work in low-temperature difference Stirling engines is of similar magnitude as the expansion work. By compounding suitable working spaces on one piston the net forces on the piston rod can be reduced significantly. In double-acting alpha-engines this can be achieved by choosing the Siemens as opposed to the Franchot arrangement. As a result friction and piston seal leakage which are two important loss mechanisms are reduced significantly and longevity and mechanical efficiency is enhanced. Design implications are identified for various components, including pistons, seals, heat exchangers, regenerator, power extraction, and crankcase. The peculiarities of the heat source are also taken into account in these design recommendations.
A third key contribution is the extraction of novel insights from the modelling process. For the heat exchangers it has been shown that the hot and cold heat exchangers can be identical in their design without any negative impact on performance for the low-temperature difference situation. In comparison the high temperature applications invariably require different materials and designs for the two heat exchangers. Also, frequency and phase angle are found to be quite different (lower frequency and higher phase angle) from the optimum parameters found in high temperature engines. Contrary to common belief the role of dead volume has been found to play a crucial and not necessary detrimental role at low temperature differentials.
Taken together, the work is positioned at the intersection of thermodynamic analysis and engineering design, for the challenging area of Stirling engines at low temperature differences. The work extracts thermodynamic insights and extends these into design implications. Together these help create a robust theoretical and design foundation for further research and development in the important area of energy recovery.
36
Mello, Claudio Coelho de. « Projeto e construção de um condicionado de combustiveis ». [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263066.
Texte intégralRésumé :
Orientador: Paulo Roberto Gardel KurkaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-11T04:00:47Z (GMT). No. of bitstreams: 1 Mello_ClaudioCoelhode_M.pdf: 11766357 bytes, checksum: 5f2659f4a4238bfbfaa4dd0e10c50790 (MD5) Previous issue date: 2006
Resumo: This study evaluates the existing technology of converting the various residues in oil refineries and compares with the new technology of that the Grupo Combustíveis Alternativos (GCA), in conjunction with Petrobras and CENPES would apply to the conversion of the residue of the Vacuum distillation. Also studied is one of the components of the reactor Fast Pyrolysis developed in the GCA during phase two of Presat. This component is the injector and its study helps improve the reactor built for stage three from Presat. For the study were assembled two spout equipment, the first directed to study the behavior of the flow of droplets inside the reactor and the second for the purpose of measuring the distribution of droplets generated by the size of the nozzle
Abstract: This study evaluates the existing technology of converting the various residues in oil refineries and compares with the new technology of that the Grupo Combustíveis Alternativos (GCA), in conjunction with Petrobras and CENPES would apply to the conversion of the residue of the Vacuum distillation. Also studied is one of the components of the reactor Fast Pyrolysis developed in the GCA during phase two of Presat. This component is the injector and its study helps improve the reactor built for stage three from Presat. For the study were assembled two spout equipment, the first directed to study the behavior of the flow of droplets inside the reactor and the second for the purpose of measuring the distribution of droplets generated by the size of the nozzle
Mestrado
Projeto Mecanico
Mestre em Engenharia Mecânica
37
Weinrotter, Martin [Verfasser]. « Laser Ignition of Internal Combustion Engines : Basic Laser and Ignition Optics Developments, Engine Application and Optical Diagnostics / Martin Weinrotter ». München : GRIN Verlag, 2011. http://d-nb.info/1182238203/34.
Texte intégral
38
Cho, Yeunwoo 1973. « Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines ». Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30302.
Texte intégralRésumé :
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Page 172 blank.
Includes bibliographical references (p. 129-130).
A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption that the multi-grade oil can be modeled as a compound of several distinct paraffin hydrocarbons, a set of equations governing the oil vapor density variations were derived by applying the mass conservation law to the amount of oil vaporized from the piston and the amount of oil vapor transported within the piston ring pack. The model was applied to a heavy-duty diesel engine. First, the case with the maximum oil supply to all the piston regions was studied and the results showed that, under this condition, the oil consumption from vaporization alone was far greater than the typical oil consumption value measured in the engine. Then, to show the contribution of oil vaporization to oil consumption and the dependence of vaporization on oil supply to different regions, different lubrication conditions for the high temperature regions of the piston were studied. Finally, a liquid oil transport model was integrated with this oil vaporization model in order to investigate the change of oil composition on the crown land with each engine cycle and the contribution of liquid-phase oil and vapor-phase oil to the total oil consumption under a fixed liquid oil supply rate to the crown land.
by Yeunwoo Cho.
S.M.
39
Westerfield, Zach. « A study of the friction of the power cylinder system in internal combustion engines using a floating liner engine ». Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100347.
Texte intégralRésumé :
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 117-120).
The recent worldwide quest to increase the fuel efficiency of internal combustion engines has led to great effects to reduce friction of many of the components in these engines. One area of major concern pertaining to this area is the friction of the piston/ring pack assembly. Because of the importance and necessity of this component to the internal combustion engine, any improvements can have relatively large implications for friction reduction. The purpose of this paper is to investigate several key components of the piston/ring pack assembly and how they influence friction levels. Specifically, experimental friction trends related to the oil control ring, piston skirt, liner surface and lubricant will be discussed. The Floating Liner Engine is used in this study in both the motored and fired configuration to isolate results from components and provide data for comparative analysis. The oil control ring (OCR) controls the supply of lubricating oil to the top two rings of the ring pack and has a significant contribution to friction of the system. This study investigates the two most prevalent types of OCR in the automotive market: the twin land oil control ring (TLOCR) and three piece oil control ring (TPOCR). The effect of changing the land width and spring tension on different liner surfaces for the TLOCR is investigated, and distinct trends are identified. A comparison is then done between the TLOCR and TPOCR on different liner surfaces. Results showed the TPOCR displayed different patterns of friction compared the TLOCR in certain cases. The piston skirt is also an important contributor of friction in the piston assembly. This thesis discusses the investigation into low friction coatings on the piston skirt. A brief study of piston skirt patterns is presented, with little gains being made by applying patterns the piston skirt coating. Next the roughness of the piston skirt coating is analyzed, and results show that reducing piston skirt roughness can have positive effects on friction reduction. Finally, an introductory study into the profile of the piston skirt is presented, with the outcome being that friction reduction is possible by optimizing the skirt profile. The final section of this thesis discusses the effects of lubricants pertaining to friction in the piston assembly. The effects of changing lubricant viscosity through both temperature and formulation are presented, as well as results from testing the effects of select anti-wear additives in the oil. The results identify new developments related to lubricant/additive effects on the liner surface, and how these effects can influence friction.
by Zach Westerfield.
S.M.
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Skidmore, F. W., et n/a. « The influence of gas turbine combustor fluid mechanics on smoke emissions ». Swinburne University of Technology, 1988. http://adt.lib.swin.edu.au./public/adt-VSWT20070420.131227.
Texte intégralRésumé :
This thesis describes an experimental program covering the development of certain
simple combustion chamber modifications to alleviate smoke emissions from the
Allison T56 turboprop engines operated by the Royal Australian Air Force.
The work includes a literature survey, smoke emission tests on two variants
of the T56 engine, flow visualisation studies of the combustion system in a
water tunnel and combustion rig tests of a standard combustor and four possible
modifications. The rig tests showed that reductions in smoke emissions of
80% were possible by simple modifications that reduced the primary zone
equivalence ratio and improved mixing in that zone.
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Олефіренко, Олег Михайлович, Олег Михайлович Олефиренко, Oleh Mykhailovych Olefirenko, Юлія Андріївна Сірік, Юлия Андреевна Сирик et Yuliia Andriivna Sirik. « Використання пошукової оптимізації сайту як засіб маркетингових комунікацій ». Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/12295.
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Adinolfi, Allegra. « ENGINE – ENel Global INtellingent Engine ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Trouver le texte intégralRésumé :
Engine is the newest solution developed by the Integration Platform Team that
will help Enel to manage, in the most efficient and innovative way, the document
inbound. It is a generic platform, highly configurable for all the use cases,
completely based on ML technique to recognize, classify and retrieve needed data
from specific documentation in order to automate as many processes as possible.
Engine is a novelty not only because of the AI techniques implemented but also
because it will lead people to fastly move towards a data-driven mentality that
today is crucial for such a big company like Enel. In general, the automation of
many processes that Engine is bringing and that today are still managed by
operators will definitely bring many time and economic savings. This work
describes the path faced to give life to Engine, starting from the concretization of
the idea to replace the solution as is, developing at first the business plan,
building the core component of the project giving life to the ML Models,
engineering the solution and finally monitoring the performances in production to
define what will be the next steps and challenges to face.
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GRASSI, ANDREA STEFANO. « VALORIZATION OF SECONDARY METAL RESOURCES THROUGH HYDROMETALLURGICAL PROCESSES ». Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/920992.
Texte intégralRésumé :
Abstract
This executive doctorate project comes from the collaboration between the company Engitec Technologies S.p.A. and the Università degli Studi di Milano. The student joined the company staff, gaining access to the company laboratories and pilot plants.
The project was focused on the study and optimization of hydrometallurgical processes for the recovery of metals from secondary resources. The two hydrometallurgical processes object of this work are proposed as alternatives to the state-of-the-art technologies applied worldwide for the recovery of zinc and lead. These two processes are capable to produce zinc and lead metals at high purity, avoiding purification and pyrometallurgical steps.
Through a critical analysis of the available literature, research work initially focussed on the comprehension of the mechanisms and reactions at the base of the recovery processes. New alternative ways and optimizations were then put forward. In addition, thanks to a period spent working directly on a pilot plant installed in South Africa, identification of industrial-scale issues was pursued.
As a result of this experimentation, many improvements were proposed and unravelled, resulting in ad-hoc equipment and concepts, conference presentations and a patent. The doctorate work brought to a series of steps forward in the comprehension and development of these processes, and to the permanent employment of the student in the company staff.
Summary
Reserves of natural resources are limited and nowadays it is necessary to pay more and more attention to the opportunities that a circular economy can provide. The technologies objects of this study are proposed as sustainable solutions to the shortage of raw materials from primary sources. The zinc technology is able to extract metal from zinc-bearing materials, as steel mill dusts, electrolysis wastes, mineral ores, and by-products. The Lead technology is able to extract lead metal directly from lead-acid-battery pastes; however, it can be applied in many other fields, as Cu/Au/Ag/Zn refining processes.
These processes are based on hydrometallurgical approaches and avoid completely the high-temperatures treatments typical of pyrometallurgy. At the same time, the peculiar chemistry of Engitec processes (based on ammonium chloride) leads to a simpler series of treatments, as the removal of the chlorine-washing step in the standard Zinc sulphate electrolytic process.
The Zero Liquid Discharge policy (ZLD) is adopted by the company for all hydrometallurgical processes, implying that no liquid effluents are released in the environment. The side-streams of the plants are designed to be solid products or by-products, decreasing the water and CO2 footprint as much as possible.
The two processes for recovering zinc and lead are called EZINEX® and F.A.S.T. respectively and are based on the same concept with minor differences. The research focused primarily on the EZINEX® process due to market-related reasons.
The first step is the leaching of the target metal using concentrated ammonium chloride solutions: the achievement of high extraction yields is one of the essential elements for these processes. The problem related to the presence of zinc-ferrites in steel mill dust was addressed by testing different reducing agents, although a satisfying solution is still to be found.
From the experience gained on the pilot plant installed in South Africa, it was possible to notice that the presence of calcium in solution is harmful for the plant heat exchangers. It was hypothesized and verified with experimental tests the possibility to keep under control the calcium concentration through the controlled precipitation of calcium sulphate without the addition of further reagents and using the ammonium sulphate that is generated in the scrubber.
During the leaching step, chemical species other than zinc are also brought into solution. Final metal at high purity can be obtained only if these species are managed and removed before electrolysis. Examples of these impurities are copper, silver, manganese, lead, and cadmium. Manganese is removed by the addition of permanganate that transforms the dissolved manganese into a filterable manganese dioxide, by a comproportion redox reaction. Other metal species (Cu, Ag, Pb, Cd) are removed exploiting a cementation reaction.
The analysis of demanganization reaction was performed by kinetic studies, together with electrochemical and chimico-physical experiments. A connection between the redox potential and the Mn(II) concentration was pointed out, and a mathematical function correlating the redox set-point and the plant solution pH was derived. This equation is able to control the on-field equipment to optimize the reagent consumption. At the same time, separation of the solid manganese oxide product was improved by exploring techniques alternative to simple filtering, as: i) flocculating agents, and ii) the most promising centrifugal solid-liquid separation.
Cementation of copper, silver, cadmium, and lead by addition of metallic zinc powder has a considerable impact on the cost of refined zinc. Therefore, alternative methods to perform this purification were evaluated.
A first study involved the testing of a rotary reactor loaded with metallic zinc pellets. A refresh of the zinc active surface, covered by the reaction products, is achieved by mixing and friction between the zinc pellets. A consequent increase in reaction yield was proved by investigating the influence of solution flow rate, rotation speed, and Zinc load. In addition, the necessary zinc for the cementation reaction can be self-produced by simple treatments of the electrolyzed zinc metal.
A second alternative to zinc metal powder is the use of an electrodepuration cell. By polarising the cathodes of the cell to a certain potential it is possible to selectively reduce various interfering cations without the use of chemical reagents. Initially the reduction potentials of the interferents were determined and then different lab-scale cell configurations were realized and tested. The potentialities of this technique were confirmed. However, optimization of the cell design is still an open question.
The electrolysis cell is the final step of the process. Zinc is reduced to its metallic form using electrical current. A fundamental aspect of this process is represented by the choice of the anodic material. The advantage of using activated titanium electrodes is a reduction in power consumption of about 17%, however, the use of activated titanium requires precise considerations, such as the absence of manganese in the electrolysis solution. The effect of manganese on the stability of these catalytic electrodes was studied and it was concluded that manganese is deleterious to their durability.
The metallic zinc deposit of the plant quality was analysed. Several commercial additives were applied to increase the compactness and smoothness of the deposit. The campaign of experiments led to identify as the best additive a mixture of gum arabic, aescine and agar.
The development of the technology involved chemical/engineering/industrial challenges with consequent advantages and disadvantages. This doctorate, starting from Engitec previous experience, explored and solved some problems, partly detectable only in a pre-industrial plant such as the one built in South Africa.
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He, Yuesheng. « Effect of intake primary runner blockages on combustion characteristics and emissions in spark ignition engines ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1190053207.
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Potužáková, Karolína. « Změna v přístupech v SEO po updatech Penguin a Panda ». Master's thesis, Vysoká škola ekonomická v Praze, 2014. http://www.nusl.cz/ntk/nusl-198614.
Texte intégralRésumé :
Search engine algorithms are constantly improved in order to provide the highest quality and most relevant results for the user. Google algorithm updates called Panda and Penguin have recently been one of the most significant and many websites that use black hat SEO techniques were hit by them. Nowadays, using this search optimization's techniques raises the risk of Google penalty, which in most of the cases cause decrease in traffic from organic search. The aim of this thesis is to describe techniques of search engine optimization (SEO) and their possible impact on website's ranking. The thesis also aims to verify whether Penguin and Panda updates have the impact on websites for which the methods of black hat SEO have been used and specify the result of this impact. In the theoretical part of this thesis it is described function of search engines Seznam.cz and Google, their algorithm change in history and possible factors on which the ranking score is based. Briefly are also described tools, which can be used to identify and analyze possible causes of penalization. After reading this thesis, the reader will have a basic orientation in search engine optimization methods and their appropriate use. Also, he will be able to recognize possible causes of Google penalty and propose an appropriate strategy for its removal.
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Ndame, Ngangue Max Keller. « Etude théorique, conception, réalisation et essai préliminaire d'un moteur à air chaud à pistons liquides ». Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3004/document.
Texte intégralRésumé :
Un moteur Ericsson est un moteur alternatif à apport de chaleur externe fonctionnant selon un cyclethermodynamique de Joule. Ce type de moteur est particulièrement intéressant pour la valorisationde certaines "sources chaudes" (l'énergie solaire, la biomasse, les effluents gazeux chauds...).Dans cette thèse, une configuration innovante de moteur est proposée. Celle-ci permet d'une part,de s’affranchir du problème d’étanchéité autour des pistons des moteurs Ericsson, par l'usage despistons liquides en lieu et place des pistons mécaniques et d'autre part, de simplifier le système dedistribution mécanique des moteurs conventionnels par l'usage de soupapes commandéesparticulières, dont l'ouverture est déclenchée par contact avec le piston. Ce type de moteur estadapté pour la production d'électricité de petite puissance (jusqu'à... 10 kW).Trois lois différentes de commande des soupapes du cylindre de détente du moteur à air chaudproposé sont étudiées et leurs influences sur la conception et les performances énergétiques dusystème sont présentées. En raison de la masse importante d'eau dans le système, un modèle quiprend en compte la dynamique des colonnes de liquide est développé. Ce modèle permet de prédireles performances d'un premier prototype expérimental.Un prototype de machine de détente a ensuite été conçu et réalisé dans notre laboratoire. Uneprésentation du prototype et du banc d'essai est faite, et les résultats d'un essai préliminaire sontprésentés. Malgré le caractère préliminaire de ces résultats, ils sont très encourageants car d'unepart, ils n'ont pas révélés de problèmes techniquement délicats à résoudre, et d'autre part ils ontpermis de tirer de nombreux enseignements pour la suite des travaux à mener sur le prototypeAn Ericsson engine is a reciprocating external heat input engine operating on a Joule thermodynamiccycle. This type of engine is particularly interesting for the valorization of certain "hot sources" (solarenergy, biomass, hot gaseous effluents ...).In this thesis, an innovative engine configuration is proposed. This allows, on the one hand, toovercome the problem of tightness around the pistons of Ericsson engines, by the use of liquidpistons instead of mechanical pistons and on the other hand, to simplify the mechanical distributionsystem of conventional engines by the use of particular actuated valves, whose opening is triggered by contact with the piston. This type of motor is suitable for the production of electricity of smallpower (up to... 10 kW).Three different valve command laws for the proposed hot air motor expansion cylinder are studiedand their influences on the design and energy performance of the system are presented. Due to thelarge amount of water in the system, a model that takes into account the dynamics of the liquidcolumns is developed. This model makes it possible to predict the performances of a firstexperimental prototype.A prototype of the expansion machine was then designed and built in our laboratory. The prototypeand the test bench are presented together with the preliminary test results. Despite the preliminarynature of these results, they are very encouraging because, on the one hand, they have not revealedany technically difficult problems to be solved, and on the other hand they have made it possible todraw many lessons for the further work to be done lead on the prototype
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Ridley, Sara J. « Increasing the efficiency of engine remanufacture by optimising pre-processing inspection : a comprehensive study of 2196 engines at Caterpillar Remanufacturing in the UK ». Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22549.
Texte intégralRésumé :
Remanufacturing describes the process of bringing used product to an "as-new" functional condition using reclaimed and new components. It is an industrial process operating across the automotive, industrial, commercial and domestic sectors which, despite its low profile, contributes around £2.35 billion annually to the UK economy. Remanufacturing is an enabler for manufacturing, reducing the use of virgin materials and energy thus allowing more cost-effective manufacturing. Key issues for remanufacturers revolve around the lack of industry-specific tools and techniques and this particularly affects effective decision-making for production issues such as the inspection of returned cores and their constituent components. The main aim of the research was to establish the factors that affect pre-processing inspection and this was achieved using causal true-experimental research into the overall remanufacturing process for over two thousand engines at a Caterpillar Remanufacturing pl ant in the U.K. The research found that the three critical factors in determining the effectiveness of the pre-processing inspection are the complexity of the component geometry including internal ports, the number of sub-components and the number of material employed in the construction of the component. These factors were then used to establish a practical method of assessing the true costs of remanufacturing. The findings were validated at several European Caterpillar Remanufacturing facilities. The beneficiaries of this research are both academia and industry: it adds to the body of remanufacturing knowledge enabling future research to be targeted at operations that materially affect the process and also assists remanufacturers to make their operations more efficient, thus aiding profitability. The novelty of the research is the new knowledge concerning the factors affecting pre-processing inspection together with the limitation of the benefits as well as the information gathered from over two thousand engines in an industrial setting.
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Andrew, James H. « The Boulton & ; Watt water supply engines : their significance in the development of canals and in the evolution of the Watt steam engine ». Thesis, University of Birmingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507936.
Texte intégralRésumé :
James Watt's low lift water supply engines are shown to be a definable group, distinctly different from his better known mine pumping engines. The study of these engines has increased understanding of the evolution of Watt's ideas for improved efficiency. Many of Watt's later designs embodied features developed on his water supply engines. Study of documents concerning low lift engines has allowed the costs and performance of Watt's early engines to be studied in detail. Previous studies have underestimated the costs of earlier designs of engines. It now appears that the costs of Watt engines were comparable with those of Newcomen engines but gave much improved performance. The steam engine business of Boulton & Watt was responsible for half the eighty pumping engines installed on British canals before 1860. This market domination stemmed in part from the Birmingham Canal's close links with Boulton & Watt and their exclusive use of Soho engines until 1850. Pumped water supplies were seldom specified when British canals were built but the subsequent expansion of trade would have been impossible without steam pumping. Other forms of pumping were used for water supplies but steam pumping proved more reliable, more economic and more suited to a transport system whose owners saw themselves as being in the forefront of contemporary transport development.
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Ögren, Lisa. « Producing special-ordered engines : A mapping of the special-order process and the impact of working from home at an engine assembly plant ». Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86990.
Texte intégralRésumé :
This report is presenting a master thesis work in Industrial Design Engineering with a focus on production development at Luleå University of Technology. The thesis work was conducted in the spring term of 2021 at the engine assembly plant of Scania in Södertälje. The project aimed to map the special-order process to create an overview of the process and present improved work patterns. The project also aimed to map the impact of working from home. A special order is an order that is tailored for the customer in a way that is not supported by the standard order system but produced in ordinary production, this is made possible using the S-order process. The background of the project was that the process is among other things, unclear and person dependent and has resulted in stops and unnecessary and costly maneuverers in the production. The project was a pilot study with a focus on the mapping and analysis of the current and future state of the process, limited to the engine assembly, marine and industry engines and with a focus on the local product preparators. Interviews, observations and document studies were the main methods used to map the process. These data collecting methods complemented each other to create an understanding of the situation using a broad range of perspectives. The result of the data collection was then analysed to present the process and the perceptions of the process to find problems and needs. A specification of requirements was used to summarise the results and to be used during concept development. Concepts were developed through a workshop where the participants brainstormed solutions on the found problems and needs. Literature research was conducted about customisation, digital work environment and learning organisation. Research on customisation was used to understand the background and the challenges with it. The digital work environment consisted of the effects of digital work as well as research on how to design and implement a digital work environment. Research on learning organisation was used to support the presented needs and proposed improved work patterns. The mapping of the current state showed that it is a quick process that affects a lot of people who together quickly must assess if and how the orders are and will be possible to deliver. A coordinator at the engine assembly must make sure that the right people are informed and involved meanwhile these people have been shown to lack understanding of the process its responsibilities and activities, resulting in e.g., worry and stress. To improve the process, a proposition was made on focusing on improving the transfer of knowledge and experience, create a common understanding and approach and improve communication and collaboration. Four concepts were presented where the focus was on learning organisation, continuous improvements and based established methods used at the engine assembly.Denna rapport presenterar ett examensarbete i Teknisk design inom produktionsdesign vid Luleå tekniska universitet. Examensarbetet genomfördes under vårterminen 2021 på Scania motormonteringsanläggning i Södertälje. Syftet med arbetet var att kartlägga S-orderprocessen för att skapa en översikt över denna och presentera förbättrade arbetsmönster. Projektet syftade också till att kartlägga effekterna av att arbeta hemifrån. En specialorder är en order som skräddarsys för kunden på ett sätt som inte stöds av det vanliga ordersystemet men som produceras i den vanliga produktionen, detta möjliggörs genom S-orderprocessen. Bakgrunden till projektet var att processen bland annat är oklar och personberoende och har resulterat i stopp och onödiga och kostsamma manövrer i produktionen. Projektet var en förstudie med fokus på kartläggning och analys av processens nuvarande och framtida tillstånd, begränsat till motormonteringen, industri- och marina motorer och med fokus på de lokala produktberedarna.Intervjuer, observationer och dokumentstudier var de centrala metoderna för att kartlägga processen. Dessa datainsamlingsmetoder kompletterade varandra och skapade en förståelse för situationen utifrån ett brett spektrum av perspektiv. Resultatet av datainsamlingen analyserades för att presentera processen och uppfattningarna av denna för att hitta problem och behov. En kravspecifikation användes för att sammanfatta resultaten och för att användas under konceptutveckling. Koncept utvecklades genom en workshop där deltagarna brainstormade lösningar på funna problem och behov.Litteraturforskning genomfördes om kundanpassning, digital arbetsmiljö och lärandeorganisation. Forskning om kundanpassning användes för att förstå bakgrunden och utmaningarna med det. Digital arbetsmiljö bestod av att förstå effekterna av det samt forskning om hur man utformar och implementerar en digital arbetsmiljö. Forskning om lärandeorganisation användes för att stödja de presenterade behoven och föreslagna förbättrade arbetsmönster.Kartläggningen av nuläget visade att det är en snabb process som påverkar många människor som tillsammans snabbt måste bedöma om och hur ordern är och kommer att vara möjliga att leverera. En koordinator vid motormonteringen måste se till att rätt personer är informerade och involverade samtidigt som dessa personer har visat sig sakna förståelse för processen, dess ansvar och aktiviteter, vilket resulterar i bl.a. oro och stress. För att förbättra processen föreslogs att fokusera på att förbättra kunskaps- och erfarenhetsöverföringen, skapa en gemensam förståelse och tillvägagångssätt och förbättra kommunikation och samarbete. Fyra koncept presenterades där fokus var på lärande organisation, kontinuerliga förbättringar och baserade på etablerade metoder som användes vid motormonteringen.
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Carpenter, Nolan A. W. « A study of exergy destruction and methods improving second law efficiency in common production engines using a thorough analysis of engine simulation results ». Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009m/carpenter.pdf.
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