Dissertations / Theses: 'Internal Combustion Engineering'

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Bishop, Robert Phelps. "Combustion efficiency in internal combustion engines." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15164.

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Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaf 26.
by Robert Phelps Bishop.
B.S.

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2

Green, Jeremy James. "Taguchi methods in internal combustion engine optimisation." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52475.

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Thesis (MScEng)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: Statistical experimental design techniques are powerful tools that are often approached with suspicion and apprehension by experimenters. The trend is to avoid any statistically structured and designed experimentation program, and to rather use the traditional method of following ones "gut feel". This approach, more often than not, will supply a satisfactory solution, but there is so much more information availablefor the same amount of effort. This thesis strives to outline the method and application of the Taguchi methodology of experimental design. The Taguchi method is a practical, statistical experimental design technique that does not rely on the designer's knowledge of the complex statistics typicallyneeded to design experimental programs, a fact that tends to exclude design of experiments from the averageengineers' toolbox. The essence of the statistical design of experiments is this: The traditional method of varying one variable at a time and investigating its effect on an output is no longer sufficient. Instead all the input variables are varied at the same time in a structured manner. The output trends resulting from each input variable are then statisticallyextracted from the data in the midst of the variation. Taguchi method achieves this by designing experiments where every level of every input variable occurs an equal number of times with every level of every other input variable. The experimental designs are represented in orthogonal arrays that are chosen and populated by the experimenter by following a simple procedure. Four case studies are worked through in this text and, where possible, compared to the "traditional" approach to the same problem. The case studies show the additional information and time savings availablewith the Taguchi method, as well as clearlyindicating the importance of using a stable system on which to do the experiments. The Taguchi method generated more information in fewer experiments than the traditional approaches as well as allowing analysis of problems too complex to analysewithout a statisticaldesign of the experimentation procedure.
AFRIKAANSE OPSOMMING: Statistiese eksperimentele ontwerptegnieke is besonder kragtige instrumente wat baie keer met agterdog deur ekspermenteerders beheen word. Die neiging is om enige statistiese gestruktureerde and ontwerpte eksperimentele program te vermy, en om liewer die tradisionele metode, wat op 'n mens se intuïsie staatmaak, te gebruik. Hierdie benadering sal baie keer 'n bevredigende oplossing gee, maar daar is veel meer inligting vir dieselfde hoeveelheid inspanning verkrygbaar, wanneer die Taguchimetode gebruik word. Hierdie tesis strewe om die metode en toepassing van die Taguchimetodologie van eksperimentele ontwerp voor te lê. Die Taguchimetode is 'n praktiese statistiese eksperimentele ontwerptegniek .wat nie op die ontwerper se kennis van komplekse statistiek om eksperimentele programme te ontwerp berus nie. Hierdie komplekse statistiek neig ook om eksperimentele ontwerp van die gemiddelde ingenieursvaardigehede uit te sluit. Die kern van statistiese eksperimentele ontwerp is die volgende: Die tradisionele metode van een veranderlike op 'n slag te varieer om die effek op die uitset te ondersoek, is onvoldoende. In plaas daarvan, word al die insetveranderlikes gelyktydig gevarieer in 'n gestruktureered manier. Die neigings van elke veranderlike is dan statisties ontleed van die data ten midde van die variasie van al die ander veranderlikes. Die Taguchimetode bereik die ontwerpte eksperimente deur elke vlak van elke insetveranderlik in 'n gelyke aantal keer met elke vlak van elke ander insetveranderlike te varieer. Hierdie is verteenwoordig deur ortogenale reekse wat gekies en gevul is deur 'n eenvoudige wisselpatroon te volg. Vier gevallestudies is deurgewerk en, waar moontlik, vergelyk met die tradisonele siening van dieselfde probleem. Die gevallestudies wys hoe toereikbaar die additionele inligting in die Taguchimethode toepassings is. Hulle beklemtoon ook die belangrikheid van 'n stabiele sisteem waarop die eksperimente berus. Die Taguchimetode het meer inligting verskaf met minder eksperimente as die tradisionele toenaderings, en ook toegelaat dat die analise van probleme, te kompleks om te analiseer sonder om 'n statistiese ontwerp van eksperimentele prosedure te volg, opgelos kon word.

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Taylor, Oliver. "Improving the performance of internal combustion engines through lubricant engineering." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:4db8f32e-8260-4cff-ad57-08bfa0b9568e.

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Low friction lubricant development provides a worthwhile contribution to vehicle CO₂ emission reduction. Conventional low friction lubricant development focuses on empirical processes using out dated engine technology and old test methods. This strategy is inefficient and restricts the lubricant's potential. A new method proposed in the present research combines tribological simulations with rig, engine and vehicle tests. This approach provides insights undocumented until now. The contribution to CO₂ emission reduction from individual engine components on vehicle drive cycles that include warm-up is predicted using lubricants down to the new SAE 8 viscosity grade. A bearing model is used to design the lubricant's non Newtonian characteristics to achieve friction reduction. An isoviscous lubricant with a viscosity of 4.6 cSt is shown to achieve the minimum friction in the bearing. The research shows that by starting with lubricants having kinematic viscosities higher than this value, it is possible to improve lubricant performance by lowering viscosity index (VI), introducing shear thinning, or reducing the density and pressure viscosity coefficient. Conversely, for lubricants with lower starting viscosities it is shown that higher VI values, more shear-stable lubricants and higher densities and pressure viscosity coefficients are required. The model predicts that high oil film pressures occur in the bearing and cause significant local lubricant viscosity increase (300%), indicating that the lubricant's pressure viscosity behaviour is important here, despite the contact being conformal. Simulation and motored engine testing establishes lubricant behaviour in the piston-to-bore conjunction. This analysis identifies a poor correlation between measured and predicted values at low engine speeds. A rig-on-liner tribometer shows that this error is attributable to a deficiency in the simulation's characterisation of boundary regime friction. An oil pump test determines how a modern variable displacement oil pump (and its control system) responds to lowering viscosity. The hypothesis that low viscosity lubricants cause the parasitic load from this component to increase is disproven using this component-level rig test. Chassis dynamometer testing compares the CO₂ reduction performance of lubricant thermal management systems to the values achieved by reducing the viscosity grade. CO₂ reductions of between 0.4% and 1.0% are identified using a cold-start new European drive cycle (NEDC) with a 5W-30 preheated to 60°C and 90°C respectively. Reductions in CO₂ emissions between 0.4% and 1.2% are found on the NEDC by lowering the oil fill volume from 5.1 L to 2.1 L. For the unmodified case, a 3.7% reduction in CO₂ emissions is reported by reducing the viscosity grade from a 5W 30 to an SAE 8 in the NEDC. The performance of a novel external oil reservoir is simulated to understand its ability to retain oil temperature during the vehicle cool-down procedure. An oil temperature of 65°C at the end of the soak period (following a prior test where the oil was assumed to reach 90°C) is predicted by installing insulation to the reservoir and indicates that a viable method to achieve the CO₂ benefits identified through lubricant preheating tests exists. A full vehicle model combines the outputs from each of these sub-models to predict lubricant performance on the NEDC the new World-wide harmonized light duty test cycle (WLTC). This new approach provides a tool that enables next generation low friction lubricants to be developed. The model predicts that an SAE 8 lubricant can reduce CO2 emissions by 2.8% on the NEDC and 1.9% on the WLTC compared to a 5W-30. A theoretical experiment, where all lubricant related friction was deleted from the simulation, predicts that lubricant-related CO₂ emissions are 8.7% on the NEDC and reduce to 6.3% on the WLTC. These results indicate that the planned adoption of the WLTC in September 2017 reduces the potential contribution to CO₂ emission reduction from lubricants by 28%.

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Sone, Kazuo. "Unsteady simulations of mixing and combustion in internal combustion engines." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/12171.

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Bai, Dongfang Ph D. Massachusetts Institute of Technology. "Modeling piston skirt lubrication in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74901.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 143-147).
Ever-increasing demand for reduction of the undesirable emissions from the internal combustion engines propels broader effort in auto industry to design more fuel efficient engines. One of the major focuses is the reduction of engine mechanical losses, to which the friction of the piston skirt is one important contributor. Yet there lacks a sufficient understanding of the skirt lubrication behavior to effectively optimize the piston skirt system in practice. The ultimate goal of this work is to develop a comprehensive model to advance the predictability of the skirt friction while integrating all the dynamic behavior of the piston secondary motion and the structural deformation of the piston skirt and cylinder liner. Major contributions of this work are analysis of and development of a model for the oil transport and exchange of the piston skirt region and its surroundings. The new oil transport model is composed with two elements. First, the oil scraped into the chamfer region by the oil control ring during a down-stroke is tracked and its accumulation and release to the skirt region are modeled. Second, oil separation and re-attachment are allowed in the skirt region, breaking conventional full-attachment assumption in lubrication studies. The new oil transport model together with hydrodynamic and boundary lubrication model were coupled with piston secondary motion and structural deformation of the piston skirt and cylinder liner. For numerical efficiency and physics clarity, we used different discretization for the lubrication from the structural deformation. The final model is robust and efficient. The discussion of the model results is focused mainly on the oil transport. There exist a general pattern in available oil for skirt lubrication, namely, skirt tends to be starved when it travels at the upper portion of a stroke. Comparison with visualization experiment for oil accumulation patterns show consistency between model prediction and observation. This work represents a major step forward to realistically predicting skirt friction and the influence of all the relevant design and operational parameters. However, oil supply to the region below the piston skirt can largely influence the outcome of the friction prediction and its mechanism is system dependent. Additionally, simple treatment of the oil transport in the current model is merely a first step to modeling the complex fluid problems involved. Improvements of this model based on application and further analysis will make it a more powerful engineering tool to optimize the skirt system to minimize its undesirable outputs.
by Dongfang Bai.
Ph.D.

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Korir, Patrick Kiprotich. "Experimental Study of Internal Injector Deposits In Internal Combustion Engines Using Renewable Fuels." Thesis, KTH, Materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299199.

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The strive to minimize emissions in the automotive industry keeps gaining momentum. Continuous improvement of engine designs and development of more efficient fuel systems in diesel vehicles is a solution to be applauded. More importantly is the growing shift to use of renewable fuels in internal combustion engines. With countries implementing tighter regulations on emissions, and markets have witnessed a rise in the use of biofuels. Subsequently, the fuel quality varies from market to market. Blending of different fuels changes the properties of fuel as solubility of some compounds reduce. Consequently, soft particles which are precipitated in the process have been linked to deposit formation of internal diesel injector deposits (IDIDs). This project aims at investigating IDIDs and possible conditions that enhance their formation in the injector. An injector test rig operating at actual engine pressures (>2000 bars) has been constructed for this purpose. Test fuel for use in the rig is prepared at Scania by introducing soft particles into B10 fuel. Start of the test rig was performed by checking component functionality and pressure test. Due to leakage problem, a redesign of fuel collection cup was done. Evaluation of test fuel was carried to determine the suitability for deposit formation in the injector. Two screening tests were carried to investigate sticky deposit formation using the test fuel. Autoclave test was carried out at temperature of 150 0C over a period of up to four days. Frying pan test was performed to evaluate formation of deposits with increase in temperature between 90 0C to 230 0C. Analysis was carried out using SEM-EDX, GC-MS and FTIR instruments. The test fuel prepared at Scania for replication of deposits in the injector yielded positive results. Sticky deposits formed during the frying pan test evidenced by stretchy and sticky residue on the pan. FTIR analysis showed that the presence of metal carboxylate which is as a result of the metal ion soft particles. Autoclave tests showed formation of brown deposits on the vessel. SEM-EDX analysis of the brown deposits gave great insights on the morphology of the deposit contrasted to the structure of soft particles initially present in the test fuel. Soft particles are small and smeary with a regular shape while the deposits are large, irregular, agglomerated and rough in texture. This is important in understanding the transformation mechanism of soft particles to deposits. A combination of calcium and sodium soft particles in the test fuel showed better ability to form deposits during the autoclave test. GC-MS analysis showed huge decrease in the concentration of soft particles in test fuel after autoclave tests compared to initial test fuel. In conclusion, the test fuel prepared works as expected and thus can be scaled up for running the injector test rig. Additionally, test fuel containing calcium and sodium soft particles have a higher probability to form deposits. Deposits were indeed proven to be metal carboxylates as expected.
Strävan efter att minimera utsläppen inom fordonsindustrin fortsätter att ta fart. Kontinuerlig förbättring av motorkonstruktioner och utveckling av effektivare bränslesystem i dieselfordon är en lösning som bör applåderas. Ännu viktigare är den ökande övergången till användning av förnybara bränslen i förbränningsmotorer. Med länder som inför strängare utsläppsregler har marknaderna sett en ökad användning av biobränslen. Därefter varierar bränslekvaliteten från marknad till marknad. Blandning av olika bränslen förändrar bränslets egenskaper när lösligheten hos vissa föreningar minskar. Följaktligen har mjuka partiklar som fälls ut i processen kopplats till avlagringsbildning av interna dieselinjektoravlagringar (IDID). Detta projekt syftar till att undersöka IDID:s och möjliga förhållanden som förbättrar deras bildande i injektorn. En injektortestrigg som arbetar vid faktiska motortryck (>2000-bar) har konstruerats för detta ändamål. Testbränsle för användning i riggen bereds på Scania genom att mjuka partiklar förs in i B10- bränsle. Testriggens start utfördes genom kontroll av komponentens funktionalitet och trycktest. På grund av läckageproblem gjordes en omdesign av bränsleuppsamlingskoppen. En värdering av testbränslet genomfördes för att fastställa lämpligheten för deponeringsbildning i injektorn. Två screeningtester utfördes för att undersöka klibbig avlagringsbildning med hjälp av testbränslet. Autoklavtest utfördes vid en temperatur av 150 C under en period av upp till fyra dagar. Autoklavtest utfördes för att utvärdera bildandet av avlagringar med temperaturökning mellan 90 0C till 230 C. Analysen utfördes med hjälp av SEM-EDX, GC-MS och FTIR instrument. Testbränslet som förbereddes i Scania för replikering av avlagringar i injektorn gav positiva resultat. Klibbiga avlagringar som bildas under stekpannans test framgår av stretchiga och klibbiga rester på pannan. FTIR-analys visade att förekomsten av metallkarboxylat som är ett resultat av metalljonens mjuka partiklar. Autoklavtester visade bildandet av bruna avlagringar på fartyget. SEM-EDX-analysen av de bruna avlagringarna gav stora insikter om depositionens morfologi i motsats till strukturen hos mjuka partiklar som ursprungligen fanns i testbränslet. Mjuka partiklar är små och utsmetade med en regelbunden form medan avlagringarna är stora, oregelbundna, agglomererade och grova i konsistensen. Detta är viktigt för att förstå omvandlingsmekanismen för mjuka partiklar till avlagringar. En kombination av kalcium- och natriummjuka partiklar i testbränslet visade bättre förmåga att bilda avlagringar under autoklavtestet. GC-MS-analysen visade en enorm minskning av koncentrationen av mjuka partiklar i testbränsle efter autoklavtester jämfört med det ursprungliga testbränslet. Sammanfattningsvis fungerar testbränslet som förväntat och kan därför skalas upp för att driva injektortestriggen. Dessutom har testbränsle som innehåller mjuka kalcium- och natrium partiklar större sannolikhet att bilda avlagringar. Avlagringarna visade sig faktiskt vara metallkarboxylater som förväntat.

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Meng, Zhen Ph D. Massachusetts Institute of Technology. "Modeling of piston pin lubrication in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129019.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020
Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 120-121).
The piston pin joins the piston and the connecting rod to transfer the linear force on the piston to rotate the crankshaft that is the eventual power outlet of the engine. The interfaces between the piston pin and the pin bore as well as the connecting rod small end are one of the most heavily loaded tribo pairs in engines. Piston pin seizure still occurs often in the engine development and the solution often comes from applying expensive coatings. Furthermore, it has been found that the friction loss associated with the pin can be a significant contributor to the total engine mechanical loss. Yet, there lacks a basic understanding of the lubrication behavior of the pin interfaces. This work is aimed to develop a piston pin lubrication model with consideration of all the important mechanical processes. The model predicts the dynamics of the pin and the lubrication of the interfaces between the pin and pin bore as well as small end.
The model couples the dynamics of the pin with the structural deformation of the mating parts, the hydrodynamic and boundary lubrication of all the interfaces, and oil transport. The model is successfully implemented with an efficient and robust numerical solver with the second order accuracy to compute this highly stiff system. The preliminary results applying the model to a gasoline engine show that the boundary lubrication is the predominant contributor to the total friction. As a result, the interface with more asperity contact tends to hold the pin with it. Thus, the pin friction loss is coming from the interface with less contact. Solely from friction reduction point of view, ensuring efficient hydrodynamics lubrication in one interface is sufficient.
Furthermore, as the heavy load is supported in several small areas, mechanical and thermal deformation of all the parts are critical to load distribution, oil transport, and the generation of hydrodynamic and asperity contact pressure, providing the necessity of the elements integrated in the model. This work represents the first step to establishing a more comprehensive engineering model that helps the industry understand the pin lubrication and find cost-effective solutions to overcome the existing challenges.
by Zhen Meng.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering

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Boulanger, Yves. "A microprocessor system for internal combustion engine PV diagram analysis /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61266.

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An internal combustion engine was instrumented in view of developing automatic diagnosis methods based on the analysis of PV diagrams.
The pressure signal is unstable over successive cycles. Consequently, pressure must be averaged over several consecutive cycles to produce valid data.
Due to instrumentation problems the data obtained was insufficient to allow the development of diagnostics. The investigation reported in this work is thus limited to the development of a microprocessor-based system for the acquisition of pressure-volume data on high speed, spark ignition internal combustion engines.
Several instrumentation problems were identified and solutions applied or proposed. The information presented here can form the basis for further research on the original project.

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Luo, Xi. "Study of Periodical Flow Heat Transfer in an Internal Combustion Engine." Thesis, Wayne State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10637206.

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In-cylinder heat transfer is one of the most critical physical behaviors which has a direct influence on engine out emission and thermal efficiency for IC engine. In-cylinder wall temperature has to be precisely controlled to achieve high efficiency and low emission. However, this cannot be done without knowing gas-to-wall heat flux. This study reports on the development of a technique suitable for engine in-cylinder surface temperature measurement, as the traditional method is “hard to reach.” A laser induced phosphorescence technique was used to study in-cylinder wall temperature effects on engine out unburned hydrocarbons during the engine transitional period (warm up). A linear correlation was found between the cylinder wall surface temperature and the unburned hydrocarbons at mediate and high charge densities. At low charge density, no clear correlation was observed because of miss-fire events. A new auto background correction infrared (IR) diagnostic was developed to measure the instantaneous in-cylinder surface temperature at 0.1 CAD resolution. A numerical mechanism was designed to suppress relatively low-frequency background noise and provide an accurate in-cylinder surface temperature measurements with an error of less than 1.4% inside the IC engine. In addition, a proposed optical coating reduced time delay errors by 50% compared to more conventional thermocouple techniques. A new cycle-averaged Re_s number was developed for an IC engine to capture the characteristics of engine flow. Comparison and scaling between different engine flow parameters are available by matching the averaged Re_s number. From experimental results, the engine flow motion was classified as intermittently turbulent, and it is different from the original fully developed turbulent assumption, which has previously been used in almost all engine simulations. The intermittent turbulence could have a great impact on engine heat transfer because of the transitional turbulence effect. Engine 3D CFD model further proves the existence of transitional turbulence flow. A new multi zone heat transfer model is proposed for IC engines only. The model includes pressure work effects and improved heat transfer prediction compared to the standard Law of the wall model.

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Van, Vuuren Christiaan Michael. "Modelling of internal combustion engine intake and exhaust processes." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52343.

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Thesis (MScEng)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: This thesis is concerned with unsteady, one-dimensional flow, which closely mimics those found in the manifolds of internal combustion engines. The physical equations describing problems of this nature are presented and some of the important concepts introduced. These equations and concepts were verified by comparison to published results. The Method of Characteristics (MaC) for unsteady one-dimensional flow with friction and heat transfer was used to analyse the gas flow through the inlet and exhaust systems of an engine. The theoretical derivation of unsteady gas dynamic boundary conditions is presented and the integration with the unsteady pipe flow explained. A simulation flow model was developed to analyse the flow by using the Mae. Thisflow model was then incorporated into an engine simulation program, ESA,to simulate internal combustion engines and to predict the performance of a specific engine. A cam-profile model and an in-cylinder thermodynamic model are used to complete the ESAsoftware. Experimental work was done on a modified Nissan Z24/NA20 engine to evaluate the simulation model. The manifolds of the Nissan Z24/NA20 were modified to isolate one of the cylinders for a proper single cylinder model. More experimental work was done on a Volkswagen 1.6£ 8-valve and a 1.6£ 20-valve engine to obtain performance data on two inlet manifolds developed using the ESAsoftware. Performance data and pressure traces in the inlet manifold of the Nissan Z24/NA20 were recorded for comparison with the ESA software. Good correspondence was found between tested and modelled data and the differences varied between ±5% on engine performance data and pressure wave frequency predictions, and ± 10% on pressure pulse amplitudes.
AFRIKAANSE OPSOMMING: Hierdie tesis handeloor bestendige, eendimensionele vloei, wat die gasvloei in spruitstukke van binnebrandenjins naboots. Die nodige vergelykings wat hierdie tipe probleme beskryf asook van die belangrikste konsepte, word bespreek. Hierdie vergelykings en konsepte is met behulp van gepubliseerde data geverifieer. Die Metode van Karakteristieke (MVK) vir bestendige, eendimensionle vloei met wrywing en warmte oordrag, is gebruik om die gasvloei deur inlaat en uitlaat sisteme van 'n enjin te analiseer. Die teoretiese afleiding van bestendige gasdinamiese randvoorwaardes asook hul integrasie met die bestendige pypvloei, word verduidelik. 'n Simulasie vloeimodel is ontwikkelom die vloei met behulp van die metode van karakteristieke te analiseer. Hierdie vloeimodel is deel van 'n omvattende enjinsimulasie program, ESA. Dit word gebruik om binnebrandenjins te simuleer en enjinwerkverrigting te voorspel. 'n Nokprofielmodel en 'n termodinamiese ontbrandingsmodel word gebruik om die enjinsimulasie program af te rond. Eksperimentele toetse op 'n gemodifiseerde Nissan Z24/NA20 enjin is gebruik om die simulasie model te evalueer. Die spruitstukke van die Nissan Z24/NA20 is aangepas om een van die silinders te isoleer om so 'n geskikte enkelsilindermodel te skep. Verdere eksperimentele toetse is gedoen op Volkswagen 1.6£8- klep en 1.6£ 20-klep enjins. Werkverrigtingsdata is verkry op twee nuwe inlaatspruitstukke wat met behulp van die ESAsagteware ontwerp is. Werkverrigtingsdata en drukverdelingsdata in die inlaatspruitstuk van die Nissan Z24/NA20is aangeteken om te vergelyk met die resultate van die ESAsagteware. Goeie ooreenstemming is verkry tussen toets- en gemoduleerde data. Die verskille varieer tussen ±5% op enjin werkverrigtingsdata en drukpulsfrekwensie voorspellings, en ± 10%op drukpuls-amplitudes.

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Piaszyk, Jakub. "Animal fat (tallow) as fuel for stationary internal combustion engines." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/4135/.

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The main aim of this thesis is to verify the suitability of waste animal fat, obtained from animal by-products in a process called rendering, as a fuel for internal combustion engines. This work is an attempt to provide guidance and minimal requirements for animal fat to be utilised as fuel. The properties of tallow were monitored on a weekly basis throughout a period of one year. Some properties, namely acidity, showed significant variability. Possible reasons causing variable and high acidity are given together with a proposal for an acidity removal method. The available laboratory facilities enabled the verification of changes in fat's viscosity, density, surface tension and lubricity in a range of temperatures. The impact of storage temperature on deterioration in tallow quality was investigated over a period of one month. The available emission control systems have been reviewed and a solution choice has been made, based on legal and economic criteria. A summary of two thousand hours operation of the 800 kW generating set using neat fat is provided. The renewable electricity generation subsidising system in the United Kingdom has been reviewed. A basic feasibility study for the installed generating set was prepared and the highest tallow price at which electricity generation is profitable was determined.

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Wang, Renze S. M. Massachusetts Institute of Technology. "Numerically generating topology of the liner finish in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101853.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 74-77).
Internal combustion (IC) engines are broadly utilized today. The friction caused by piston rings in IC engines contributes around 20% of the mechanical friction losses. The liner finish is the most critical parameter to define the tension and other design parameters of the piston rings for proper sealing. This work is focused on developing numerical approaches to generating liner finishes based on certain values of topology parameters. The generated surface is able to simulate the lubrication and dry contact behaviors of the original surface, so that the method is used to study the effects of various topology parameters on friction losses. First, methods to analyze, generate, test, and compare honed liner surfaces have been developed. The algorithm to analyze the topology parameters of honed surfaces is described. The honed surfaces are numerically generated and compared with the experimental data. Moreover, the topological variables are changed and the corresponding friction behaviors are studied. The relations between topology variables and friction losses are illustrated. We also developed a quantitative relation between two ISO standards describing the honed liner finish, so that the manufacturing industry can use the surface generation method in convenience. Second, attempts were made to simulate the break-in processes for honed liner finish. Measured and numerically generated surfaces are simulated and compared. The friction and pressure behaviors for lightly and heavily worn surfaces are compared with experimental data. Moreover, by tuning the worn parameters, the friction effective mean pressure (FMEP) curve can match the experimental data. Finally, the algorithm to numerically generate thermally sprayed liner finish is described. The hydrodynamic and dry contact friction behaviors for generated surfaces are compared with experimental data. Critical topology parameters are tuned and their effects on friction losses are studied. Moreover, the effects of the pores created by the plasma spraying processes on the lubrication behaviors are simulated.
by Renze Wang.
S.M.

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Cuseo, James M. (James Michael). "Cold start fuel management of port-fuel-injected internal combustion engines." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32380.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 64).
The purpose of this study is to investigate how changes in fueling strategy in the second cycle of engine operation influence the delivered charge fuel mass and engine out hydrocarbon (EOHC) emissions in that and subsequent cycles. Close attention will be paid to cycle-to-cycle interaction of the fueling strategy. It is our intent to see if residual fuel from each cycle has a predicable influence on subsequent cycle's charge mass and EOHC emissions. The fast flame ionization detector is employed to measure both in-cylinder and engine out hydrocarbon concentrations for various cold start strategies. The manufacturer's original fueling strategy is used as a starting point and is compared to a "in-cylinder fuel air ratio (Phi) [approx.] 1" case (a fueling strategy that results in an in-cylinder concentration of approximately stoichiometric for each of the first five cycles) and to a number of cases that are chosen to illustrate cycle-to-cycle mixture preparation dependence on second cycle fueling. Significant cycle-to-cycle dependence is observed with the change in second cycle. A fueling deficit in cycle two has a more pronounce effect on future cycles delivered charge mass than a fueling surplus while a fueling surplus in cycle two has a more pronounce effect on future cycles charge mass than a fueling deficit.
by James M. Cuseo.
S.M.

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14

Smedley, Grant 1978. "Piston ring design for reduced friction in modern internal combustion engines." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27129.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 113-115).
Piston ring friction losses account for approximately 20% of the total mechanical losses in modern internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel consumption and reduced emissions. The goal of this study was to develop low-friction piston ring designs to improve engine efficiency, without adversely affecting oil consumption, blowby, wear, or cost. These are desirable objectives for today's engine manufacturers as they strive to improve engine performance while trying to meet increasingly stringent emissions regulations. Using an existing piston ring friction and lubrication model, the main contributors to friction in modern internal combustion engines were identified as the top ring around top dead center of the compression/expansion strokes and the oil control ring throughout the engine cycle. Model predictions indicated that the top ring friction could be reduced by implementing a skewed barrel profile design or an upward piston groove tilt design, and oil control ring friction could be reduced by decreasing ring tension. An increase in groove wear was predicted to occur with the upward piston groove tilt design, which could be eliminated by the introduction of a positive static twist on the top ring. An increase in oil consumption was predicted to occur with the low-tension oil control ring design, which could be mitigated either by the introduction of a negative static twist on the second ring, or by the implementation of the skewed barrel top ring design. Model predictions indicated that by combining the low-friction designs, a reduction in piston ring pack friction of 30-35% could be achieved, without an increase in blowby, wear, or oil consumption.
(cont.) Experimental results conducted on a full-scale natural gas power generation engine supported the model predictions for the low-tension oil control ring design. The predicted reduction in piston ring friction would translate to a 0.5-1% increase in brake thermal efficiency, which would result in a significant improvement in fuel economy and a substantial reduction in emissions over the life of the engine.
by Grant Smedley.
S.M.

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15

Buchman, Michael Rafael. "A methodology for turbocharging single cylinder four stroke internal combustion engines." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101815.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 95-97).
This thesis presents a method for turbocharging single cylinder four stroke internal combustion engines, a model used to evaluate it, an experimental setup used to test it, and the findings of this experiment. A turbocharged engine has better fuel economy, cost efficiency, and power density than an equivalently sized, naturally aspirated engine. Most multi-cylinder diesel engines are turbocharged for this reason. However, due to the timing mismatch between the exhaust stroke, when the turbocharger is powered, and the intake stroke, when the engine intakes air, turbocharging is not used in commercial single cylinder engines. Single cylinder engines are ubiquitous in developing world off grid power applications such as tractors, generators, and water pumps due to their low cost. Turbocharging these engines could give users a lower cost and more fuel efficient engine. The proposed solution is to add an air capacitor, in the form of a large volume intake manifold, in between the turbocharger compressor and the engine intake to smooth out the flow.
by Michael Rafael Buchman.
S.M.

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16

Mears, Kevin S. "Water distillation using waste engine heat from an internal combustion engine." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36725.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (leaf 36).
To meet the needs of forward deployed soldiers and disaster relief personnel, a mobile water distillation system was designed and tested. This system uses waste engine heat from the exhaust flow of an internal combustion engine to vaporize water for the purpose of removing impurities. The vapor is condensed back down to water in a finned condenser that experiences forced convection. The system pumps heat transfer oil through a 0.61 meter long, cross flow, annulus-type heat exchanger installed over a section of exhaust pipe where the oil experiences a AT of 7°C. The hot heat transfer oil is then piped to a boiler where it releases its heat to the water and returns to the exhaust heat exchanger to be reheated. Testing demonstrated that the system has a heat up time of 30 minutes, and a steady state distillation rate of 2 gallons per hour. In steady state, the system removes and transfers heat from the exhaust at a rate of 4600 Watts.
by Kevin S. Mears.
S.B.

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17

Weiland, Nathan T. "Feasibility Analysis of an Open Cycle Thermoacoustic Engine with Internal Pulse Combustion." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4789.

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Thermoacoustic engines convert thermal energy into acoustic energy with few or no moving parts, thus they require little maintenance, are highly reliable, and are inexpensive to produce. These traits make them attractive for applications in remote or portable power generation, where a linear alternator converts the acoustic power into electric power. Their primary application, however, is in driving thermoacoustic refrigerators, which use acoustic power to provide cooling at potentially cryogenic temperatures, also without moving parts. This dissertation examines the feasibility of a new type of thermoacoustic engine, where mean flow and an internal pulse combustion process replace the hot heat exchanger in a traditional closed cycle thermoacoustic engine, thereby eliminating the heat exchangers cost, inefficiency, and thermal expansion stresses. The theory developed in this work reveals that a large temperature difference must exist between the hot face of the regenerator and the hot combustion products flowing into it, and that much of the convective thermal energy input from the combustion process is converted into conductive and thermoacoustic losses in the regenerator. The development of the Thermoacoustic Pulse Combustion Engine, as described in this study, is designed to recover most of this lost thermal energy by routing the inlet pipes through the regenerator to preheat the combustion reactants. Further, the developed theory shows that the pulse combustion process has the potential to add up to 7% to the engines acoustic power output for an acoustic pressure ratio of 10%, with linearly increasing contributions for increasing acoustic pressure ratios. Computational modeling and optimization of the Thermoacoustic Pulse Combustion Engine yield thermal efficiencies of about 20% for atmospheric mean operating pressures, though higher mean engine pressures increase this efficiency considerably by increasing the acoustic power density relative to the thermal losses. However, permissible mean engine pressures are limited by the need to avoid fouling the regenerator with condensation of water vapor out of the cold combustion products. Despite lower acoustic power densities, the Thermoacoustic Pulse Combustion Engine is shown to be well suited to portable refrigeration and power generation applications, due to its reasonable efficiency and inherent simplicity and compactness.

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Rodríguez, Pascual Daniel. "Internal Combustion Engine Calibration considering the Embedded Systems Sensor Accuracy." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300063.

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In recent years, the increasing economic, environmental and legal demands on internal combustion engines to reduce emissions and fuel consumption are a major challenge. A lot of effort has been put into achieve reliable methods of diagnosis, fault detection and monitoring to increase safety and efficiency in vehicles. A sensor that is not accurate can affect the overall performance of the system. Therefore, a method able to guarantee that the sensors are providing nominal measurements is required. In the process of engine calibration in the test cell intervene two types of sensors, the laboratory sensors that are the ones that belong to the test cell and provide accurate measurements, and the production sensors that are the ones mounted in the engines during normal operation of the vehicles and do not provide as much accurate measurements as the laboratory sensors. The aim of the project is to develop a method able to ensure that the production sensors are providing the correct measurements according to the physical input property. For this purpose, the laboratory sensors were used as reference measurements. The method was divided into automated calibration and manual calibration. The main difference was that the manual calibration requires more intervention of the engineer in charge of the test cell to place extra sensors. In truck industry, the control of emissions (CO, NOx, HC and PM) has been done mainly through SCR catalysts, DOCs and DPFs. The measurements provided by the sensors on which the correct functioning of these systems depends are therefore of vital importance. That is why this Thesis was focused on the performance of the back-pressure sensor located in the exhaust manifold upstream the turbine; the High Temperature Sensor with its three probes positioned in different points of the aftertreatment system and the NOx sensor located at the aftertreatment too. They were compared with their corresponding laboratory sensor. In the proposed method, the gain and the offset are calculated, and comparing them with the supplier specifications, it was possible to determine if the sensor is in the need for calibration or not. Then, modifications would have to be conducted in their parameters stored in the ECUCombustion Engine Calibration considering the Embedded Systems Sensor Accuracyin order to get nominal values. In order to develop the method, previous tests were studied performed in the company, and the implementation of the method was done with actual tests. The final test performed with the parameters modifications has revealed that all the gain and offset values for the sensors analyzed improved their performance, providing values closer to their ideal behavior. However, the final results still lie outside the acceptance threshold. Theoretically, if this method is repeated with further tests, the parameters would continue improving, staying inside the threshold. Therefore, it is in the need of further implementation and verification to be considered completely validated in order to achieve that the sensors remain within specifications during several tests.
Under de senaste åren har de ökande ekonomiska, miljömässiga och rättsliga kraven på förbränningsmotorer för att minska utsläppen och bränsleförbrukningen varit en stor utmaning. Mycket arbete har lagts ned på att uppnå tillförlitliga metoder för diagnos, feldetektering och övervakning för att öka säkerheten och effektiviteten i fordon. En sensor som inte är korrekt kan påverka systemets totala prestanda. Därför behövs en metod som kan garantera att sensorerna ger nominella mätningar. Vid kalibrering av motorer i testcellen används två typer av sensorer, laboratoriesensorer som tillhör testcellen och som ger exakta mätningar, och produktionssensorer som monteras i motorerna under normal drift av fordonen och som inte ger lika exakta mätningar som laboratoriesensorerna. Syftet med projektet är att utveckla en metod som kan säkerställa att produktionssensorerna ger korrekta mätningar i enlighet med den fysiska ingående egenskapen. För detta ändamål användes laboratoriesensorerna som referensmätningar. Metoden delades upp i automatisk kalibrering och manuell kalibrering. Den största skillnaden var att den manuella kalibreringen kräver mer ingripande av den ingenjör som ansvarar för testcellen för att placera ut extra sensorer. Inom lastbilsindustrin har kontrollen av utsläpp (CO, NOx, HC och PM) huvudsakligen skett med hjälp av SCR-katalysatorer, DOC:er och DPF:er. De mätningar som tillhandahålls av de sensorer som krävs för att dessa system skall fungera korrekt är därför av avgörande betydelse. Det är därför som denna avhandling fokuserar på prestandan hos mottryckssensorn som är placerad i avgasröret uppströms turbinen, högtemperatursensorn med sina tre sonder som är placerade på olika ställen i efterbehandlingssystemet och NOx-sensorn som är placerad vid efterbehandlingen. De jämfördes med motsvarande laboratoriesensor. I den föreslagna metoden beräknas förstärkningen och förskjutningen, och genom att jämföra dem med leverantörens specifikationer var det möjligt att avgöra om sensorn behöver kalibrerasCombustion Engine Calibration considering the Embedded Systems Sensor AccuracyDaniel Rodriguez Pascualeller inte. I så fall måste ändringar göras i de parametrar som lagras i ECU:n för att få nominella värden. För att utveckla metoden studerades tidigare tester som utförts i företaget, och genomförandet av metoden skedde med faktiska tester. Det slutliga testet som utfördes med ändringarna av parametrarna visade att alla förstärknings- och förskjutningsvärden för de analyserade sensorerna förbättrade deras prestanda och gav värden som låg närmare deras ideala beteende. De slutliga resultaten ligger dock fortfarande utanför acceptansgränsen. Teoretiskt sett skulle parametrarna fortsätta att förbättras och ligga inom tröskelvärdet om denna metod upprepas med ytterligare tester. Därför behövs ytterligare genomförande och verifiering för att den ska anses vara helt validerad så att sensorerna håller sig inom specifikationerna under flera tester.

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19

Williams, Paul Ngcebo Tudor. "Modeling of internal combustion engine thermodynamics, valve dynamics and valve flow." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52939.

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Thesis (MScEng)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: In the design or modification of internal combustion (IC) engine components, the South African Automotive industry has always relied on either design by mother companies or quasi-empirical design methods. These methods have restricted the performance and reliability of local designs. A personal computer based model of four stroke engine operation has been developed as a rapid and cost-effective aid to users who wish to determine the performance of an engine with reasonable accuracy before dynamometer testing is possible. This model consists of a thermodynamic model of combustion and gas exchange linked to a manifold flow model. Accompanying this is a simulation of valve flow and a cam dynamic model, enabling full assessment of the optimum cam profiles and valve angles for various automotive engine configurations. The accuracy of these models has been verified by comparison with a set of engine dynamometer tests. The models have also been used with great success in local and international development projects in conjunction with local automotive manufacturers. In particular, two engine upgrade projects have been successfully completed, in which the program was used to aid the design of inlet manifolds, the selection of camshafts, and the selection of compression ratios.
AFRIKAANSE OPSOMMING: In die ontwerp of modifikasie van binnebrandenjin-komponente het die Suid-Afrikaanse Motorbedryf gewoonlik staatgemaak op óf die ontwerpe van die moedermaatskappy óf is van quasi-empiriese ontwerp metodes gebruik gemaak. Hierdie metodes het die werkverrigting en uithouvermoë van plaaslike ontwerpe beperk. 'n Rekenaar model wat die werking van 'n vierslagenjin moduleer, is ontwikkel as 'n vinnige en koste effektiewe hulpmiddel vir ontwerpers om 'n redelike akkurate voorspelling van enjin werkverrigting te verkry, voordat dynamomotor toetswerk moontlik is. Die model bestaan uit 'n termodinamise model vir ontbranding en die gas uitruilproses, gekoppel aan 'n spruitstuk vloeimodel. Die model word saam met 'n simulasie van klepvloei en 'n nok dinamiese model gebruik, wat toelaat dat 'n goeie raming van die optimum nokprofiele en klephoeke gemaak kan word vir verskeie automobielenjin konfigurasies. Die akuraatheid van hierdie modelle is bevestig deur die vergelyking van simulasie resultate met 'n omvangreike stel enjin dynamomotor toetse. Die modelle is ook met groot sukses in verskeie plaaslike en internasionale ontwikkelingsprojekte, in samewerking met die plaaslike motorbedryf, gebruik. In besonder is twee enjinontwikkelingsprojekte suksesvol voltooi, waarin die simulasie program gebruik is om die ontwerp van die inlaat spruitstuk, die keuse van nokasse en die keuse van drukverhouding te vergemaklik.

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20

Bhouri, Mohamed Aziz. "Curved beam based model for piston-ring designs in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/111772.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 169-173).
Characterizing the piston ring behavior is inherently associated with the oil consumption, friction, wear and blow-by in internal combustion engines. This behavior varies along the ring's circumference and determining these variations is of utmost importance for developing ring-packs achieving desired performances in terms of sealing and conformability. This study based on straight beam model was already developed but does not consider the lubrication sub-models, the tip gap effects and the characterization of the ring free shape based on any final closed shape. In this work, three numerical curved beam based models were developed to study the performance of the piston ring-pack. The conformability model was developed to characterize the behavior of the ring within the engine. In this model, the curved beam model is adopted with considering ring-bore and ring-groove interactions. This interactions include asperity and lubrication forces. Besides, gas forces are included to the model along with the inertia and initial ring tangential load. In this model we also allow for bore, groove upper and lower flanks thermal distortion. We also take into account the thermal expansion effect of the ring and the temperature gradient from inner diameter (ID) to outer diameter (OD) effects. The piston secondary motion and the variation of oil viscosity on the liner with its temperature in addition to the existence of fuel and the different hydrodynamic cases (Partially and fully flooded cases) are considered as well. This model revealed the ring position relative to the groove depending on the friction, inertia and gas pressures. It also characterizes the effect of non-uniform oil distribution on the liner and groove flanks. Finally, the ring gap position within a distorted bore also reveals the sealing performance of the ring. Using the curved beam model we also developed a module determining the twist calculation under fix ID or OD constraint. The static twist is an experimental characterization of the ring during which the user taps on the ring till there is a minimum clearance between the ring lowest point and the lower plate all over the ring's circumference but without any force contact. Our last model includes four sub-models that relate the ring free shape, its final shape when subjected to a constant radial pressure (this final shape is called ovality) and the force distribution in circular bore. Knowing one of these distribution, this model determines the other two. This tool is useful in the sense that the characterization of the ring is carried out by measuring its ovality which is more accurate than measuring its free shape or force distribution in circular bore. Thus, having a model that takes the ovality as an input is more convenient and useful based on the experiments carried out to characterize the ring.
by Mohamed Aziz Bhouri.
S.M.

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21

Tian, Tian. "Modeling the performance of the piston ring-pack in internal combustion engines." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10445.

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22

Bhouri, Mohamed Aziz. "Curved beam based model for piston-ring designs in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111772.

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Abstract:

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 169-173).
Characterizing the piston ring behavior is inherently associated with the oil consumption, friction, wear and blow-by in internal combustion engines. This behavior varies along the ring's circumference and determining these variations is of utmost importance for developing ring-packs achieving desired performances in terms of sealing and conformability. This study based on straight beam model was already developed but does not consider the lubrication sub-models, the tip gap effects and the characterization of the ring free shape based on any final closed shape. In this work, three numerical curved beam based models were developed to study the performance of the piston ring-pack. The conformability model was developed to characterize the behavior of the ring within the engine. In this model, the curved beam model is adopted with considering ring-bore and ring-groove interactions. This interactions include asperity and lubrication forces. Besides, gas forces are included to the model along with the inertia and initial ring tangential load. In this model we also allow for bore, groove upper and lower flanks thermal distortion. We also take into account the thermal expansion effect of the ring and the temperature gradient from inner diameter (ID) to outer diameter (OD) effects. The piston secondary motion and the variation of oil viscosity on the liner with its temperature in addition to the existence of fuel and the different hydrodynamic cases (Partially and fully flooded cases) are considered as well. This model revealed the ring position relative to the groove depending on the friction, inertia and gas pressures. It also characterizes the effect of non-uniform oil distribution on the liner and groove flanks. Finally, the ring gap position within a distorted bore also reveals the sealing performance of the ring. Using the curved beam model we also developed a module determining the twist calculation under fix ID or OD constraint. The static twist is an experimental characterization of the ring during which the user taps on the ring till there is a minimum clearance between the ring lowest point and the lower plate all over the ring's circumference but without any force contact. Our last model includes four sub-models that relate the ring free shape, its final shape when subjected to a constant radial pressure (this final shape is called ovality) and the force distribution in circular bore. Knowing one of these distribution, this model determines the other two. This tool is useful in the sense that the characterization of the ring is carried out by measuring its ovality which is more accurate than measuring its free shape or force distribution in circular bore. Thus, having a model that takes the ovality as an input is more convenient and useful based on the experiments carried out to characterize the ring.
by Mohamed Aziz Bhouri.
S.M.

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23

Herrera, Carlos A. (Carlos Alberto) 1974. "Hybrid internal combustion engine : driving a vehicle using air compressed in braking." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47662.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.
Includes bibliographical references (p. 79-80).
After the oil crisis of the 1970's, stringent government standards placed on automobile manufacturers have led the industry to explore more fuel efficient alternatives to the vehicle with a conventional internal combustion engine/transmission powertrain. This is the motivation behind Mr. David F. Moyer's hybrid internal combustion engine concept. A vehicle using this engine should attain higher fuel economy levels as a result of kinetic energy recovery and reuse (achieved by using the engine as an air compressor during braking, storing the compressed air, and then utilizing that air to turn the engine and drive the vehicle), cylinder disabling, and the elimination of idling losses. Data of transmission input power for Ford Motor Company's P2000 vehicle while driven through 1373 seconds of typical urban driving (CVS cycle) were used, combined with a model to estimate engine friction, to carry out an available energy analysis of the hybrid engine. An air processing efficiency was incorporated into the analysis to determine how irreversible the air storage/use processes were. Fuel economy was estimated for the different operating conditions of the concept by matching Ford's 1.8-litre Zetec engine to the vehicle and using the fuel consumption map for that engine. The vehicle with the baseline engine yields 32.6 mpg. Adding cylinder disabling raises this value to 36.8 mpg. Ultimately, if reversible hybrid operation is added, the best possible fuel economy this concept can achieve is 52.4 mpg, for a total maximum savings of 38% in fuel consumption. Using simple thermodynamic models of a braking and an air driving event, we predicted maximum values of 85% and 88% for the air processing efficiency in the braking and the air driving case, respectively. An overall value of 65% was chosen for the efficiency, resulting in a maximum fuel economy of 48.1 mpg and fuel savings of 32%. The analysis above led us to conclude that engine friction plays a significant role in reducing the benefit of this hybrid concept. Furthermore, fully variable valve timing and cylinder disabling improve fuel economy for a conventional engine significantly, and they are essential in minimizing the thermodynamic losses involved in hybrid operation. Therefore, we recommend that methods to reduce engine friction as well as means to implement fully variable valve timing modifications to an internal combustion engine be explored further.
by Carlos A. Herrera.
S.M.

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24

Audette, William E. "Estimation of oil consumption due to in-cylinder vaproization in internal combustion engines." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/46261.

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McNally, Conor P. (Conor Peter) 1975. "Development of a numerical model of piston secondary motion for internal combustion engines." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/26880.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.
Includes bibliographical references (leaves 100-101).
The reciprocating motion of the piston of an internal combustion engine in the vertical plane is referred to as its primary motion, and it is this primary motion that produces power in the engine. Due to the fact that there is a clearance between the piston and the liner, and that certain forces on the piston have components in the horizontal direction, there exists some lateral motion of the piston and also some rotational motion about the wrist pin axis. This motion is referred to as secondary motion. Secondary motion has significant implications for oil transport past the piston ring-pack, engine friction and engine noise. For these reasons a comprehensive numerical model of secondary motion is a valuable tool for engine designers and development engineers. This work involves the development of a comprehensive and robust computer model of piston secondary motion, which can be easily run on a desktop computer. The model is applicable to both conventional mono-piston assemblies and also to articulated piston assemblies. The modeling approach involves treating the piston assembly as a set of independent rigid bodies, and formulating and solving the equations of motion for each body. The hydrodynamic skirt-liner interaction force is computed by solving the Reynolds equation for the oil film and integrating the computed pressure. This essentially one dimensional calculation is performed at several circumferential locations on the piston, and the results are integrated to yield a single force in the main thrust-anti thrust direction. The model is first developed with a basic form of this hydrodynamic calculation, which is later improved to include a solution for the wetted region and a complete pressure distribution on the piston. Results using both forms of the model are compared and analyzed, and the final model is used to perform several parametric studies involving various engine operating parameters.
by Conor P. McNally.
S.M.

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26

McClure, Fiona. "Numerical modeling of piston secondary motion and skirt lubrication in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42289.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.
Includes bibliographical references (p. 239-241).
Internal combustion engines dominate transportation of people and goods, contributing significantly to air pollution, and requiring large amounts of fossil fuels. With increasing public concern about the environment and the reliability of oil supplies, automotive companies are pushed to improve engine design in order to reduce engine emissions and fuel consumption. This project aims to develop a numerical model of piston dynamics and lubrication in internal combustion engines, enabling prediction of friction generation at the piston -cylinder bore interface, and oil transport in the power cylinder system. It is currently estimated that the piston - cylinder bore friction accounts for up to 25% of the power loss in a typical engine, while oil transported to the combustion chamber by the piston and ring-pack contributes significantly to engine emissions. A dry piston model was first developed to allow fast calculation of approximate piston dynamics. An elastohydrodynamic lubrication model was then developed to allow direct numerical simulation of the effect of piston tooling marks, and comparison with results obtained using an Average Reynolds equation with flow factors. The lubrication model was incorporated into the piston dynamics model, enabling more accurate evaluation of friction and oil transport. Comparison between the dry and lubricated model results demonstrate the effect of oil film thickness on piston lateral motion, tilt, friction generation and oil transport.
by Fiona McClure.
Ph.D.

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27

Dawson, Jonathan Adam. "An experimental and computational study of internal combustion engine modeling for controls oriented research /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487949836206508.

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28

Vasilakos, I. "Cavitation in the cylinder-liner and piston-ring interaction in internal combustion engines." Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/19265/.

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The emissions control regulations introduced by governments are set to improve the quality of the engines and reduce the impact automobiles have on the planet. The regulations imposed on the manufactures have proven very difficult to meet, with some of the leading names in the industry investing significant part of their funding in research and development. Their goal is to reduce the fuel consumption and exhaust emissions while increasing the engine performance and durability. The piston-ring and cylinder-liner interaction is the major source of frictional losses for reciprocating internal combustion engines. The failure of the piston-rings to effectively control the transportation of oil from the sump onto the cylinder walls results among others to lubricant consumption. The objective of this project is to assist with the investigation of phenomena that occur in the cylinder liner and piston ring interaction under different operating conditions. To achieve these the following investigations have been carried, flow and cavitation visualisation in a model lubricant rig, and cavitation visualisation in a newly designed optical engine. The main focus of the project was the design, manufacturing and assembly of an optical internal combustion reciprocating engine. The new engine has been based on the design of a 450cc Ricardo Hydra, where many parts had to be redesigned or modified. The engine was fitted with a custom cylinder liner designed to accommodate custom made windows that covers almost the full length of the liner over a width of 25mm; this visibility allows access not only into the contact point over the entire length of the liner, but also provides access to the combustion chamber to allow for flow visualisation and flow field measurements. The cooling system was modified to allow for the accurate control and maintaining of the engine temperature. The control of the engine is performed with a new custom engine management system build in LabView which allowed for the precise control of the engine and of all the auxiliary systems such as fuel, ignition, sensors and optical equipment. The new control system and the optical engine were tested successfully up to 3000 RPM with the same specification as the unmodified engine in terms of in cylinder pressure and maintaining the original engine tolerances. The design of the new optical engine was a great success and it would offer a useful and valuable testing device that would allow further investigation to be carried out. In parallel to the design of the engine, a parametric experimental study was undertaken and performed on 6 lubricant samples of different formulations at two lubricant flow rate of 0.02 and 0.05 L/min, three speeds at 100, 300 and 600 RPM, and two different temperatures at 30oC and 70oC. The study was performed on an existing test-rig to visualise lubricants cavitation using two high speed cameras coupled with three ARRI high intensity light sources. This optical test device is a quick, efficient and effective way to test different lubricant samples and compare their in-between performance. The captured video images were processed through a custom build algorithm designed around the lubrication rig. This algorithm allowed for the extraction of matrices such as cavity length, cavity width, area of cavitation and number of cavities present in the area between the piston ring and the cylinder liner interaction. This parametric study offered a set of valuable results from which the performance of each lubricant can be assessed and a direct link between the lubricant formulation and the operating conditions can be established. Cavitation visualisation of the lubricant in the new optical engine was performed under motorised and firing condition up to an engine speed of 300 RPM and produced high quality images from the usually inaccessible piston ring and cylinder liner interaction. This unique design allowed to investigate a number of phenomena around that specific area like cavitation, blow-by, fuel spray, flame propagation and oil transportation. The parametric study results investigated in the test-rig have been linked with those obtained in the conventional internal combustion engines while providing a very useful and very powerful piece of software.

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Luh, Guan-Chun. "Identification of an internal combustion engine model by nonlinear multi-input multi-output system identification /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487853913100998.

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30

Homann, Gregor. "Preconditioning measurement and control system for a combustion engine in a vehicle." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/d1010998.

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Modern vehicles have to ful ll new CO2 emission and additionally customer comfort requirements to stay competitive. A major impact to the fuel consumption of an internal combustion engine (ICE) has the starting period. An ICE equipped with a preconditioning system which heats up the ICE much faster than a common ICE. This procedure of preconditioning is called peak heating. The main benet of preconditioning of an ICE is less fuel consumption. Recently the only way to obtain a fast heating up of an ICE is the injection of a higher amount of fuel during the starting period. This heat up procedure can be changed if a heat reservoir is available to the ICE during the starting period. In this case the additional injection of fuel is redundant and therefore the consumption during the starting period can be reduced. The major advantages of this strategy are achieved in cold ambient conditions. During this project di erent preconditioning strategies and di erent points of interaction in the coolant circuit of an ICE have been investigated. The preconditioning concepts have been evaluated according to their heating up performance and their implementation into the engine compartment. The results obtained by this project highlight that a system layout which enables a preheating of the cylinder block by a heat reservoir located in a bypass-line to the heater core is the most e ective point of interaction. The best results have been achieved with a coolant ow of 10 l/min at a temperature of 90 C. Furthermore, this project points out that the implementation of a preconditioning system into the oil cooler will achieve similar results. This strategy of preconditioning the engine oil reduces the internal frictions of the ICE which leads to a decreasing consumption. This solution is much more energy e cient and technically easier to implement into a modern vehicle with its limited space. An additional side e ect of the preconditioning of the oil is a longer service life of the ICE.

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Van, der Westhuizen H. J. "Computational and experimental investigation of chamber design and combustion process interaction in a spark ignition engine." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53334.

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Thesis (MScEng)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: The automotive industry in South Africa is expanding as a result of pressure on the world economy that forces vehicle manufacturers to outsouree work to developing countries. In order to add value to automotive engine development, the capability to perform state-of-the-art engineering must be developed in this country. Threedimensional fluid flow simulation is one such area and is being developed in this study in order to enhance the ability to develop combustion systems. Another capability being developed at the University of Stellenbosch is the simulation of valve train dynamics. It was realised that there is a lack of research results of in-cylinder flow characteristics and how they influence combustion chamber processes. This project focuses on the investigation of two different combustion chamber geometries and how they influence the flow and combustion processes in two different combustion chambers. The aim is to gain a better understanding of combustion chamber flow as an indirect result from comparing the flow in two fundamentally different engines under similar operating conditions. The difference in the engines is that one was developed for reduced exhaust gas emissions while the other was developed to achieve high performance. The numerical simulation capability is developed in the process of achieving this goal. To achieve the above-mentioned aim, a literature study was performed on the different combustion chamber flow characteristics and how they are influenced by different configurations. An experimental method of measuring combustion characteristics is studied in order to establish the ability to perform the latter. Theory of numerical flow simulation is also studied with this same goal in mind. Experimental testing is performed and combustion analysis is done on the results. In conjunction to the experimental work, numerical flow simulations are performed on the two different combustion chambers. The results from experimental testing and numerical simulations have shown that obstructions in the flow into the combustion chamber, together with a port configuration that cause flow around the longitudinal axis of the cylinder, increases the rate at which fuel burns in the combustion chamber and thereby reduce the production of toxic emissions from the engine. The study also proved that reducing resistance to flow increases the amount of air that is breathed by the engine and thereby results in increased torque generation. Through this study, opportunities for further research are identified. The results of the study can be used when new combustion systems are developed, especially in the light of ongoing tightening of emission regulations. The contribution to numerical flow simulation capabilities developed in this study add value to the ability to develop new combustion systems in the future, especially when complimented by some of the further research topics identified.
AFRIKAANSE OPSOMMING: Die motorbedryf in Suid-Afrika is besig om vinnig te ontwikkel as direkte gevolg van druk op die wêreldekonomie wat internasionale motorvervaardigers forseer om werk na ontwikkelende lande uit te kontrakteer. Hoogs gesofistikeerde ingenieurstegnieke moet ontwikkel word in Suid-Afrika met die doelom waarde toe te voeg aan enjin ontwikkeling. Drie-dimensionele vloei simulasie is een van hierdie vermoëns en word tydens hierdie studie ontwikkelom die verbrandingstelsel ontwikkelings-vaardighede te bevorder. Nog 'n vaardigheid wat tans ontwikkel word aan die Universiteit van Stellenbosch is die vermoë om nok-en-klepstelsel dinamika te simuleer. Daar bestaan egter 'n leemte in navorsingsresultate van vloei eienskappe binne in die verbrandingsruim en hoe dit verbrandingsruim prosesse beïnvloed. Die projek fokus dus op 'n ondersoek van twee verskillende geometriese konfigurasies van die verbrandingsruim en hoe dit die vloei- en verbrandingsprosesse in die twee konfigurasies beïnvloed. Die doel is om 'n beter begrip te ontwikkel van verbrandingsruim prosesse as 'n indirekte gevolg van die vergelyking tussen twee fundamenteel verskillende enjins onder eenderse bedryfstoestande. Die verkil tussen die twee enjins is dat een ontwikkel is met die doelop verlaagde uitlaatgas emmissies en die ander ontwikkel is om verbeterde werkverrigting. Die numeriese simulasie vermoë is ontwikkel in die proses om die doel te bereik. Om bogenoemde doel te bereik is 'n literatuurstudie gedoen wat verskillende vloeieienskappe in die verbrandingsruim ondersoek, asook hoe dit deur verskillende konfigurasies beïnvloed word. 'n Eksperimentele metode III die bepaling van verbrandingseienskappe is ook bestudeer met die doelom laasgenoemde uit te voer. Teorie aangaande numeriese vloei simulasie is ook bestudeer met bogenoemde doel. Eksperimentele toetse is gedoen en verbrandingsanalise uitgevoer op die resultate. In kombinasie met die eksperimentale werk is numeriese simulasies van die prosesse in die twee verbrandingsruim konfigurasies uitgevoer. Die resultate van die eksperimentele toetse en numeriese simulasies toon dat obstruksies in die vloei na die verbrandingsruim, gesamentlik met die poort konfigurasie wat veroorsaak dat lug om die longitudinale as van die silinder vloei, die tempo waarteen die lug-brandstof mengsel verbrand verhoog en sodoende die vrystelling van skadelike uitlaatgasse na die atmosfeer verminder. Die studie het ook getoon dat die vermindering van weerstand teen vloei, die hoeveelheid lug wat in die verbrandingsruim invloei vermeerder en sodoende die wringkrag wat deur die enjin gelewer word verhoog. Deur die studie is verdere navorsingsgeleenthede uitgewys. Die resultate van die studie kan gebruik word in die ontwikkeling van nuwe verbrandingstelsels, veral in die lig van verstrengende regulasies rakende uitlaatgas emmissies. Die bydrae tot numeriese vloei simulasie vermoëns ontwikkel in hierdie studie voeg waarde toe tot die vermoë om nuwe verbrandingstelsels te ontwikkel, veral wanneer dit gekomplimenteer word met van die verdere navorsingsonderwerpe wat geïdentifiseer is.

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32

Takata, Rosalind (Rosalind Kazuko) 1978. "Effects of lubricant viscosity and surface texturing on ring-pack performance in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35644.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (p. 117-120).
The piston ring-pack contributes approximately 25% of the mechanical losses in an internal combustion engine. Both lubricant viscosity and surface texturing were investigated in an effort to reduce this ring-pack friction and increase engine efficiency. While both optimizing viscosity and surface texturing are predicted to cause a reduction in ring/liner friction individually, a combined approach may cause an even greater friction reduction while mitigating unwanted side-effects such as oil consumption and wear. Existing MIT models, with some modifications and supplementary programs to allow investigation of the parameters of interest, were used to conduct this research. A ring-pack model based on average flow-factor Reynolds analysis was used for both studies, with a modified form of this program, along with a supplementary deterministic model for surface analysis, used for the study of surface texturing. Although these advanced models are applicable in a wide range of cases, the surface textures studied in this research are very different than a typical cylinder liner surface, and can be represented only approximately by the averaged Reynolds analysis upon which the ring simulation is based.
(cont.) For this reason, the analysis of surface features has focused on a parametric study, whose goal is to analyze trends relating ring/liner friction to surface parameters, and to make a general evaluation of the potential of surface texturing to reduce ring-pack losses. Study of lubricant viscosity effects throughout the engine cycle indicated that conditions in the mid-stroke region have the main influence (compared to the end-strokes) on friction power losses, and that reducing viscosity here could lead to a reduction in ring-pack FMEP of -7%. Changes in cylinder liner surface texturing, also, can lead to significant friction reductions. Patterns of both grooves and round dimples were shown to reduce ring/liner friction by increasing hydrodynamic pressure in the lubricant, thus increasing oil film thickness and reducing both asperity contact and hydrodynamic friction. Also, because the effect of reducing viscosity is to decrease oil film thickness, and that of the surface texturing considered is to increase it, these two parameters can be optimized together, and balanced so that oil film thickness remains constant. Then, negative side-effects such as wear (due to decrease in film thickness) and oil consumption (resulting from an increase in film thickness) can be negated, even as friction is reduced even further than is possible using viscosity or surface effects alone.
by Rosalind Takata.
S.M.

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33

Fang, Tianshi. "Computations and modeling of oil transport between piston lands and liner in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92143.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 135-136).
The consumption of lubricating oil in internal combustion engines is a continuous interest for engine developers and remains to be one of the least understood areas. A better understanding on oil transport is critical to an optimization of engine designs, and advanced analytical tools are essential to the achievement of reduced frictions without compromising oil consumption. Oil transport from piston lands to a liner, hereafter called "bridging", has been observed in engine tests. The additional oil transferred to the liner becomes a potential source of oil consumption through ring-liner interaction. Thus, it is important to develop more quantitative models to better analyze bridging. The objective of this work is to obtain a more in-depth understanding on the oil transport between piston lands and liner and provide quantitative models of the oil transport mechanisms. Multiphase Computational Fluid Dynamics (CFD) was employed together with analyses of experimental observations. Three categories of bridging were identified: assisted bridging, self-sustained bridging, and reverse bridging. While assisted bridging involves an axial oil flow across an entire piston land, the other two phenomena are localized and become prominent at low engine speeds. The mechanisms of each phenomenon were analyzed in this work. Correlations and theoretical models were developed to associate the risk of bridging with geometrical designs of a piston and operating conditions of an engine. Particularly, the theoretical model of self-sustained bridging contributes to the optimization of geometrical designs of the third land of a piston ring pack. This work constitutes a major step towards a further quantification of oil transport. Some findings and models presented in this work can readily contribute to providing optimal solutions to certain piston regions. Furthermore, the results of this work serve broader purposes in providing boundary conditions to other interactions in a piston ring pack.
by Tianshi Fang.
S.M.

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Dearlove, Janice Vivienne. "Apparatus for simultaneous measurement of internal combustion engine ring/liner oil film thickness and friction." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36942.

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Stewart, Marcus Clayton. "Design and analysis of a variable-compression, ratio internal-combustion engine : the Alvar engine concept." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43419.

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Tailony, Rauf. "Internal Combustion Engine Cold Test Driveline Modeling, Analysis and Development." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1564765172535669.

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37

Sezer, Ahmet. "Experimental Investigation Of An Oil Loss Mechanism In Internal Combustion Engines." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611954/index.pdf.

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Oil loss mechanisms in internal combustion engines have been subject to many researches. By the help of technological developments effects of several problems due to oil losses were examined and tried to be reduced. Environmental pollution and performance loss are important issues that oil consumption in internal combustion engines contribute. In this study the effects of individual parameters on the oil accumulation in 2nd land crevice of internal combustion engines, volume between top compression rings, were investigated. The study aimed to investigate the effects of oil film thickness and oil film temperature on the oil accumulation in the 2nd land which contributes to one of the mechanisms of oil consumption in internal combustion engines. Controlled experiments were performed on a modeled piston cylinder assembly. It was seen that oil accumulated in the 2nd land crevice by blow-by gases was affected by the film thickness of lubricating oil and the temperature of the lubricating oil. The amount of oil accumulated increased with increasing oil film thickness. The results also showed that below oil film thickness of 45 &
#956
m
amount of oil accumulated increased with the increase of oil temperature.

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38

Camm, Joseph. "Mixture preparation and injection strategy in direct injection spark ignition engines." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:eb2e1d11-39fc-4a3f-a0ba-c607c4034afb.

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The mixture preparation process in a Direct Injection Spark Ignition (DISI) engine has a strong influence on the processes that follow it, including combustion and the formation of pollutant emissions. The formation of particulate matter during DISI engine combustion is a complex phenomenon that has proven difficult to predict. Vehicle tailpipe emissions are subject to increasingly stringent particulate matter emissions worldwide; in Europe, particulate number emission limits came into force in 2014 and these will become an order of magnitude stricter in 2017. The choice of injection strategy can play an important role in reducing the source of these emissions during combustion, which are chiefly caused by rich mixture combustion. This in turn occurs due to mixture inhomogeneity and combustion around liquid films and liquid droplets. This thesis outlines work undertaken to improve understanding of gasoline mixture preparation processes, simulation of droplet evaporation, flash boiling, spray evaporation and spray penetration, and experimental investigation of fuel sprays in an optical spray chamber and an optical engine. Assessments of the suitability of different sub-models for spray simulation were needed, in order to capture enough of the spray physics and fuel behaviour to aid correct prediction of spray evaporation, mixture homogeneity and fuel impingement by Computational Fluid Dynamics (CFD) packages. Phenomena have been explored on the individual droplet scale, including non-ideal behaviour of fuel mixtures, models for droplet heating/cooling during spray evaporation, the behaviour of superheated droplets under flash boiling conditions and multi-component fuel evaporation formulations. Detailed droplet evaporation routines have been created in MATLAB and single droplet studies performed under a range of conditions encountered in a DISI engine cylinder. From these results, recommendations have been made regarding the required complexity of droplet models for accurate predictions, at various fuel injection conditions. It was found necessary to model the non-ideal vapour-liquid equilibrium of ethanol-containing model gasoline fuels, for ethanol content of 10% by volume and above, and to include models for a non-uniform droplet temperature model across most fuels and in-cylinder conditions studied. In addition, the effect of finite liquid species mixing in the fuel droplet was deemed to be important to consider for non-ideal fuel mixtures. Sub-models for droplet evaporation, incorporating non-ideal fuel behaviour, have been created for an OpenFOAM Lagrangian Particle Tracking spray CFD solver. Results from these runs confirm that trends observed at a single droplet level are typically apparent at the spray scale. It was then possible to predict the effects that different evaporation modelling approaches had on spray penetration, which is important when assessing the extent of fuel spray impingement. Including a model for the non-uniform temperature distribution inside the droplet (finite thermal conductivity) was found not to influence the overall spray behaviour as much as expected, due to the competing effects of droplet break-up, droplet collisions and gas phase cooling. Numerical predictions have been compared with findings from spray imaging investigations in a purpose-built continuous flow, atmospheric pressure spray chamber, and with findings from optical engine experiments. In addition, adiabatic flash calculations have been performed to predict the degree of flash evaporation expected under flash boiling conditions, to help to interpret the results from flash boiling spray experiments. Various images from fuel spray experiments that represent different engine conditions have been taken and analysed for axial penetration, fuel impingement, structure and evaporation rate. These have helped to understand how a certain spray might lead to conditions where increased particulate emissions are likely. The fuels used during these tests were model gasoline fuels, containing 15% methanol by volume. This type of mixture represented fuel commercially available in some markets and was chosen to investigate the effects of a highly non-ideal and volatile fuel under both superheated and sub-cooled spray conditions. It was found that, as the degree of superheat was increased, the spray collapse tended to intensify, leading eventually to increased liquid penetration, a greater degree of spray impingement and a stratification of fuel towards the cylinder centre. Optical engine experiments have been performed using an early injection strategy for homogeneous operation, at 0.5 bar inlet plenum pressure, for various fuel temperatures and injection timings. Particulate number measurements were taken from the exhaust, and were found to be highest when the fuel was hottest and at typical early injection timings. Retarding or advancing the injection was found to reduce the particulate number count.

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Meyer, Jason. "Calibration reduction in internal combustion engine fueling control: modeling, estimation and stability robustness." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306682834.

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40

Lehtinen, Tuomas. "Internal Combustion of an Asteroid Recorded Using a Spacecraft (ICARUS) : Mission Definition Review." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76148.

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41

Conradie, P. A. (Petrus Alwyn). "The development of a dynamic engine-testing facility." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52509.

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Thesis (MScEng.)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: The last two decades have seen many changes within the automotive industry. Many advances have been made in the design, research and development of the internal combustion engine and technological progress made in the integrated-circuit and computer industry has resulted in the availability of reliable low-cost electronic components. These components have, over time, been incorporated into the very hearts of engines, thereby allowing for the accurate control of engine functions and processes to an extent that was previously impossible. Parallel to these developments is the growing concern for the environment and the realisation that resources are being consumed at ever-increasing rates. This has placed vehicle manufacturers under continual pressure to optimise their engines, not only for fuel efficiency, but also to reduce harmful emissions while continuing to deliver better performance and drivability characteristics. At the same time, engine testing equipment and facilities have had to keep abreast with these advances and this has required the development of more sophisticated testing facilities. One such facility is the dynamic engine test-bed. Among other features, this facility has the ability to subject test-bed mounted engines to loads similar to what would be experienced in a vehicle on the road. This approach allows for the optimisation of engine components and performance under more realistic conditions, yielding results far superior to those obtainable using more conventional steady-state testing and development procedures. This document discusses the development of such a dynamic engine test-bed at the Centre for Automotive Engineering at the University of Stellenbosch. The project was initiated by conducting a literature survey to establish the current state of technology in the field. The dynamic test-bed was developed around an existing direct-current electric motor and industrial speed controller configured in a regenerative manner. This setup enabled the unit to both absorb and deliver power, essential for the simulation of vehicle dynamics. Great care was taken to ensure that signals obtained from the test-bed were accurate and useful for further computer manipulation. Anti-aliasing filters were designed and manufactured to guarantee that signals could not be misinterpreted due to sampling effects. A computer-implemented vehicle model was developed to simulate, in real-time, vehicle response to torque developed by the engine on the test stand. The model included a manual transmission, clutch and a rigid drive-shaft. Driver input (accelerator, brake, clutch and gear selection) was by means of a set of pedals and hand-held gear selector switches. Various vehicle speed control strategies were investigated and recommendations made regarding their possible future implementation. System evaluation was accomplished by the simulated acceleration of a large truck. The simulations indicated that repeatable results could be obtained from the system. The system was also found to be adequately sensitive to reflect the effect of subtle changes made to engine parameters on vehicle acceleration. It was concluded that the dynamic engine test-bed did indeed offer the capability to conduct research and testing not previously available in South Africa. Finally, recommendations were made for the future improvement and expansion of the system's performance and capabilities.
AFRIKAANSE OPSOMMING: Die laaste twee dekades het baie veranderinge in die outomobiel industrie megebring. Groot vooruitgang is gemaak in die ontwerp, navorsing en ontwikkeling van die binnebrand enjin, terwyl tegnologiese vooruitgang in die geïntegreerde-stroombaan en rekenaar industrië betroubare elektroniese komponente teen lae koste beskikbaar gemaak het. Hierdie komponente is mettertyd in enjins geïnkorporeer en het die akkurate beheer van enjin funksies en prosesse moontlik gemaak. Saam met hierdie ontwikkeling, is daar toenemende kommer oor die omgewing en 'n bewuswording dat hulpbronne verbruik word teen 'n groeinde tempo. Hierdie feite plaas voertuig vervaardigers onder volgehoude druk om enjins te optimeer vir brandstof doeltreffendheid, maar ook om skadelike emissies te bekamp terwyl beter werksverrigting en bestuurbaarheid vereis word. Enjin toetstoerusting en fasiliteite moes terselfdetyd met hierdie vooruitgang byhou en het die ontwikkeling van meer gesofistikeerde toetsfasiliteite vereis. Een sodanige fasiliteit is die dinamiese enjin toetsbank. Een van die kenmerke van hierdie fasiliteit is dat dit toetsbank-gemonteerde enjins kan onderwerp aan 'n las soortgelyk as wat ondervind sou word in 'n voertuig op die pad. Hierdie benadering stel ingenieurs in staat om enjin komponente en werksverrigting te optimeer onder meer realistiese kondisies en lewer resultate van 'n baie hoër gehalte as wat verkry kan word deur gebruik te maak van meer konvensionele gestadigde-toestand toets- en ontwikkelings-prosedures. Hierdie dokument bespreek die ontwikkeling van so 'n dinamiese enjin toetsbank by die Sentrum vir Automobielingenieurswese aan die Universiteit van Stellenbosch. Die projek is geïnisieer deur 'n literatuurstudie te doen om die huidige stand van tegnologie in die gebied vas te stel. Die dinamiese enjintoetsbank is ontwikkel rondom 'n bestaande gelykstroom-motor en industriële spoed beheerder wat in 'n regeneratiewe konfigurasie opgestel is. Hierdie opstelling het die absorpsie en lewering van drywing moontlik gemaak, 'n vereiste vir die simulasie van voertuig dinamika. Baie tyd is gespandeer om te verseker dat seine afkomstig van die toetsbank akkuraat en bruikbaar was vir verdere rekenaar manipulasie. Anti-aliaseringsfilters is ontwerp en vervaardig om te verseker dat seine nie verkeerd geïnterpreteer kon word as gevolg van diskritiserings effekte nie. 'n Rekenaar ge-implementeerde voertuigmodel is ontwikkel om 'n voertuig se reaksie op draairnoment ontwikkel deur die enjin op die toetsbank intyds te simuleer. Die model het 'n handrat transmissie, koppelaar en starre dryf-as ingesluit. Bestuurder intree (vernellingspedaal, rem, koppelaar en rat seleksie) is bewerkstellig deur middel van 'n stel pedale en 'n hand geoperateurde rat skakelaar. Verskeie voertuig spoed-beheerders is ondersoek en aanbevelings is gemaak aangaande die toekomstige implementering daarvan. Die sisteem is geëvalueer deur die versnellingsimulasie van 'n groot vragmotor. Die simulasies het daarop gedui dat herhaalbare resultate van die sisteem verkry kon word. Daar is ook bevind dat die sisteem sensitief genoeg was om subtiele veranderinge aan enjinparameters in die resultate te weerspieël. Die gevolgtrekking is gemaak dat die dinamiese enjin toetsbank inderdaad die vermoëns gebied het om ontwikkeling en toetswerk te doen wat nie voorheen in Suid-Afrika moontlik was nie. Voorstelle is laastens gemaak aangaande die toekomstige verbetering en uitbreiding van die sisteem se vermoëns.

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42

Baelden, Camille. "A multi-scale model for piston ring dynamics, lubrication and oil transport in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92151.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 215-218).
Fuel consumption reduction of more than 20% can be achieved through engine friction reduction. Piston and piston rings contribute approximately half of the total engine friction and are therefore central to friction reduction efforts. The most common method to reduce mechanical losses from piston rings has been to lower ring tension, the normal force providing sealing between the piston ring and the cylinder liner. However tension reduction can result in additional lubricant consumption. The objective of this thesis is to understand and model the physical mechanisms resulting in flow of oil to the combustion chamber in order to achieve optimal designs of piston rings. The optimal design is a compromise between friction reduction and adequate gas and lubricant sealing performance. To do so a multi-scale curved beam finite element model of piston ring is developed. It is built to couple ring deformation, dynamics and contact with the piston and the cylinder. Oil flow at the interfaces between the ring and the cylinder liner and between the ring and the piston groove can thus be simulated. The piston ring model is used to study the sealing performance of the Oil Control Ring (OCR), whose function is to limit the amount of oil supplied to the ring pack. The contributions of the three main mechanisms previously identified, to oil flow past the OCR are quantified: - Deformation of the cylinder under operating conditions can lead to a loss of contact between the ring and the liner. - Tilting of the piston around its pin can force the OCR to twist and scrape oil from the liner. - Oil accumulating below the OCR can flow to the groove and leak on the top of the OCR The OCR is found to be flexible enough to limit the impact of cylinder deformation on oil consumption. Both ring scraping and flow through the OCR groove can contribute to oil consumption in the range of engine running conditions simulated. Reduction of scraping is possible by increasing the ability of both OCR lands to maintain contact with the liner regardless of piston groove tilt. The flow of oil through the OCR groove can be reduced by designing appropriate draining of oil in the groove and an adequate oil reservoir below the OCR. The piston ring oil transport model developed in this thesis will be a valuable tool to optimize ring pack designs to achieve further ring pack friction reduction without increasing oil consumption.
by Camille Baelden.
Ph. D.

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43

Chen, Haijie. "Modeling the lubrication of the piston ring pack in internal combustion engines using the deterministic method." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67578.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 131-133).
Piston ring packs are used in internal combustion engines to seal both the high pressure gas in the combustion chamber and the lubricant oil in the crank case. The interaction between the piston ring pack and the cylinder bore contributes substantially to the total friction power loss for IC engines. The aim of this thesis work is to advance the understanding of the ring liner lubrication through numerical modeling. A twin-land oil control ring lubrication model and a top two-ring lubrication model are developed based on a deterministic approach. The models take into consideration the effect of both the liner finish micro geometry and the ring face macro profile. The liner finish effect is evaluated on a 3D deterministically measured liner finish patch, with fully-flooded oil supply condition to the oil control rings and starved oil supply condition to the top two rings. Correlations based on deterministic calculations and proper scaling are developed to connect the average hydrodynamic pressure and friction to the critical geometrical parameters and operating parameters so that cycle evaluation of the ring lubrication can be performed in an efficient manner. The models can be used for ring pack friction prediction, and ring pack/liner design optimization based on the trade-off of friction power loss and oil consumption. To provide further insights to the effect of liner finish, a wear model is then developed to simulate the liner surface geometry evolution during the break-in/wear process. The model is based on the idea of simulated repetitive grinding on the plateau part of the liner finish using a random grinder. The model successfully captures the statistic topological features of the worn liner roughness. Combining the piston ring pack model and the liner finish wear model, one can potentially predict the long term ring pack friction loss. Finally the thesis covers the experimental validation of the twin-land oil control ring model using floating liner engine friction measurements. The modeled ring friction is compared with the experimental measurement under different ring designs and liner finishes. The result shows that the model in general successfully predicts the friction force of the twin-land oil control ring/liner pair.
by Haijie Chen.
Ph.D.

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44

Frank, Richard Milton. "A computer model for the heat losses in the exhaust manifold of an internal combustion engine." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/100066.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 87-88.
by Richard Milton Frank.
M.S.

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45

Xu, Dian. "Modeling the structural behavior of the piston rings under different boundary conditions in internal combustion engines." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61926.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 71-72).
In the process of designing internal combustion engine, piston ring plays an important role in fulfilling the requirements of camber gas sealing, friction reduction and lubrication oil consumption. The goal of this thesis is to have a better understanding of the ring behaviors under different working conditions in a structural level. This thesis is an extension of existing ring design tool. A model is built up to simulate the processes of changing ring states from one to another such as free or fit the ring. It revealed the sensitive characters of the piston ring tip; it expanded the field of application of the existing piston ring design tool; it also investigated the ring bore interaction in more conditions. This work removed the symmetric assumption in the existing tool. A new method that calculates ring free shape and ring bore contact force from ring ovality data is introduced for the first time. The analysis of ring bore interaction is widened. The model was applied to an industry ring design case. In this case it shows the free and fit procedure in this model is physically and mathematically reversible. It shows these procedures are direction independent. The contact force distribution changes when the ring is moving within the distorted bore. It also changes when the wetting or roughness situation is different. This model can calculate the ring free shape from asymmetric measured ovality data. It can also retrieve the desired contact force from it. The piston ring design tool is updated and implemented with these highly appreciable new features. This complete package has high efficiency and a wider practical field.
by Dian Xu.
S.M.

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46

Manz, Devon L. "High-speed video observation and on-line measurements of oil aeration in an internal combustion engine." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32358.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 91-92).
Along the oil's journey through the oil lube system, the oil lubricates, cools, removes impurities, supports load, and minimizes friction. At the end of the oil's journey it returns to the sump where it remains nearly motionless until it re-enters the oil pick-up and restarts its journey. This study is focused on the creation and destruction mechanisms of air in the oil. To study this, a motored Ford 3.OL V6 DOHC engine test apparatus was designed, fabricated and instrumented to operate at 8000rpm and at engine oil temperatures below 110ÌC. Visual observations and quantitative measurements of oil aeration were performed in the oil sump. The oil aeration process was visualized in the oil sump using high-speed video equipment, at engine speeds below 4000rpm. Oil droplets were observed to depart the crankshaft at approximately the tangential velocity, pass through drainage gaps in the windage tray, and strike the free surface of the oil. The rhythmic pulsation of oil droplets on the free surface caused the surface to slosh at the frequency of the crankshaft's rotation. Foam was observed to form above a threshold speed and a threshold temperature. The windage tray was observed to reduce the droplet number density. When the windage tray was removed, the increased droplet number density inhibited foam formation. An x-ray absorption measurement technique was used to measure oil aeration at multiple locations in the oil sump. An experimental methodology was developed and preliminary experiments were performed with and without the windage tray at oil volumes below 5L, engine speeds below 6000rpm, and oil temperatures below 110ÌC.
(cont.) Aeration measurements reveal a general increase in aeration as a function of engine speed at all locations in the oil sump. In the oil sump, more air is present at the oil surface than at the oil pick-up because air continuously leaves the oil at the air-oil interface. When the engine shuts down, all of the oil in the lube path drains back into the oil sump, and in a short period of time all of the air bubbles rise to the surface and escape the oil. It is the balance between air entering the oil (creation mechanisms) and air leaving the oil (destruction mechanisms) that is the focus of this study.
by Devon L. Manz.
S.M.

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47

Saleh, Naseer Ahmed. "Investigation of reciprocating internal combustion engine structure response and vibration transmission using a hydraulic simulation technique." Thesis, University of Southampton, 1987. https://eprints.soton.ac.uk/52287/.

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The success of theoretical engine noise prediction, using such techniques as finite element modelling, is highly dependent upon the understanding of the various mechanisms of noise generation in the running engine. The forcing mechanism of an operating engine is complicated as it involves a large number of forces taking place simultaneously or in rapid succession at various positions in the structure. A number of test methods have been developed to simulate individually each one of these loading mechanisms on non-running engines. These test methods are reviewed in this thesis with an objective judgement on their representation of the actual forcing on the running engine. A new hydraulic test method has been successfully developed to simulate various forms of loading mechanisms on the non-running engine like the gas force on top of the piston, main bearings axial and vertical loading, and piston slap force. This test method is shown to be more comprehensive, realistic, practical and representative than previous simulation techniques, especially with respect to the level of forcing which corresponds well with that of the running engine. The structural sensitivity of the engine has been evaluated for different representative loading, the most sensitive input being that of the axial force at the main bearings. The damping characteristics of a large six cylinder diesel engine block has been calculated and the crank shaft is shown to affect it as well as affecting the wave propagation through the structure. The simulation technique has also allowed the detailed study of the various forms of wave propagation in a diesel engine load carrying structrue and this has shown the importance of both bending and longitudinal travelling waves in noise radiation. It is shown that bending waves provide the maximum amplitudes of vibration, whereas longitudinal wave propagation allows for the fast transfer of energy through the structure which can then convert into bending waves with high noise radiation potential. Analysis of the results has shown that some doubt must be placed on the normal mode method for predicting the response in the lower frequency range, and an alternative model based on highly damped travelling bending waves is visualized to be suitable to model the crank case wall but not the stiff upper.

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48

Rangarajan, Bharadwaj. "Robust concurrent design of automobile engine lubricated components." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/18897.

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49

Pál, Tamás. "Perspectives for mini-scale ORCpower plants coupled with internal combustion engines in the European Union." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-216148.

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50

Follen, Kenneth. "A System Dynamics Modeling Methodology for Compressible Fluid Systems with Applications to Internal Combustion Engines." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281971505.

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Dissertations / Theses on the topic 'Internal Combustion Engineering'

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