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1
Price, Philip Daniel. "Direct injection gasoline engine particulate emissions." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:35c0d6bf-bde3-4ef0-a87e-4af89a94b16f.
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Direct fuel injection technology is increasingly being applied to the spark ignition internal combustion engine as one of the many actions required to reduce the CO2 emissions from road transport. Whilst the potential for CO2 reductions is compelling, the technology is not without disadvantages. Early examples typically emitted over an order of magnitude more Particulate Matter (PM) than vehicles with conventional spark ignition engines. Consequently, future revisions to European and North American exhaust emissions legislation are likely to regulate the particulate emissions from vehicles with direct injection gasoline engines. This thesis undertakes to investigate a) instrumentation capable of simultaneously resolving the number concentration and size distribution of particles in the 5-1000 nm size range and b) the factors affecting the PM emissions from spark ignition engines with direct fuel injection. The first objective is achieved by evaluation and comparison of a differential mobility spectrometer; photo-acoustic soot sensor; condensation particle counter and electrical low pressure impactor. To address the second question, a differential mobility spectrometer is applied to quantify the PM emissions from a number of direct injection gasoline engines, together with investigation of their dependence on various calibratable parameters, operating temperature and fuel composition. The differential mobility spectrometer showed good agreement with the other more established instruments tested. Moreover, it exhibited a faster time response and finer resolution in particle size. The number weighted size distribution of the PM emitted was typically lognormal with either one or two modes located between 20 and 100 nm. Chemical analysis of PM samples showed the presence of elemental carbon, volatile organic material and sulphates. Transient PM measurements enabled short time-scale events such as mode switching between homogeneous and stratified mixture preparation to be identified. PM number concentrations in stratified mode exceeded those in homogeneous mode by a factor of 10-100. Dynamometer based experiments showed that PM emissions increase for rich air fuel ratios, retarded fuel injection and advanced ignition events. They also demonstrated a strong dependence on fuel composition: the highest PM emissions were measured with an aromatic fuel, whereas blending alcohols such as methanol or ethanol tended to suppress PM emissions, particularly in the accumulation mode size range. These measurements are amongst the first of their kind and demonstrate the applicability of the differential mobility spectrometer to the measurement of ultra-fine particulate emissions from engines with direct fuel injection systems. Numerous explanations are put forward to describe the data obtained, together with suggestions for future work on PM control and abatement.
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Maugham, Robin. "Dilution torque control of a gasoline engine." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268735.
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Niekamp, Troy S. (Troy Steven). "Translation of dilution tolerance for gasoline SI engine." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81616.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 69-70).
There are a variety of fuel improvement strategies being developed for spark ignition engines which use dilution. Many of these technologies use a combination of different diluents. It is impractical in optimizing these technologies to test every possible combination of diluents. The purpose of this study was to determine a relationship between the various diluents and combustion related output parameters. One of these key outputs was determining the dilution tolerance for an engine. In order to achieve this goal, the fundamental of combustion were studied. The results from this study will be useful in developing more aggressive engine control strategies. Dilution has been studied extensively in previous research. Its effects are well known. Primarily, it reduces peak combustion temperatures. This can be used as an effective means to reduce losses and hazardous emissions. Too much dilution, however, and the combustion stability is compromised. To facilitate this project, an engine was fully instrumented. Experiments were performed for a variety of operating conditions and diluents. Results were then used to correlate the diluent properties and quantities to combustion outputs. Adiabatic flame temperature was first attempted as the key metric for correlation. This metric proved to be unsuitable for developing correlations. Later, a new metric was computed by taking a linear combination of diluents. This was found to offer superior results. Using this metric along with other basic engine measurements, correlations were developed between the diluents and engine output parameters. These output parameters include dilution tolerance, exhaust temperature, NOx emissions, and combustion bum durations.
by Troy S. Niekamp.
S.M.
4
Osborne, Richard J. "Controlled auto-ignition processes in the gasoline engine." Thesis, University of Brighton, 2010. https://research.brighton.ac.uk/en/studentTheses/1bf3c062-1d30-4d94-8c68-3c00da31e22d.
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Controlled auto-ignition (CAI) combustion – also described as homogeneous charge compression ignition (HCCI) combustion – was investigated. The primary experiments concerned a direct-injection single-cylinder gasoline engine equipped with a poppet valve combustion system. This engine was operated with both the two-stroke working cycle and the four-stroke cycle. The engine experiments were used to establish combustion characteristics and the envelope of operation for CAI combustion, and to investigate the influence of a number of engine parameters including engine speed and load, air-fuel ratio, intake-air heating and exhaust-port throttling. Results from one-dimensional fluid-dynamic calculations were used to support the main data set and to develop hypotheses concerning CAI combustion in practical gasoline engines. Images from parallel investigations using an equivalent optical-access engine, and three-dimensional fluid-dynamic calculations, were used to supplement the results generated by the author and to further develop and test understanding of gasoline CAI processes. Finally practical implementation of CAI combustion in passenger vehicles was considered, including possible routes to series production of CAI engines.
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Beavis, Nicholas J. "Numerical studies of gasoline direct injection engine processes." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25230.
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The GDI engine has a number of practical advantages over the more traditional port-fuel injection strategy, however a number of challenges remain the subject of continued research in an attempt to fully exploit the advantages of the GDI engine. These include complex in-cylinder flow fields and fuel-air mixing strategies, and significant temporal variation, both through an engine cycle and on a cycle-by-cycle basis. Despite advances in experimental techniques, the relative difficulty and cost of taking detailed measurements remains high, thus computational techniques are an integral part of research activities. The research work presented in this thesis has focused on the use of detailed 3D-CFD techniques for investigating physical phenomena of the in-cylinder flow field and fuel injection process in a single cylinder GDI engine with early injection event. A detailed validation of the numerical predictions of the in-cylinder flow field using both the RANS RNG k-ε turbulence model and the Smagorinsky LES SGS turbulence model was completed with both models showing good agreement against available experimental results. A detailed validation of the numerical predictions of the fuel injection process using a Lagrangian DDM and both RANS RNG k-ε turbulence model and Smagorinsky LES SGS turbulence model was completed with both models showing excellent agreement against experimental data. The model was then used to investigate the in-cylinder flow field and fuel injection process including research into: the three dimensional nature of the flow field; intake valve jet flapping, characterisation, causality and CCV, and whether it could account for CCV of the mixture field at spark timing; the anisotropic characteristics of the flow field using both the fluctuating velocity and turbulence intensity, including the increase in anisotropy due to the fuel injection event; the use of POD for quantitatively analysing the in-cylinder flow field; investigations into the intake valve, cylinder liner and piston crown spray plume impingement processes, including the use of a multi-component fuel surrogate and CCV of the formed liquid film; characterisation and CCV of the mixture field though the intake and compression strokes up to spark timing. Finally, the predicted turbulence characteristics were used to evaluate the resultant premixed turbulent combustion event using combustion regime diagrams.
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Alexander, Paul. "Mixture preparation processes in a direct injection gasoline engine." Thesis, University of Brighton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411916.
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Bucknell, Roger John. "Control system for a gasoline engine including dual spark." Thesis, University of Hertfordshire, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314566.
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Alrefae, Waleed H. "Combustion studies in an optically accessed gasoline direct injection engine." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439607.
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Davy, Martin Howard. "Two-phase fuel visualisation in a direct-injection gasoline engine." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341747.
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Lewis, Raymond (Raymond A. ). "High compression ratio turbo gasoline engine operation using alcohol enhancement." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85488.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Page 62 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (page 61).
Gasoline - ethanol blends were explored as a strategy to mitigate engine knock, a phenomena in spark ignition engine combustion when a portion of the end gas is compressed to the point of spontaneous auto-ignition. This auto-ignition is dangerous to the operation of an internal combustion engine, as it can severely damage engine components. As engine designers are trying to improve the efficiency of the internal combustion engine, engine knock is a key limiting factor in engine design. Two methods have been used to limit engine knock that will be considered here; retarding the spark timing and addition of additives to reduce the tendency of the fuel mixture to knock. Both have drawbacks. Retarding spark reduces the engine efficiency and additives typically lower the heating value of the fuel, requiring more fuel for a given operating point. To study this problem a turbocharged engine was tested with a variety of combinations of gasoline and ethanol, an additive with very good anti-knock abilities. Pressure was recorded and GT Power simulations were used to determine the temperature within the cylinder. An effective octane number was calculated to measure the ability of the fuel to resist knock. Effective octane numbers varied from 91 for UTG91 to 111 for E25, respectively. Engine simulations were used to extrapolate to points that couldn't be tested in the experimental setup and generate performance maps which could be used to predict how the engine would act inside of a vehicle. It was found that increasing the compression ratio from 9.2 to 13.5 leads to a 7% relative increase in part load efficiency. When applied in a vehicle this leads to a 2-6% increase in miles per gallon of gasoline consumption depending on the drive cycle used. Miles per gallon of ethanol used were significantly higher than gasoline; 141 miles per gallon of ethanol was the lowest mileage over all cycles studied.
by Raymond Lewis.
S.M.
11
Arning, Johannes. "Experimental studies of combustion control in a gasoline HCCI engine." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609247.
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Raimbault, Vincent. "Benefit of air intake optimization for new turbocharged gasoline engine." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0024.
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Ces dernières années les ventes de moteurs à allumage commandé sont croissantes. Pourtant les exigences en termes d’émissions de CO2 et d’émissions polluantes sont devenues plus contraignantes, taxant lourdement les dépassements. De plus le cycle d’homologation a évolué vers un élargissement de la fenêtre d’utilisation du moteur ou les émissions sont réglementées. La réduction de cylindrée « downsizing » opérée ces dernières années a permis de réduire les consommations notamment grâce à la réduction des pertes par pompage. Les performances ont pu être maintenues par l’adoption de système de suralimentation et notamment du turbocompresseur. Celui-ci présente toutefois une lacune à bas régime où il ne peut fournir une réponse instantanée et où la pression desuralimentation est limitée. De même à plus haut régime le fort taux de compression utilisé pour augmenter le rendement du moteur rend difficile le contrôle du cliquetis. Cette thèse s’est focalisée sur l’utilisation des ondes de pression pour améliorer la réponse du moteur à bas régime. Tout d’abord avec des outils de simulation puis en validation sur banc moteur. Une seconde partie a permis de développer une architecture de ligne d’admission d’air permettant de réduire la température d’admission afin d’augmenter la résistance au cliquetis et d’augmenter l’avance à l’allumage. La température d’échappement est ainsi réduite. Celle-ci est un élément dimensionnant de la stratégie moteur qui a maintenu, dans ces travaux, un mélange stoechiométrique afin de limiter les émissions polluantesThe last years have witnessed a strong increase of the sold spark ignition engines. Furthermore the new regulations are formally constraining pollutant emissions and CO2 with high fines. In the same time the new homologation driving cycle extends the engine operating conditions where the emissions need to be controlled. The downsizing has been a strong lever over the last years to improve the fuel consumption with reduction of the throttling and thus the pumping losses. With the downsizing, the turbocharger has been widely adopted to maintain the output performance. The implementation of turbocharger challenges the time to torque and the low end torque at low engine speed. In the same time the increase of boost pressure associated to high compression ratio confront the knock controls at maximum power operating conditions. This thesis focuses on acoustic boosting with volumetric efficiency enhancement to improve the low end torque and the time to torque. Firstly a simulation model allows taking into account the combustion behavior as well as the turbocharger characteristics. The intake geometry has been optimized to enhance the engine response time and low end torque. The second part deals with the pressure wave action used to reduce the intake temperature and thus improve the knock resistance being beneficial for exhaust gas temperature reduction. The interaction between the waves created the different cylinder is demonstrated. The test has confirmed the power increase while maintaining lambda 1 and thus keeping the three way catalyst efficient
13
Mägi, M. "Effect of gasoline fuel additives on combustion and engine performance." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1462024/.
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Ever increasing emissions regulations and demand for fuel economy have brought about great advances in fuel and engine technologies. Improving engine efficiency through the use of fuel additives has been practiced for nearly a century but advances to direct injection gasoline engines have presented new obstacles that need to be overcome. With direct injection systems often suffering from reduced timescales allowed for combustion processes, atomisation and vaporisation characteristics have become of paramount significance. Present study aimed at adding to the field of knowledge by experimentally investigating commercial fuel additives of different functional iti es against their effects on fuel atomisation and combustion characteristics. Fuel atomisation was evaluated through the use of a laser diffraction system and measurement of fuel viscosity and surface tension. Additives from six functional groups were investigated. Additionally, effects of anti-knock and ignition promoting additives on gasoline combustion behaviour were studied in a constant volume combustion vessel and a single cylinder research engine. Flame speed, heat release rate and emissions output were compared for three commercially available combustion improvers. Investigation into the effect of fuel additives on the physical properties and therefore on fuel atomisation and sprays revealed that in commercially employed quantities, no significant change in recorded Sauter Mean Diameter could be observed. Combustion investigations in a combustion vessel demonstrated that the low temperature reactions initiated by ignition promoting additive reduced CO emissions up to 37.7 % which could be attributed to possible reduced flame quenching near combustion chamber walls. However, in high quantities this reduction in CO levels was not experienced. Addition of anti-knock additives resulted in increased NOx emissions, which was thought to result from increased combustion durations. Present work has clarified fuel additive function and interactions with combustion processes and has demonstrated that gasoline fuel additives do not interfere with combustion processes outside their intended functionality.
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Smith, Oliver Mark Edward. "In-cylinder fuel and lubricant effects on gasoline engine friction." Thesis, University of Leeds, 2007. http://etheses.whiterose.ac.uk/4716/.
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The purpose of the research reported in this thesis was to investigate the viability and quantify the potential gains of improving fuel economy of the gasoline engine through strategic application of additives. An increased awareness of the link between greenhouse gas emissions and global warming means that there is a desire to reduce carbon dioxide emissions from transportation. There is therefore a growing emphasis on improving the fuel economy performance of vehicles. The addition of friction modifier additives to the fuel is one way to achieve this. Using bespoke in-cylinder sampling techniques, an understanding of the operation of the piston assembly, a system responsible for much of the power loss in the internal combustion engine, is developed. Validation is given to the hypothesis that fuel economy gains can be achieved through the application of friction modifier administered to the engine via the gasoline. Results show gasoline administered friction modifier additive can accumulate in the piston assembly lubricant at levels 77 times greater than the initial fuel treatment level. The performance of a large number of friction modifier additives were uniquely screened in a novel bench-top test which simulated the arduous in-cylinder conditions found in a firing gasoline engine. The test generated vast amounts of information which led to high performance formulations capable of reducing the friction coefficient in both the boundary and mixed lubrication regimes by around 50% when compared with the result for the base oil alone. Surface analysis techniques were also employed 0!l engineering surfaces coated with friction modifier additives and add to the knowledge of their mechanism of action. Finally a series of engine tests were conducted which prove the effectiveness of friction modifier administered to the engine via the gasoline. A fuel economy improvement of approximately 2% was seen where friction modifier gasoline was employed. Application of successful technology such as this is shown to correspond to the projected saving of around 502 million litres of gasoline and 388,000 tonnes of carbon (C02) per year in the UK alone.
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Lourenco, Cardosa Tiago José Peres. "Port fuel injection strategies for a lean burn gasoline engine." Thesis, University of Brighton, 2011. https://research.brighton.ac.uk/en/studentTheses/70452fa8-4e63-42dd-8403-05dc6d8d4d60.
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A spark ignition (SI) engine operating with a lean burn has the potential for higher thermal efficiency, and lower nitrogen oxide emissions than that of stoichiometric operation. However, a lean or highly diluted mixture leads to poor combustion stability impacting detrimentally upon engine performance. An experimental investigation was carried out, on a 4-valve single cylinder gasoline engine with a split intake tract and two identical production port-fuel injectors installed, allowing independent fuel delivery to each intake valve. The main objective of the study was to extend the limit of lean combustion through the introduction of charge stratification. Novel port fuel injection strategies such as, dual split injection, multiple injections and phased injection, were developed to achieve this goal. In parallel, a model of the engine was developed in the Ricardo WAVE software. The model was used to calculate parameters such as in-cylinder residual gas, for different test points. Combustion stability was improved for the engine conditions tested. At 1000 rpm and 1.0 bar gross indicated mean effective pressure (GIMEP), the lean combustion limit was extended from a 14:1 air-to-fuel ratio (AFR) to 17.5:1. At 1500 rpm and 1.5 bar GIMEP the lean combustion limit was extended from 17.5:1 to approximately 21:1 AFR. Finally for 1800 rpm and 1.8 bar GIMEP, lean combustion was improved from 21: 1 AFR to 22: 1 An experimental spark plug, with an infrared detector, was used to measure the variation in fuel distribution at the spark plug gap. It showed that the different fuel injection strategies generated different levels of fuel concentration. It was identified that injections in a single port created fuel stratification in the spark plug area but were more prone to cycle to cycle variations in fuel concentration. These variations did not correlate with combustion stability or flame speed propagation at the speeds and loads tested. The most important parameter to influence the flame propagation speed was found to be the variation in local lambda with crank angle just after the ignition timing. It was shown that the fastest flame propagation speeds did not necessarily result in the lowest CoV in GIMEP. Finally the fuel injection strategies were investigated for highly dilute conditions, achieved by means of internal residual gas trapping, with the aim of promoting (spark-assisted) compression ignition combustion conditions.
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Asadamongkon, Pichai. "Characteristics of the flow through dual-intake valve gasoline engines." Thesis, King's College London (University of London), 2001. https://kclpure.kcl.ac.uk/portal/en/theses/characteristic-of-the-flow-through-dualintake-valve-gasoline-engines(979cef81-fa33-42a1-a0f4-8bbd79f21bc9).html.
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Mirmohammadsadeghi, Mahmoudreza. "Investigation of diesel-ethanol and diesel-gasoline dual fuel combustion in a single cylinder optical diesel engine." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17436.
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Ever growing population and increased energy consumption across all industries has resulted in higher atmospheric concentration of the greenhouse gases (GHG) and therefore an increase in the planet's average temperature, which has led to increasingly demanding and more strict legislations on pollutant sources, and more specifically, the automotive industry. As a consequence of all this, the demand for research into alternative energy sources has greatly increased. In this study combustion characteristics, engine performance, and exhaust emission of diesel-ethanol and diesel-gasoline are investigated in an optical direct injection diesel engine. In particular, effects of different substitution ratios and diesel injection strategies are studied when the total fuel energy is kept constant. The three main substitution ratios used in this study include 45% (45% of fuel energy from port-injected ethanol/gasoline and 55% from direct injection diesel), 60%, and 75%. The engine used for this investigation is a Ricardo Hydra single cylinder optical engine running at 1200 rpm. In-cylinder pressure measurement is used for calculating all engine parameters, heat release rate, and efficiency. In addition to the thermodynamic analysis of the combustion parameters, high speed camera was used alongside with a copper vapor laser or the high speed image intensifier in the high speed video imaging for the optical analysis of the effect of the above-mentioned parameters on autoignition and combustion processes, while Horiba particulate analyser and AVL smoke meter were utilized in monitoring and recording emissions for every tested condition. Depending on the testing conditions, such as injection strategy and intake conditions, both dual-fuel operations were able to deliver high efficiency and improved emissions compared to that of a pure diesel engine operation, with the diesel-gasoline operation offering more consistency in improved thermal efficiency, and the diesel-ethanol operation delivering lower emission output. The optical analysis of the combustion represents the main difference in the flame propagation, distribution and quality for each substitute fuel and its substitution percentage, as well as the condition under examination.
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Akma, Tengku N. "Miller cycle combustion strategy for downsized gasoline engines." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/32421.
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In response to the global concerns towards oil scarcity and climate change, the automotive industry is currently focusing on improving fuel economy and reducing exhaust emissions. Modern downsized gasoline engines that come with a package that includes a boosting system, variable valve train and direct fuel injection system is effective for fuel economy improvement and emission reduction. However, the knocking issue becomes severe at high load operations as a result of the high intake boosting pressure. In regard to the part load conditions, the gas exchange process requires extra work to draw in air into the cylinder due to a lower amount of pressure in the intake manifold caused by the restriction of the throttle plate. The Miller cycle is regarded as a potential strategy of knock control for downsized gasoline engines. Extensive works have sought to examine the performance improvement via the Miller cycle, yet only limited research has been conducted on the manner in which it can influence knock suppression. The focus of this thesis is to investigate early and late intake valve closing timings in terms of how they affect the compression process, the ability to suppress engine knock and meet the power output required at high loads for spark-ignited gasoline engines. Apart from that, this research also demonstrates the Miller cycle potential by utilising fully variable valve timing in controlling the load at the part load condition without using a throttle. The early intake valve closing with different valve lifts was tested in order to investigate the impact during the gas exchange process, particularly the pumping losses and the potential to improve fuel economy. This study includes both experimental and simulation studies. A Lotus single-cylinder research engine referred to as SCORE was mainly used for the experimental component of the study. The simulation work was conducted using a one-dimensional spark ignition engine model built in the Ricardo WAVE software for naturally-aspirated and downsized engines. The engine model values are validated against the experimental values from the Lotus SCORE and Lotus SABRE engines. The combustion model with a reduced kinetics mechanism was validated using a Rover K-series engine. A broad matrix of the engine operations has been investigated combining a variety of engine speeds and engine loads. The Miller cycle effects on knock suppression in a downsized engine environment have been investigated in three parts, namely the Miller cycle at different speed-load, knock suppression with extreme Miller cycle, and knock analysis with combustion kinetics. Through the works, the Miller cycle has demonstrated its capability to suppress engine knocking in a more efficient manner as opposed to the standard engine operation. This is contributed by the fact that early and late intake valve closings could affect the end gas condition at the end of the compression stroke, thus making it possible to suppress the engine knocking. The experimental study for controlling load without using throttle under the naturally-aspirated condition found that the Miller cycle with an early intake calve closing strategy able to improve fuel consumption by reducing pumping losses. The downsized engine condition, which has been evaluated via modelling work, also showed an improved performance trend using the unthrottled Miller cycle strategy. The open cycle and close cycle efficiencies have improved through the Miller cycle implementation. The contribution of this work is made in order to establish the comparison of the Miller cycle strategy in suppressing knocking between the early intake valve closing and late intake valve closing under a boosted environment. For the part load condition of the downsized engine, the research contributes to the existing body of knowledge by comparing the throttle-less Miller cycle and the standard throttled operation as a load control strategy.
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Tuvesson, Stefan. "Tuning and Validation of an MVEM for a Turbocharged Gasoline Engine." Thesis, Linköping University, Linköping University, Vehicular Systems, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16610.
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Rubino, Lauretta. "After-treatment of particulate emissions from simulated and gasoline engine exhausts." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406858.
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Ma, Hongrui. "Optical diagnostics and combustion analysis in a gasoline direct injection engine." Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:46364c15-08d3-4984-af3b-819ef0bdc847.
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Gasoline Direct Injection (GDI) engines work with stratified charge at part load and burn with lean mixtures in order to save fuel, whilst at full load, the fuel and air mix homogeneously for maximum power output. The higher compression ratio and the absence of throttling are two of the most significant benefits of GDI engines. The key issues facing GDI combustion include in-cylinder mixture preparation and post-combustion soot formation. This work was intended to investigate these aspects and was undertaken on a dedicated Jaguar single-cylinder optical GDI engine with a spray-guided combustion system. The spray-guided concept does not rely as much on charge motion or piston design, and can avoid wall-wetting effects so as to reduce engine emissions. Relevant engine control hardware and data acquisition equipment were commissioned. Data/image processing software was also developed to suit the measurements. A data-processing case study with data from a small two-stroke glow ignition engine has been conducted to develop a method to combine the burn rate and heat release analyses in the study of engines with premixed charge but compression ignition. Difficulties such as unknown ignition timing and polytropic index have been addressed. Results for all operating conditions have shown good correlations between the two methods. The technique of quantitative planar laser-induced fluorescence is useful for measuring 2-D fuel distribution in GDI engines. The relevant physics and literature were reviewed in depth. A multi-component fuel was designed to give reasonable co-evaporation characteristics with tracers matching different fuel fractions. The absorption and fluorescence features of each fuel component and tracer were characterised. Optimisation of hardware and signal-to-noise ratio was performed. A recirculating loop was set up for the calibration of the technique. The technique of colour-ratio pyrometry (CRP) for estimating the temperature and loading of soot was applied on the GDI engine. Critical features of the candidate CCD colour camera including its spectral response and noise behaviours were fully studied. Validation tests with reference sources together with an error analysis suggested an accuracy of ±50K within the combustion temperature range. Engine combustion images were then taken under various operating conditions. Temperature estimates were shown to be insensitive to the concentration of soot. Simulation with a thermodynamic modelling package, ISIS, was introduced for comparison with the experimental data. With careful tuning, ISIS gave outputs comparable to the CRP and proved to be a cost-effective tool to study GDI engines. High-speed combustion imaging was carried out using a CMOS camera, allowing the study of flame properties as well as crank-angle resolved CRP. By using a lens in the piston crown to give full bore optical access and appropriate image processing, the flame front could be detected reliably throughout the main combustion process.
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Bennett, Colin. "Reconstruction of gasoline engine in-cylinder pressures using recurrent neural networks." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/48644/.
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Knowledge of the pressure inside the combustion chamber of a gasoline engine would provide very useful information regarding the quality and consistency of combustion and allow significant improvements in its control, leading to improved efficiency and refinement. While measurement using incylinder pressure transducers is common in laboratory tests, their use in production engines is very limited due to cost and durability constraints. This thesis seeks to exploit the time series prediction capabilities of recurrent neural networks in order to build an inverse model accepting crankshaft kinematics or cylinder block vibrations as inputs for the reconstruction of in-cylinder pressures. Success in this endeavour would provide information to drive a real time combustion control strategy using only sensors already commonly installed on production engines. A reference data set was acquired from a prototype Ford in-line 3 cylinder direct injected, spark ignited gasoline engine of 1.125 litre swept volume. Data acquired concentrated on low speed (1000-2000 rev/min), low load (10-30 Nm brake torque) test conditions. The experimental work undertaken is described in detail, along with the signal processing requirements to treat the data prior to presentation to a neural network. The primary problem then addressed is the reliable, efficient training of a recurrent neural network to result in an inverse model capable of predicting cylinder pressures from data not seen during the training phase, this unseen data includes examples from speed and load ranges other than those in the training case. The specific recurrent network architecture investigated is the non-linear autoregressive with exogenous inputs (NARX) structure. Teacher forced training is investigated using the reference engine data set before a state of the art recurrent training method (Robust Adaptive Gradient Descent – RAGD) is implemented and the influence of the various parameters surrounding input vectors, network structure and training algorithm are investigated. Optimum parameters for data, structure and training algorithm are identified.
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Suyabodha, Apiwat. "Simulation of cyclic variability in gasoline engine under cold start conditions." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555749.
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Emissions from gasoline engines remain an important issue worldwide as they are both harmful to health and contribute to green house effects especially under cold start conditions. A major challenge of the automotive industry is to reduce harmful emissions as much as possible whilst continuing to reduce CO2 emissions. Three-way-catalytic converters have been used very successfully to convert the harmful gases before release to the environment but these devices have to reach their light-off temperature in order to activate the chemical reactions. Therefore, the conversion time is delayed and during the pre light-off period, high levels of emissions are released. An investigation into methods capable of increasing catalyst temperature under cold start conditions has been carried out. The most beneficial technique used in this research was the secondary air method. The method introduced extra air into the exhaust manifold which allowed the engine to run rich and then the residual unburned fuel to be oxidised in the exhaust before approaching the converter. An experiment following a Box- Behnken design was used to study the effect of engine speed, spark angle, load, relative air/fuel ratio (lambda) and secondary air flow on pre-catalyst temperature. The study suggested the best result for the engine studied was to achieve fast catalytic light-off time was to run engine at 1225 rpm, spark angle of 0 degree BTDC, lambda of 0.82 and load of 0.5 bar BMEP. These settings allowed the remaining fuel to be burned with 5.87 kg/hr of secondary air in the exhaust manifold to achieve a pre-catalytic temperature of 631.1 QC and achieve light-off for all emissions within 17.2 seconds. The results were also used to build a temperature prediction model using the Matlab MBC toolbox and the best available model gave an R2 of 0.9997 by using radial base functions (RBF). However, the optimum conditions still produced cyclic variation in the combustion, giving an average COVimep of 14.8% during the pre-catalytic heating period which caused problems concerning engine smoothness. To derive a greater insight into the mechanisms governing the cyclic variability observed a simulation study was undertaken. The study used a simulation using Ricardo WAVE and Matlab Simulink to allow a detailed representation of some of the principle mechanisms giving rise to cyclic variability under cold start conditions. The study included combustion under rich and lean mixtures and considered the effect of variations of air/fuel ratios and residual gas fraction. As a result, the simulation showed a similar characteristic variability of heat release to that observed experimentally. The validation of the model for heat release showed that the predictions were under estimated by 0.49 % while under lean combustion, there was an under estimation of 2.07%. Both predictions had normally distributed residuals. The model suggested that the residual gas fractions were higher than the limit of 8.8% (under rich fuelling) or 8.0% (under lean fuelling) that was predicted to cause ignition delay to increase significantly and therefore contribute to high cyclic variability. ' An optimisation was carried out by varying camshaft angle in the simulation. The results suggest that retarding the exhaust camshaft position by 4 degrees (EVC 12 degrees BTDC) could reduce COVimep by 63.2% under rich combustion. In contrast, advancing the intake camshaft position suggested that the COVmep can be reduced but more experimental data is required to validate the results because variation of intake camshaft positions had a larger impact on pumping work than varying exhaust camshaft positions. These additional pumping losses result in higher air and fuel flow requirements. In summary, this thesis describes a detailed investigation into the effects of engine calibration on catalyst heating performance. One of the limiting factors in achieving rapid light-off is combustion variability. Extensions have been introduced to an industry standard ID engine simulation to allow realistic cyclic variability to represented and developed. These tools could allow cyclic variability to be considered more rigorously during a calibration exercise.
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Lattimore, Thomas. "Combustion and emissions of a direct injection gasoline engine using EGR." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6677/.
Full textAbstract:
This research has examined the combustion and emissions of a spray-guided direct-injection spark-ignition (DISI) engine using exhaust gas recirculation (EGR). The impact of EGR type, swirl and tumble intake airflows, compression ratio and fuel type were also investigated. EGR addition resulted in significant fuel consumption improvements and differing particulate matter (PM) behaviour depending on the knock limited maximum brake torque (KLMBT) spark advance achieved. When comparing EGR types, cooled EGR achieved the best fuel consumption and cooled EGR after three-way catalyst (TWC) achieved the best gaseous emissions (NOx and HC). Swirl and tumble intake airflows significantly increased fuel consumption. However, these increases could be minimized with EGR addition. Swirl significantly reduced the accumulation mode particulate emissions, providing a potential solution for PM reduction. EGR addition did not significantly affect PM for the swirl and tumble intake airflow conditions. 20%vol 1-butanol addition to gasoline fuel (Bu20) resulted in significant PM reductions at 8.5 bar IMEP. At 7.0 bar IMEP, EGR addition allowed the KLMBT spark timing to be advanced, as the compression ratio was increased. Fuel consumption was improved by 0.4% due to the spark advance and reduced pumping losses, and PM improved because the formation of primary particles was reduced.
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Wang, Chongming. "Combustion and emissions of a direct injection gasoline engine using biofuels." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5402/.
Full textAbstract:
Impact of biofuel (2-methlyfuran, 2,5-dimethylfuran and ethanol) on the performance of a gasoline direct injection engine has been investigated. MF demonstrates better knock resistance properties and faster burning rates compared to those of gasoline. MF has much lower fuel consumptions than ethanol, produces much lower hydrocarbon (HC) and PM emissions than those of gasoline. However NOx emissions from MF are significantly higher than those of gasoline when fuel-optimized spark timings are used, which can be addressed by either retarding ignition timing or using exhaust gas recirculation. MF produce much lower aldehyde emissions compared with gasoline, methanol and ethanol. The majority of HC emissions are unburned fuel. Toluene and benzene are detected in the exhaust however their concentrations are relatively low. Under rich combustion and later injection operating conditions, soot only accounts for a small fraction (<30%) of PM. Soot produced from the combustion of DMF and ethanol is more easily oxidized than gasoline soot due to their unique capsule type oxidation mode, smaller primary and agglomerated particles. PM emissions vary significantly to fuel and injection system. Unlike gasoline, PM emissions from ethanol powered the DISI engine are not sensitive to injection system; a low injector pressure and a bad injector condition have very limited negative impacts on PM emissions.
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Giavis, Konstantinos C. "Catalytic control of individual hydrocarbons from a small utility gasoline engine." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09292009-020311/.
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Rupp, Daniel. "Model-based adaptive air/fuel ratio control for an automotive gasoline engine /." Zürich : ETH, 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18302.
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Godwin, Simon Neil. "Characteristics of a spark-ignition engine fuelled by gasoline and natural gas." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481510.
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Tharp, Ronald S. "Hydrocarbon emissions in a homogeneous direct-injection spark engine : gasoline and gasohol." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44888.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 85).
In order to better understand the effects on hydrocarbon emissions of loading, engine temperature, fuel type, and injection timing, a series of experiments was performed. The effect of loading was observed by running the engine at a higher temperature and more open throttle than would typically be observed at fast idle or low load driving. The effects of coolant temperature, the charge motion control valve, spark timing and rail pressure were tested through holding all other variables constant and sweeping through different injection timing to observe the effect on emissions and power output. A new fuel system was designed to allow for the quick testing of different ethanol blends. The system allowed for comparison testing of an 85% ethanol blend to UTG 91 as a function of coolant temperature and injection timing. Measurement of cylinder pressure and hydrocarbon emissions near the exhaust valve allowed for a better understanding of engine operation and the effect of using high ethanol content fuels. Initial testing was also done on 15% and 40% ethanol blends. The results revealed that engine emissions decrease as a function of reduced loading and higher engine temperatures. Sweeps of injection timings for all fuels demonstrated high hydrocarbon emissions for earlier injection timings which fell as injection timing was retarded. A secondary peak was observed in hydrocarbon emissions for an injection timing of approximately 150 CAD aTDC intake. Analysis of rate of fuel injection vs. indicated power revealed a steady decrease in indicated efficiency as injection timing was retarded up to 120 CAD aTDC Intake and then a slow rise in efficiency as the timing was further retarded. The exact causes of the decrease in engine efficiency are unknown; however, possible explanations involve increased heat transfer from the cylinder and piston, fuel loss, and inefficient combustion due to impingement on cold surfaces.
by Ronald Tharp.
S.M.
30
Demnitz, Simon. "Investigating the feasibility of characterising gasoline autoignition using a motored engine apparatus." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/14645.
Full textAbstract:
Development of a predictive octane model is a potentially useful tool for designing fuel blends for meeting octane specifications. One of the approaches adopted is through chemical kinetic modelling of the autoignition properties of constituent compounds. The results obtained from models, however, are dependent on experimental data for validation. It was the intention of this thesis to provide empirical data that could be used confirm a recently proposed autoignition model based upon the results obtained from chemical kinetics modelling. Motored engines have been used extensively for the investigation of autoignition properties of fuels. They are useful in interpreting results from conventional ignition delay measuring systems as well as giving practical insight into the process of autoignition in spark ignition engines. The conditions required for autoignition reactions to take place are easily produced in a motored engine with a suitable compression ratio. A single cylinder engine was modified so that the inlet conditions could be adjusted and n-heptane was tested in the device. Fuelling was controlled with an injection system which was calibrated for n-heptane use in the engine. A range of inlet conditions were determined that would enable peak conditions in the engine to result in autoignition of the fuel. The autoignition data was then used in describing the ignition delay characteristics of the fuel and the range of interest, the so called negative temperature coefficient region. Autoignition experiments were performed in the engine and the data was analysed by the comparison of measured autoignition reactions with predicted reaction times; the predictions were calculated using the new empirical autoignition model. Direct analysis of the model resulted in good correlation of measured and predicted overall autoignition reaction times, with improved correlation of cool flame reaction times with initial temperature adjustment. Modification of initial temperature values in the indirect model application (whereby traces were generated using an engine model with autoignition prediction capabilities) resulted in similar observances. These initial results led to the conclusion that the temperature and Arrhenius parameter adjustments necessary to obtain a perfect fit in the autoignition model were indicative of errors involved in the temperature measurement or in the fuel metering. Recommendations for further work on the engine would be the investigation of a dynamometer system that would be free from noise transmission during operation and that would enable experimentation with lower engine speeds. Further work on the inlet system would be the installation of shielded thermocouples and a quicker acting heater controller. A fundamental change in fuel metering calibration is required. Further recommendation is that a variable compression ratio engine should be used to enable the attainment of a wider range of readings for fuel characterisation and possibly eradicate the problems experienced with fuelling.
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St, Hill Nicholas. "An investigation of flow processes in a dual-intake motored engine in relation to gasoline direct injection engine operation." Thesis, King's College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402175.
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Oakley, Aaron John. "Experimental investigations on controlled auto-ignition combustion in a four-stroke gasoline engine." Thesis, Brunel University, 2001. http://bura.brunel.ac.uk/handle/2438/5309.
Full textAbstract:
The effects of air and exhaust gas dilution on the CAI combustion of a range of fuels including three gasoline compositions, four primary reference fuels, and two alcohols are experimentally investigated using a single cylinder research engine. Two of the three gasolines tested are manufactured from standard gasoline during engine operation by a novel fuel system, designed to improve the performance of both controlled autoignition and spark ignition engines. A series of experimental tests are performed to establish the satisfactory combined air and exhaust gas dilution regions for each fuel. Detailed in-cylinder pressure and exhaust gas speciation measurements are taken, and the fuels are compared and contrasted for their performance in terms of power output, fuel consumption, and harmful exhaust emissions. Results show that alcohol fuels are superior to hydrocarbon fuels for controlled autoignition combustion because their autoignition characteristics are less affected by the presence of exhaust gas species. Furthermore, the timing of autoignition is shown to be of minor importance for achieving efficient and stable controlled autoignition combustion, contrary to widely held beliefs. In addition, the novel fuel system is developed and commissioned for use on a single cylinder research engine operating with a spark ignition system. The two gasoline fuels produced by the system are evaluated individually for their knocking combustion characteristics over a range of compression ratios and spark advances. Results from these tests indicate that the fuel system used in conjunction with a specially modified production engine may allow the normal compression ratio of that engine to be increased by up to 1.0, increasing its efficiency.
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Reveille, T. "Study of fuel injection and mixture formation for a gasoline direct injection engine." Thesis, Cranfield University, 2005. http://hdl.handle.net/1826/4288.
Full textAbstract:
Future requirements for lower automotive emissions have lead to the development of
new internal combustion (IC) engine technologies. Gasoline Direct Injection (GDI), for
example, is one of these promising new IC engine concepts. It offers the opportunity of
increased efficiency through unthrottled operation. However, the realisation of this
concept is critically dependent on the in-cylinder mixture formation, especially in the
late injection/lean operation mode. Ideally, this would require a precise stratification of
the in-cylinder fuel-air mixture in 3 distinct zones: an ignitable pocket located at the
spark plug, surrounded by a stoichiometric mixture of fuel and air, encompassed by air.
To enable this stratification, the GDI concept utilises advanced injector technology.
Phase Doppler Anemometry (PDA), Planar Laser-Induced Fluorescence (PLIF) and the
combination of PLIF and Mie scattering in the Laser-Sheet Dropsizing (LSD)
technique, have been applied to sprays in the past to obtain dropsize information and
study the mixture formation process. These new GDI sprays are denser, their droplet
sizes are smaller and they evaporate faster, and as such, place us at the limit of the
validity of these measurements techniques.
The diagnostics were applied to a GDI spray in a pressure vessel for realistic in-cylinder
conditions, ranging from supercooled to superheated environments. Tracer evaporation
issues in the PLIF technique were resolved by using a dual tracer system. The study
showed that the LSD technique provided good quantitative data in low evaporation
regimes. In highly evaporating regimes, the technique still gave reliable dropsize data
for the early stages of the injection, but was limited afterwards by vapour-phase
contribution to the fluorescence signal. Variations between PDA data and LSD results
also suggested a deviation of the Mie scattering signal from the assumed d2 dependence.
This was further investigated and was found to be true for small droplets (d/?. <0.2). This
source of error might be improved by using a different observation angle. High density
seriously compromises the accuracy of PDA, whilst its effect through multiple
scattering is of second order for the LSD technique. In low evaporating regimes, LSD has the overall advantage of being a 2-D measurement
technique, and will yield data with a maximum error of 30% in dense parts of the spray
where PDA data is totally unreliable. If the spray evaporates quickly, PLIF by itself is
an appropriate tool for following the air-fuel mixture, because short droplet lifetimes
limit the 2-phase flow behaviour of the spray.
Particle Image Velocimetry (PIV), the LSD technique and equivalence ratio LIF
measurements were applied to a BMW single cylinder optical GDI engine. The early
injection operation showed no particular issues. However, the results obtained in the late
injection highlighted the poor mixing and inappropriate stratification.
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Hussain, Nibras. "The Dynamic Behaviour of a Nitrogen Oxide Trap for Direct Injection Gasoline Engine." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487971.
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Kalian, Navin. "Investigation of CAI/SI operations ina a four-cylinder direct injection gasoline engine." Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/5482.
Full textAbstract:
A four-cylinder, four-stroke, gasoline engine with direct injection fuel was commissioned and used to achieve CAI combustion. CAI combustion was achieved by employing short-duration, low-lift camshafts and early exhaust valve closure. Trapping sufficient volumes of exhaust residual provided the necessary thermal energy needed to initiate auto-ignition. The effects of valve opening durations on the CAI operation range were investigated at different air/fuel ratios, valve timings and injection timings. Furthermore the effect on engine performance, exhaust emissions, fuel consumption and combustion characteristics were also investigated. Methods which could be used for CAI combustion region enlargement were also studied. These included spark-assisted CAI at different EVC timings and valve durations, CAI operation at 2000 rpm and CAI combustion at late fuel injection timings
36
Tu, Powen. "Numerical and experimental study of spray characteristics in the gasoline direct injection engine." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6687/.
Full textAbstract:
In the recent development of the gasoline combustion engine, direct injection (DI) technology has been widely used to improve fuel economy and reduce exhaust emissions. Because of the limitation of experimental techniques, the transportation of fuel within the GDI injector nozzle hole and near-field spray is not well understood. In this study, computational fluid dynamics (CFD) modelling and direct coupling of the Euler in-nozzle flow model with the Lagrangian spray model are employed to investigate the effect of different nozzle geometrical designs on the GDI spray characteristics. Euler modelling of the inside-nozzle flow reveals that a round nozzle inlet significantly increases the mass flow rate and nozzle exit velocity. A longer internal nozzle wall length results in a decrease in mass flow rate and larger droplet distribution in the nozzle near-field. At the nozzle exit, the nozzle flow parameters obtained from the Euler-based study are implemented as initial conditions for the subsequent Lagrangian-based spray model. The direct coupled Euler–Lagrangian approach is then compared with the Kelvin-Helmholtz-aerodynamic cavitation–turbulence (KH-ACT) model and the Max Planck Institute (MPI) model. The effects of injection and ambient pressure on spray characteristics are separately investigated by experimental and numerical approaches. Three different fuels, iso-octane, DMF and ethanol, are investigated using the MPI-CAB model and experimental approaches in order to gain comprehensive insight into the effect of fuel properties on spray characteristics.
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Fennell, Daniel Alexander. "Exhaust gas fuel reforming for improved gasoline direct injection engine efficiency and emissions." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5439/.
Full textAbstract:
The thesis investigates how exhaust gas fuel reforming, also known as reformed exhaust gas recirculation (REGR), may benefit direct injection gasoline (GDI) engine efficiency and emissions. REGR is a thermochemical process that has potential for efficiently producing hydrogen-rich gas onboard a vehicle by using waste exhaust energy to promote endothermic reforming of hydrocarbon fuels. Partially fuelling a gasoline engine with hydrogen generally improves engine thermal efficiency. The experimental research begins by simulating REGR on single- and multi-cylinder GDI engines, which indicates that REGR can increase engine thermal efficiency by up to 9% and reduce NOx by up to 96%. Particulate matter (PM) measurements reveal that REGR significantly reduces PM number and mass emissions, beyond that achieved by EGR. Further experiments with a full-scale prototype exhaust gas fuel reformer integrated with the multi-cylinder GDI engine demonstrate improved fuel efficiency at a wide range of engine conditions, by 8% for conditions typical of motorway driving. The reforming process is observed to be overall endothermic when the exhaust temperature is above 650°C, and the reformed fuel enthalpy is increased by up to 21% in these experiments. The results demonstrate that REGR can simultaneously increase engine thermal efficiency, and reduce gaseous and PM emissions.
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Lu, Pin. "Investigation of gasoline partially premixed combustion in a single cylinder optical diesel engine." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/10463.
Full textAbstract:
Gasoline Partially Premixed Combustion (PPC) was investigated in a single cylinder optical diesel engine. The PPC operation was achieved with a combination of high dilution and higher intake charge temperature at part-load conditions using Primary Reference Fuel (PRF). The relative air/fuel ratio (λ) was set to 2.3 and the EGR rate at 22%. Split injections of three fuel distribution strategies (50:50, 70:30 and 30:70) were studied. In addition, the effect of injection pressure (900 and 1200 bar) was investigated for each injection timing. The emission and performance of the gasoline PPC operations were then compared with those of the baseline diesel combustion operation. Based on the thermodynamic analysis of the engine performance, detailed in-cylinder studies were carried out by means of optical techniques. The high speed imaging technique was employed to observe the fuel spray development and combustion processes. A simultaneous Mie-LIF technique was then developed and utilized for the visualization of fuel liquid and vapour formation.
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Hwang, Gong-Do, and 黃公度. "aerosol in gasoline engine emission." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/71528892050476306769.
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Tzu-Heng, Wu, and 吳子恒. "Neuro-Fuzzy Clustering Analysis of Gasoline Engine." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/54441540980303749415.
Full textAbstract:
碩士南台科技大學
機械工程系
91
Clustering analysis has been widely used in data classification is due to it can extract the representative characteristics of cluster. It can partition the given set of datum into various characteristic cluster based on the similarity degree of datum. Clustering analysis is divided into hierarchical and nonhierarchical methods, the hierarchical method uses the nested structure to achieve the classifying purpose, and the nonhierarchical method applies various validity indices to determine the best number of clusters. In this thesis, we employ various clustering algorithms and validity indices to discuss the application of data classification. The compared results indicate that , and validity indices have best adaptation in decision of number of clusters. Because gasoline engine is a nonlinear system with uncertainties, it is ineffective to apply analytical approach to construct an engine dynamic model. Therefore, we attempt to apply the fuzzy clustering method to obtain the local optimal results with clustering analysis and various validity indices. The clustering results are used to construct a clustering-based estimator to estimate the output of gasoline engine under various operating conditions. The experimental results indicate that the clustering-based estimator can correctly predict the unmeasured outputs.
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陳聖洲. "Neuro-fuzzy Fault Diagnosis for Gasoline Engine." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/98608109698686694169.
Full textAbstract:
碩士南台科技大學
機械工程系
91
In this work, the neuro-fuzzy algorithm is applied to the fault diagnosis of gasoline engine from the sensing system. The sensing voltages are normalized before feeding into the neural network. By using steepest descent method the adaptation laws of parameters of fuzzy set and output of the inference rules are achieved. Output parameters represent the possibility of the fault source. To aim directly at the faults of air flow sensor and O2 sensor, the fault conditions of overestimated or underestimated air flow and dense O2 density are detected by the proposed diagnostic system. In this thesis, the study is divided into two parts: 1. Numerical simulation: The engine state variables are collected when air-flow sensor, intake manifold pressure sensor or mass air flow sensor has fault. The collected state variables are used to build the database for the diagnostic system. 2. Experiment: The engine state variables are collected when O2 sensor, injecting time, advanced ignition angle or intake manifold pressure sensor has fault. The collected state variables are used to build the database for the diagnostic system. Through the experimental results, the effectiveness of the proposed fault diagnosis system is verified. The above results show that the diagnostic system with neuro-fuzzy technique can exactly determine the fault of sensor. The construction of diagnostic system can be used as a reference of gasoline engine of sensor fault diagnosis.
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Silva, João Filipe Matos. "Software for a gasoline internal combustion engine." Master's thesis, 2010. http://hdl.handle.net/10216/63302.
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Tsai, Jhong-Sian, and 蔡忠憲. "Effect of Hydrogen on Gasoline Engine Performances." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/66446181617718206354.
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碩士崑山科技大學
機械工程研究所
100
In this study, the proton exchange membrane hydrogen generator was used to carbon reduction and combustion added for gasoline engine and reducing engine pollutant emissions. In order to enhance vehicle performance and reduce exhaust pollutants, the hydrogen was added to engine as an auxiliary fuel. The experimental projects were planning at two steps. The first step was modified gasoline engine intake system and convergence with the hydrogen manufacturing machine, induction hydrogen to clean the combustion chamber carbon deposits. The second step was induct different proportions of hydrogen/gasoline mixture, the combustion characteristics were recorded and engine was operated at different engine load conditions. Experimental results show that the deposit was burned after higher temperature combustion, the surface carbon deposit were removed. The emissions were also lower than the original gasoline. For engine performance tests, the combustion pressure and brake horse-power were increase for increasing the amount of hydrogen induction. For emissions tests, the emission was increased at low speed and low load for incomplete mixing. As engine speed increased,hydrogen feed rate was increased, CO, HC, NOx, were then reduced. At high load and high speed conditions, the CO, HC, NOx were increased and CO2 was decreased.
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Silva, João Filipe Matos. "Software for a gasoline internal combustion engine." Dissertação, 2010. http://hdl.handle.net/10216/63302.
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Zou, Yung-Jing, and 鄒永靖. "Investigation and Analysis of Engine Efficiency for 2.2L Four Strokes Gasoline Engine." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69p735.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系所
102
In recent years, energy shortage and greenhouse effect are major issues in the world, and the technology of energy-saving engine are advancing, in order to study and reduce fuel consumption, and improve each efficiency of the engine. The first step is survey paper to build the each benchmark of efficiency. Experiment the target engine and calculate the flow coefficient, thermal efficiency, mechanical efficiency, volumetric efficiency and combustion efficiency. Final to comparative the data of target engine with benchmark, and find out the advantage and disadvantage of the target engine. This research firstly executes flow coefficient test of intake and exhaust manifold. From the results, the flows of intake and exhaust manifold are lower than the benchmark, that causes poor volumetric efficiency. The target engine has been experimented, and then engine efficiencies are calculated from the experiment results. FMEP (Friction Mean Effective Pressure) of target engine is higher than international benchmark average, representing friction loss higher than normal standard. By comparison of brake thermal efficiency performance, target engine has caught the international benchmark standard. Combustion efficiency is higher than 95% at middle and low load, but decrease to 70% at high load caused by high concentration air-fuel ratio. From combustion analysis results, Pmax occurs 6~40 degrees at each load, seems invalid. By the heat release rate analysis, the heat release rate is obviously over advanced at low load. 50% of fuel is consumed before compress top dead center, causing too much work waste to push piston before top dead center. At high load, the heat release rate is obviously over retarded, the work is unease to be done. Therefore, if spark advance could be regulated, the performance of engine torque and thermal efficiency could be improved.
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Brown, Greg. "Performance of a partially stratified-charge gasoline engine." Thesis, 2003. http://hdl.handle.net/2429/14072.
Full textAbstract:
Stratified-charge lean burn engines have shown promise in their ability to reduce certain emissions and improve fuel economy while still providing acceptable driveability and performance. A local charge stratification process, the Partially Stratified-Charge (PSC) concept, has been developed at the University of British Columbia in an attempt to further improve lean burn operation. In the PSC engine, a lean homogeneous mixture is inducted into the combustion chamber and is compressed during the compression stroke. Just prior to the spark, a small amount of fuel is injected into the combustion chamber in the vicinity of the spark plug. This produces a rich pocket that can be ignited more easily and facilitates the combustion of the remaining lean homogeneous mixture. The main objective of the research presented here was to implement a PSC system on a gasoline engine and examine the performance of the PSC system relative to its homogeneous fuelled counterpart. Two different PSC systems were tested. The first system was based on a natural gas PSC system developed during previous work while the second system was a new gasoline PSC system developed specifically for this research. Analysis of the performance and emissions results for the natural gas PSC studies showed significant advantages over conventional lean burn and stoichiometric homogeneous-charge operation. The most notable improvement was up to a 15% extension in the relative air-to-fuel ratio (λ). Through this extension of the lean limit, the useable range of brake mean effective pressure was expanded, by up to 20%, when using PSC. A reduction in nitrogen oxide emissions and an increase in total unburned hydrocarbons also accompanied this extension of the lean limit. In-cylinder pressure data analysis demonstrated significantly higher peak in-cylinder pressures and shorter ignition delays with PSC. Throttled tests with the natural gas PSC system revealed the potential to reduce nitrogen oxide emissions, carbon monoxide emissions and brake specific fuel consumption over stoichiometric homogeneous charge operation. Improvements in PSC volumetric efficiency of up to 15% and 5% were realised compared to stoichiometric homogeneous and conventional lean burn operation, respectively. Extensive experiments were also undertaken with a gasoline PSC system, however, performance improvements, though expected, were not observed. Examinations of the gasoline PSC system suggested that there were some challenges in achieving local charge stratification in the vicinity of the ignition source. These results implied that further optimisation, and perhaps a redesign of the gasoline PSC system, would be required to fully realise the performance benefits demonstrated with the natural gas PSC system.
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Lin, Wu Hsing, and 林武興. "Test and Simlation of Turbocharger the Gasoline Engine." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/13655992993962920119.
Full textAbstract:
碩士中華工學院
航空太空工程研究所
85
This study investigates performance of the turbocharged gasoline engine.The improvements in engine torque, power, and emissions are studied.The engine simulation code BOOST is also used to simulate the overallengine performance in the present study.Experimental results show that the turbocharged engine has the bestimprovement with the boost pressure 1.4 ~ 1.5 bars. With this range ofthe boost pressure, the engine can be operated with a higher air-fuelratio and also gives low CO and HC emissions. The simulation results give good agreement in the engine torque and powerfor the naturally-aspirated conditions. However, only fair agreement isobtained for the turbocharged conditions.
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Ye, Rung-Feng, and 葉榮豐. "The Performance Analysis and Test of Ethanol-Gasoline Engine." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36967160469109002615.
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Chen, Chia-hao, and 陳家豪. "Design and Analysis of a Gasoline Direct Injection Engine." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/v3gkjx.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
99
CFD software (STAR-CD) was used to simulate the combustion mechanism of 4-strokes motorcycle engine. Fuel injection arrangements inside a cylinder during intake and compression strokes were studied through computer simulation. Fan-shaped and spray injector have been studied and air fuel mixture inside the engine cylinder has been analyzed in homogeneous and stratified charges. In homogenous charge, injector location and injection angle were varied to study droplet size and oil concentration distribution. In stratified charge, piston concave crown and spark plug location were determined based on oil concentration distribution. Sauter mean diameter (SMD) and uniform concentration techniques were used to compute droplet size formed by different injector locations and injection angles. When fan-shaped injector was placed at the the center of the cylinder, better uniform concentaration and smallest droplet size were found at 10 degrees injection angle. While the injector was placed at the center and 0 degree, uniform concentration was observed but droplet size was larger than that of 10 degrees. However for the case of injector placed near the rim of the cylinder and -21 degrees, both concentration distribution and droplet size were worst of the cases studied here. Similar results were obtained when spray injector was investigated. Piston concave crown model No. 3 showed better spark plug focus and provided concentrated droplet at the center of the cylinder head.
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CHAO, CHI-SHEN, and 趙繼生. "Spark Timing Analysis of Gasoline Direct Injection Turbocharged Engine." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/dsx92w.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系
107
This study analyzes the experimental data of an original controller for a gasoline direct injection turbocharged engine. Use CA (Crank Angle) at the maximum cylinder pressure to estimate the MBT (maximum braking torque) position of the spark timing, and carrying out the engine experiment after the design. For the common operation range of the plug-in hybrid electric vehicle, the experiment is performed from engine speed 1200 rpm to 2800 rpm, with the partially open throttle, stoichiometric air-fuel ratio, MBT ignition timing to measure engine performance, fuel consumption and pollution data. The spark timing data after design has the same trend as the actual calibration result in the experiment, indicating that can advance the spark timing in advance and the maximum pre-cylinder pressure within a reasonable range. The results show the maximum improvements of brake torque is up to 14.3%; and the maximum improvement of BSFC (brake specific fuel consumption) is 23.6%; pollution emission data will be changeable under the different combustion conditions and operating conditions. The maximum improvement of CO is 67.5%, and combustion efficiency of some experimental points is significantly improved after adjusting to the MBT position.