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Toulson, Elisa. "Applying alternative fuels in place of hydrogen to the jet ignition process /". Connect to thesis, 2008. http://repository.unimelb.edu.au/10187/3532.
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Islam, Muhammad Aminul. "Microalgae: An alternative source of biodiesel for the compression ignition (CI) engine". Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/79551/4/Muhammad%20Aminul%20Islam%20Thesis.pdf.
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This thesis is a comprehensive study of microalgae biodiesel for the compression ignition engine. It examines microalgae growing conditions, the extraction process and physiochemical properties with a wide range of microalgae species. It also evaluates microalgae biodiesel with regards to engine performance and emission characteristics and explains the difficulties and potentiality of microalgae as a biodiesel. In doing so, an extensive analysis of different extraction methods and engine testing was conducted and a comprehensive study on microalgae biodiesel is presented.
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Imran, Shahid. "Experimental and numerical investigation of performance and emissions in compression ignition engines with alternative fuels". Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8505.
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The experimental investigation in this work concerns the compression-ignition (CI) engine combustion process both in normal operation and dual-fuel operation. There is a bulk of literature reporting thermal efficiencies, brake specific fuel consumption (BSFC) and emissions under single and dual fueling conditions in CI engines. Most of the studies lack the full implications of changing load (power output) and speed on these performance indicators. The studies are either restricted to various loads/powers at one engine speed (neglecting the effect of engine speed) or one or two load/power conditions at various speeds (neglecting load variations). There is a scarcity of full engine maps in the open literature (these are the full contours of thermal efficiency or BSFC plotted throughout the power versus speed range of the engine, or the torque versus speed range of the engine). This thesis provides performance and emissions maps for a CI engine using two different fuels (diesel and rapeseed methyl ester used as single fuels) and two gaseous fuels (natural gas and hydrogen) used with two different pilot fuels (diesel and rapeseed methyl ester ) under what is termed dual fueling mode. A novel approach is used to present the performance and emissions over the entire engines operational range. The results are presented as iso- contours of thermal efficiency, volumetric efficiency and brake specific NOX, specific HC and specific CO2 on a power-speed graph throughout the operating range of the engine. Many studies conclude that the emissions, particularly NOX during dual fueling are expected to form in the spatial region around the pilot spray. This region is expected to be subjected to high localised temperatures as the equivalence ratio is close to stoichiometric, thus maximising heat release from combustion. The effect of changing the pilot fuel quantity on performance and emissions is rarely reported. This study addresses this scarcity in the literature and investigates the effect of changing the pilot fuel quantity and type on various combustion and emission parameters. Diesel and rapeseed methyl ester (RME) have been used as pilot fuels for both the natural gas as well as hydrogen and three different pilot fuel settings have been employed for each of the gaseous fuels. The effect of using a different pilot fuel quantity to achieve the same brake mean effective pressure (BMEP) for the two gaseous fuels has been analysed and compared. This thesis also includes a chapter on the computational modeling of the engine esmissions. This study uses combinations of different spray and combustion models to predict in-cylinder pressure, rate of heat release and emissions. The approach employs two combustion models: Unsteady Flamelet Model (UFM) with PDF method and Finite Rate Chemistry (FRC) with stiff chemistry solver implemented through In-Situ Adaptive Tabulation (ISAT) algorithm. Two spray models used includeWAVE and Kelvin Helmohltz Rayleigh Taylor (KHRT) spray models. The UFM coupled with KHRT spray model has been used to predict NOX, CO and CO2 emissions. The model captures the emissions trends well. In-cylinder contours of O2, NO and mass average temperature have also been presented. A chemical mechanism of n-heptane with 29 species and 52 reactions has been used.
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Cambridge, Shevonn Nathaniel. "The effect of compression ratio on emissions from an alcohol-fueled engine". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09122009-040220/.
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Surawski, Nicholas C. "An investigation of gaseous and particulate emissions from compression ignition engines operated with alternative fuels, injection technologies, and combustion strategies". Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/54194/1/Surawski_Thesis_2011.pdf.
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Whilst the compression ignition (CI) engine exhibits many design advantages relative to its spark ignition engine counterpart; such as: high thermal efficiency, fuel economy and low carbon monoxide and hydrocarbon emissions, the issue of Diesel Particulate Matter (DPM) emissions continues to be an unresolved problem for the CI engine. Primarily, this thesis investigates a range of DPM mitigation strategies such as alternative fuels, injection technologies and combustion strategies conducted with a view to determine their impact on the physico-chemical properties of DPM emissions, and consequently to shed light on their likely human health impacts. Regulated gaseous emissions, Nitric oxide (NO), Carbon monoxide (CO), and Hydrocarbons (HCs), were measured in all experimental campaigns, although the major focus in this research program was on particulate emissions...
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Bodisco, Timothy Alexis. "In-cylinder pressure and inter-cycle variability analysis for a compression ignition engine : Bayesian approaches". Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/62064/11/Timothy_Bodisco_Thesis.pdf.
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This thesis introduced Bayesian statistics as an analysis technique to isolate resonant frequency information in in-cylinder pressure signals taken from internal combustion engines. Applications of these techniques are relevant to engine design (performance and noise), energy conservation (fuel consumption) and alternative fuel evaluation. The use of Bayesian statistics, over traditional techniques, allowed for a more in-depth investigation into previously difficult to isolate engine parameters on a cycle-by-cycle basis. Specifically, these techniques facilitated the determination of the start of pre-mixed and diffusion combustion and for the in-cylinder temperature profile to be resolved on individual consecutive engine cycles. Dr Bodisco further showed the utility of the Bayesian analysis techniques by applying them to in-cylinder pressure signals taken from a compression ignition engine run with fumigated ethanol.
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Lezzar, Balahouane. "Contribution à l'étude de la combustion et des limites de fonctionnement dans un monocylindre à taux de compression variable alimenté au méthane, au gaz de groningue et avec un mélange méthane-éthane". Valenciennes, 1987. https://ged.uphf.fr/nuxeo/site/esupversions/0d1a9c0a-0df4-4fab-8206-316c90031798.
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Bari, Saiful. "Alternative fuels in diesel engine". Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303788.
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Kenny, Wilhelm Jordaan. "Development of an engine testing facility for spark ignition engine fuels". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80043.
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Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This thesis comprises of the development of a facility were spark ignition engine fuels can be tested. Development of the facility included the installation of a standard spark ignition engine, an engine dynamometer, control and monitoring equipment, control and monitoring software, and an in-cylinder pressure measurement setup. The system was tested using petrol as well as a petrol-ethanol blend. The results indicated good accuracy and repeatability of the system. Analysis of the performance and combustion of the petrol-ethanol blend showed no significant difference in comparison to the petrol fuel. The petrol-ethanol blend showed a slight increase in oxygen content and fuel consumption as well as an increase in CO2 emissions and a decrease in CO emissions. During the project, a comparison was also made between the performance of fibre optic transducers and a piezoelectric transducer. It was found that the fibre optic transducers performed similarly to the piezoelectric transducer during low engine load conditions. At high load conditions however, the fibre optic transducers were not able to produce the same accuracy as the piezoelectric transducer.
AFRIKAANSE OPSOMMING: Hierdie tesis bestaan uit die ontwikkeling van 'n fasiliteit waar brandstowwe vir 'n vonkontsteking binnebrandenjin getoets kan word. Ontwikkeling van die fasiliteit sluit in die installering van 'n standaard vonkontsteking binnebrandenjin, 'n enjin rem, beheer en monitering toerusting, beheer en monitering sagteware, en 'n insilinder drukmeting opstelling. Die fasiliteit is getoets met suiwer petrol sowel as 'n petrol-etanol mengsel. Die resultate het hoë vlakke van akkuraatheid en herhaalbaarheid getoon. Ontleding van die werksverrigting en verbranding van die petrol-etanol mengsel het geen beduidende verskil getoon in vergelyking met die suiwer petrol brandstof nie. Die petrol-etanol mengsel het 'n effense toename in suurstofinhoud, brandstofverbruik, sowel as CO2 vrylating en 'n afname in CO vrylating getoon. Tydens die projek is 'n vergelyking getref tussen die akkuraatheid van optiese vesel drukmeters en 'n piësoëlektriese drukmeter. Daar is bevind dat die akkuraatheid van die optiese vesel drukmeters soortgelyk is aan die piësoëlektriese drukmeter gedurende lae enjin lastoestande. By hoë las omstandighede was die optiese vesel drukmeters egter nie in staat om dieselfde akkuraatheid as die piësoëlektriese drukmeter te handhaaf nie.
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White, Timothy Ross Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Simultaneous diesel and natural gas injection for dual-fuelling compression-ignition engines". Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/25233.
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The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.
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Baslamisli, Ufuk. "Helicopter Turboshaft Engine Ground Preformance With Alternative Fuels". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614098/index.pdf.
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In recent years, extensive studies on alternative fuels have been conducted to find environmentally friendly, economically feasible fuels due to finite petroleum sources, environmental and economical reasons. In this thesis, effects of alternative fuels on engine performance and exhaust emission are studied experimentally. Cold and reacting tests have been performed. Volumetric flow rate, discharge pressure are measured according to different pump speed. Droplet diameters, droplet distribution, spray cone angle and two dimensional velocity distribution from combustor fuel nozzle are determined by IPI and PIV technique. The comparative performance of alternative fuels and JET A-1 are investigated by atmospheric combustion tests and experimental turbojet tests in terms of exhaust gas temperatures, emissions, combustion chamber efficiency. Emissions, combustion chamber exit temperature profile, power turbine inlet and exhaust gas temperatures, effects of fuels on engine performance are observed and measured in detail at RR Allison 250 C-18 turbo-shaft engine.
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Rydalch, Andrew J. "Ignition delay properties of alternative fuels with Navy-relevant diesel injectors". Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42715.
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Approved for public release; distribution is unlimitedIn support of the Navy’s Green Fleet Initiative, this thesis researched the ignition characteristics for diesel replacement fuels used with Navy-relevant fuel injectors. A constant-volume combustion chamber was used to simulate Top-Dead-Center conditions of a diesel engine using an ethylene-air preburn with appropriate make-up oxygen. The injection conditions ranged from temperatures of 1,000 K to 1,300 K and densities has high as 14.8 kg/m3. Hydrotreated renewable diesel (HRD) and direct sugar-to-hydrocarbon (DSH) fuels were injected into the combustion chamber using a Sturman research injector, a Yanmar injector, and an Electro Motive Diesel (EMD) injector. The primary means of data collection was optical emission imaging of laser induced fluorescence of the fuel and broadband emission of the combustion event. The ignition delay was determined using high speed imaging at 50 kHz to determine the time delay between start of injection and start of combustion. The results of the study show that the ignition delay characteristics for the F-76/HRD 50/50 blend are compatible with those of conventional F-76 diesel fuel for both the Yanmar and EMD injectors at the conditions tested. The ignition delay characteristics of the F-76/DSH 50/50 blend fuel for the Yanmar injector were also compatible with those of F-76.
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Bundu, Mohamed Maurie. "Investigation of the performance of a spark ignition engine with gaseous fuels". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/MQ31551.pdf.
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Negrete, Justin E. "Effects of different fuels on a turbocharged, direct injection, spark ignition engine". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59952.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 65).
The following pages describe the experimentation and analysis of two different fuels in GM's high compression ratio, turbocharged direct injection (TDI) engine. The focus is on a burn rate analysis for the fuels - gasoline and E85 - at varying intake air temperatures. The results are aimed at aiding in a subsequent study that will look at the benefits of direct injection in turbocharged engines, ethanol's knock suppression properties, and the effects of ethanol concentration in gasoline/ethanol blends. Spark sweeps were performed for each fuel/temperature combination to find the knock limit and to assess each fuels' sensitivity to spark timing and temperature. The findings were that E85 has lower sensitivity to spark timing in terms of NIMEP loss for deviation from MBT timing. A 5% loss in NIMEP was seen at 3° of spark advance or retard for gasoline, whereas E85 took 5' to realize the same drop in NIMEP. Gasoline was also much more sensitive to intake air temperature changes than E85. Increasing the intake air temperature for gasoline decreased the peak pressure, however, knock onset began earlier for the higher temperatures, indicating that end-gas autoignition is more dependent on temperature than pressure. E85's peak pressure sensitivity to spark timing was found to be about 50% lower than that of gasoline and it displayed much higher knock resistance, not knocking until the intake air temperature was 130°C with spark timing of 30° bTDC. These results give some insight into the effectiveness of ethanol to improve gasoline's anti-knock index. Future experiments will aim to quantify charge cooling and anti-knock properties, and determine how ethanol concentration in gasoline/ethanol blends effects this knock suppression ability.
by Justin E. Negrete.
S.B.
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Kim, Jong-Woo. "Flow, combustion and emissions in a four-valve spark-ignition engine fuelled by compressed natural gas". Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8064.
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Mozafari-Varnusfadrani, Aliasghar. "Predictions and measurements of spark-ignition engine characteristics using ammonia and other fuels". Thesis, Queen Mary, University of London, 1988. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1582.
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The project reported here involves the development of a computer model for determining the characteristics of a spark-ignition engine. The model incorporates detailed consideration of the combustion process -and includes calculations for heat transfer between the contents of the engine combustion chamber and the containing surfaces. Composition changes are taken account of by considering thermodynamic equilibrium of the chemical species that might be present during the combustion and expansion processes. In the case of ammonia, the equilibrium composition is also considered during the compression process. The model has been used to predict the performance of an engine using the following fuels: gasoline (represented by iso-octane in the model), methanol, propane and ammonia. These provide a wide range of properties, air fuel ratios for complete combustion and combustion characteristics so as to give an increased range for testing the validity of the model. Calculations have been performed for a wide ranges of compression ratio and air-fuel ratio for each fuel. Measurements have been made, using the same fuels, in a single cylinder Ricardo E6 engine fitted with a spark ignition cylinder head and fuel supply and metering systems suitable for the four fuels. For a constant speed of 2000 r/min the compression ratio was varied over its appropriate range for each fuel. For each compression ratio the air fuel ratio was varied. Measurements included speed, compression ratio, fuel and air flow rates, dynamometer load, and exhaust gas composition. (carbon dioxide, carbon monoxide, oxides of nitrogen, oxygen, and hydrocarbons). All measurements were for optimised spark timing. The results are compared with predictions and with published work.
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Daniel, Ritchie Lewis. "Combustion and emissions performance of oxygenated fuels in a modern spark ignition engine". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3675/.
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The combustion and emissions performance of oxygenated fuels has been investigated in a modern direct-injection spark-ignition (DISI) engine. In particular, the new biofuel candidate, 2,5-dimethylfuran, otherwise known as DMF, has been assessed as a future automotive fuel against ethanol, the most commercially accepted spark-ignition (SI) biofuel. When operating with DMF, the engine performance and emissions are less sensitive to changes in key control parameters than with gasoline. This allows a wider window for improving performance and/or reducing emissions. The relevance of modern injection strategies to increase performance or efficiency has also been assessed when using DMF. The use of split-injection at full load is shown to be less beneficial than with gasoline. Novel fuel preparation techniques have been investigated by comparing externally supplied gasoline-biofuel blends (conventional method) to internally mixed, dual-injection blends. This new mode presents an avenue for optimising oxygenated fuels with a low heat of vaporization, such as DMF and n-butanol; low blends with gasoline (≤25% by volume) are more efficiently utilised than in external blends. Furthermore, the particulate matter (PM) emissions can be reduced with dual-injection because gasoline is supplied through PFI. The unlegislated emissions when using DMF have been benchmarked against gasoline and compared to other oxygenated fuels. In particular, the emissions of the major carbonyls are lower when using DMF compared to gasoline and even less so than ethanol, which heavily emits acetaldehyde and formaldehyde. The dual-injection mode further reduces the total carbonyl emissions when using DMF and ethanol blends compared to direct-injection (DI).
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Crawford, Morgan H. "Feasibility and Emissions of Compression Ignition Engines Fueled with Waste Vegetable Oil". [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000193.
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Kevric, Arman. "Combustion characteristics of a compression ignition engine running on biodiesel and gasoline blended fuels". Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605993.
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An experimental investigation of the effects of fuel composition on the ignition delay and heat release characteristics of a light duty, automotive compression ignition engine has been carried out. The ignition delay is defined as the period between the start of the main fuel injection event and the start of combustion (SOC). The research has covered a range of fuel types and blends to maximise the effects of composition on the ignition delay and heat release. The fuels used were diesel, gasoline and FAME (Fatty Acid Methyl Esters) produced from rapeseed oil, coconut oil and waste cooking oil. All the engine test studies were carried out using a 2.4 litre displacement, direct injection Ford Puma engine, at test conditions representing low load, mid load and high load at 2000rpm, with EGR rates of up to 35%. Single equation, semi-empirical ignition delay models based upon the Arrhenius equation were studied and developed to fit the experimental ignition delay data, and thus incorporate fuel composition effects. Fuel composition is shown to affect the duration of the ignition delay, but after the start of combustion the heat release characteristics, for a given energy supplied in fuel, proved to be relatively insensitive to fuel composition effects. The premixed fraction is shown to be directly proportional to the ignition delay. The ignition delay of biodiesel fuel is up to 15% shorter than diesel while a gasoline blend of 50% gasoline/50% diesel lengthens the ignition delay by up to 30% with respect to diesel. These differences in the ignition delay affect the engine thermal efficiency by up to 2% due to combustion phasing effects. Gasoline fuel blended up to 80% (by volume) with diesel was combusted successfully, resembling PCCI (Premixed Charged Compression Ignition) combustion regimes, while biodiesel fuel types RME (Rapeseed Methyl Esters), CME (Coconut Methyl Esters) and WCO (Waste Cooking Oil Methyl Esters) all showed differences in heat release characteristics due to ignition delay differences. Calibration changes are necessary to compensate for the fuel composition effects on the ignition delay and subsequent combustion characteristics. An engine specific, single equation ignition delay model was developed that successfully described the experimental ignition delay data over the fuel range of fuel composition: rID = 4.32p-l.02/'P-O.2exp (:;) where EA = A.Kevric University of Nottingham , ' )t8186 . Based upon the analysis of combustion characteristics of the experimental CN+ZS) data, the initial form of a universal ignition delay model was developed, composing of a physical delay portion and a chemical delay portion. A.
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Norouzi, Shahrouz. "Interaction of diesel type fuels and engine fuel system components in compression ignition engines". Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5369/.
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Contact of fuels with engine components at low and elevated temperatures for various amounts of time is found to be challenging as this contact has several effects on engine fuel system components and fuels. Also, storage of fuels for a long period of time is found to have almost the same effect on both engine components and fuels upon engine use. In this thesis fuel and engine components’ contact have been studied for four typical metals used in the construction of many engine fuel systems; in form of pure or alloys (copper, aluminium, mild carbon steel and stainless steel), studied after contact with three of the currently available fuels for use in compression ignition engines. Ultra-low sulphur diesel fuel (ULSD) was used as the fossil fuel, rapeseed methyl ester (RME) as the first generation biofuel and finally gas-to-liquid (GTL) as the second generation of biofuel, obtained via the Fischer-Tropsch process. The investigation was performed in different sections: fuels and metals have been studied for any degradation after contact at low and high temperatures for short and long exposure times, and an understanding of the corrosion process and any degradation on both metals and fuels has been achieved; due to the high hygroscopic character of these fuels and the presence of possible impurities in the fuel, the investigation was extended for analysis of the effect of the presence or absence of absorbed water and dissolved air (in the form of Oxygen) in fuels on degradation and corrosion characteristics of these fuels.
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Groenewegen, Jon-Russell Jacob. "The Performance and Emissions Characteristics of Heavy Fuels in a Small, Spark Ignition Engine". University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1323369703.
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Silva, Isaac Alexander. "Onboard Hydrogen Generation for a Spark Ignition Engine via Thermochemical Recuperation". Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1585124.
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A method of exhaust heat recovery from a spark-ignition internal combustion engine was explored, utilizing a steam reforming thermochemical reactor to produce a hydrogen-rich effluent, which was then consumed in the engine. The effects of hydrogen in the combustion process have been studied extensively, and it has been shown that an extension of the lean stability limit is possible through hydrogen enrichment. The system efficiency and the extension of the operational range of an internal combustion engine were explored through the use of a methane fueled naturally aspirated single cylinder engine co-fueled with syngas produced with an on board methane steam reformer. It was demonstrated that an extension of the lean stability limit is possible using this system.
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Whitelaw, David Stuart. "Droplet atomisation of Newtonian and non-Newtonian fluids including automotive fuels". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266620.
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Verma, Saket. "Experimental investigation and exergy analysis of a dual fuel engine using alternative fuels". Thesis, IITD, 2019. http://eprint.iitd.ac.in:80//handle/2074/8099.
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Liu, Quan. "Planar laser induced fluorescence imaging and analysis with ethanol blended fuels in a direct injection spark ignition engine". Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/14786.
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The currently reported thesis was concerned with visualisation of the charge homogeneity and cyclic variations within the planar fuel field near the spark plug in an optical spark ignition engine fitted with an outwardly opening central direct fuel injector. Specifically, the project examined the effects of fuel type and injection settings, with the overall view to understanding some of the key mechanisms previously identified as leading to particulate formation in such engines. The three fuels studied included a baseline iso-octane, which was directly compared to two gasoline fuels containing 10% (E10) and 85% (E85) volume of ethanol respectively. The engine was a bespoke single cylinder with Bowditch style optical access through a flat piston crown. Charge stratification was studied over a wide spectrum of injection timings using the Planar Laser Induced Fluorescence (PLIF) technique, with additional variation in charge temperature due to injection also estimated when viable using a two-line PLIF approach. Overall, both gasoline-ethanol fuels generally exhibited a higher degree of stratification, albeit at least partly alleviated with elevated rail pressures. Under both warm and cold liner conditions the E10 fuel showed clear evidence of fuel droplets persisting up until ignition. Interestingly, with late injection timing the repeatability of the injection was superior (statistically) with higher ethanol content in the fuel, which may have been associated with the higher charge temperatures aiding control of the evaporation of the main mass of alcohol. The findings were corroborated by undertaking a comprehensive study of the influence of varying fuel type and injection settings on thermodynamic performance and engine-out emissions during firing operation, with additional gas exchange effects also influencing the optimum fuel injection timings.
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Udell, Thomas Gregory. "Reducing emissions of older vehicles through fuel system conversion to natural gas". Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/19896.
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Moxey, Benjamin. "A study of flame development with isooctane alcohol blended fuels in an optical spark ignition engine". Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9866.
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The work was concerned with experimental study of the turbulent flame development process of alcohol fuels, namely ethanol and butanol, in an optically accessed spark ignition research engine. The fuels were evaluated in a single cylinder engine equipped with full-bore overhead optical access operated at typical stoichiometric part-load conditions with images captured using high-speed natural light imaging techniques (or chemiluminescence). The differences in flame development between the fuels was analysed to understand better the impact of high and low alcohol content fuels on combustion. Advanced image analysis, in conjunction with Ricardo WAVE simulation, allowed for the conclusion that the faster burning exhibited by ethanol was the result of the marginally higher laminar burning velocity providing a faster laminar burn phase and accelerating the flame into the turbulent spectrum thus reducing bulk flame distortion and better in-cylinder pressure development. Such physical reactions are often over-looked in the face of chemical differences between fuels. A further study into the variation of maximum in-cylinder pressure values was conducted focussing on iso-octane and ethanol. This study identified two phenomena, namely “saw-toothing” and “creep” in which cluster of cycles feed into one another. From this it became clear that the presence of high pressure during the exhaust process had a large influence on the following cycles. This is another often overlooked phenomenon of direct cycle-to-cycle variation whereby incylinder pressures during blowdown can dictate the duration, load or stability output of the following cycle. Finally the work investigated the impact on flame development of alcohol fuels when the overlap duration was altered. While the engine produced counterintuitive figures of residual gas, ethanol was confirmed as having greater synergy with EGR by displaying less impacted combustion durations c.f. iso-octane. Care should be taken however when analysing these results due to the unique valve configuration of the engine.
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Carr, M. Aaron. "The Comparison of Hydrotreated Vegetable Oils With respect to Petroleum Derived Fuels and the Effects of Transient Plasma Ignition in a Compression-Ignition Engine". Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17333.
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Approved for public release; distribution is unlimitedThis thesis presents the results of an experimental study of the combustion characteristics of algae and camelina derived biofuels as well as the effects of Transient Plasma Ignition in a Compression-Ignition Engine. Testing was conducted for Hydrotreated Renewable Diesel, algae, and benchmarked against F-76 and Diesel #2 fuels as well as Hydrotreated Renewable Jet, camelina, benchmarked against JP-5 across a matrix of constant engine speeds and engine loads in a Detroit Diesel 3-53 legacy engine. A heat release rate analysis and a cycle analysis were performed at each matrix point. The algae and camelina fuels averaged 1.4 Crank Angle Degrees earlier ignition, 2 Crank Angle Degrees longer burn duration, 2.25 atmospheres decrease in Peak Pressure, 1.4 Crank Angle Degrees delay in Angle of Peak Pressure, 0.5 per cent increase in Indicated Mean Effective Pressure, and 6 per cent decrease in Break Specific Fuel Consumption than their petroleum counterpart. A comparison between Diesel #2 at idle was performed between Transient Plasma Ignition Assisted Compression-Ignition and conventional Compression-Ignition. Transient Plasma Ignition averaged a Crank Angle Degree earlier start of combustion, faster pressure rise, but lower Peak Pressures than Compression-Ignition. However, due to failure of the plasma electrode it was not ascertained if this phenomenon is repeatable.
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Stousland, Tyler Brian. "Experimental Use of Hydrogen to Reduce the Consumption of Carbon Fuels in a Compression Ignition Engine and Its Effect on Performance". Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/27641.
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As part of an effort to find use for electric energy produced by wind turbines, Basin Electric started a program to produce hydrogen through electrolysis. It is not enough to simply produce hydrogen, there needs to be uses for the hydrogen in order to make the project worth pursuing.
Hydrogen can be used to supplement diesel fuel in the combustion process in a compression ignition engine. This research will go over two engines which were tested running different combinations of hydrogen and diesel fuel. The results will show how both engines were able to replace up to 50% of the diesel fuel energy input with hydrogen. This paper will also talk about how the addition of hydrogen affects the combustion process by increasing the peak cylinder pressure by 44% and advancing the peak cylinder pressure by 13? of crank angle.
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Li, Guoxing. "Investigation into the dynamic responses and tribological characteristics of cylinder liners in a IC engine with alternative fuels". Thesis, University of Huddersfield, 2016. http://eprints.hud.ac.uk/id/eprint/30287/.
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Promoted by the realisation of dwindling fossil fuel supplies and their adverse environmental impacts, there more and more types of alternative fuels to fossil diesel have been used and investigated in compression ignition engines. However, the majority of researches on alternative fuels mainly focus on their power performance, efficiency and emission performance, without fully investigating the potential effects on the vibro-acoustic emissions and tribological characteristics of engines caused by their significant differences in physical and chemical properties. Consequently, the impacts of long-term use of alternative fuels on structural failure, lubrication degradation, friction aggravation, overall service life spans and associated maintenance activities of internal combustion (IC) engines have not yet been fully understood. To reduce this gap this thesis focuses on the investigation into the vibration responses of cylinder liners in a diesel engine to accurately characterises the tribological behaviour between the piston rings and cylinders which is one of the most decisive sub-processes that determine engine performance and yet is correlated with the combustion of different fuels. In particular, the investigation was carried out by coupling the hydrodynamic lubrication model with structural vibration effects through a series of extensive numerical simulations and systematic experimental evaluations in order to establish a vibration based technique to monitoring tribological behaviour and thereby accurately assess the influence. Based on the dynamic coupling mechanisms between the combustion characteristics of alternative fuels and the tribological behaviours of cylinder liners, the most significant influences from the fuel burning on tribological behaviour of cylinder liners concerned in this study is a direct and physical approach such as the effect of liner vibrations on cylinder friction process, even though an indirect and chemical but very slow approach such as the deterioration of oil properties by combustion products can happen. To characterise the direct influence a finite element dynamic model was developed and validated for predicting the dynamic responses of cylinder liners to respective excitation sources including the highly nonlinear combustion pressure shocks and subsequent piston slap impacts. The realistic consideration of both the characteristics of structural modes up to 15kHz and nonlinearities of elastic assembly constraints allows obtaining accurate prediction that the combustion shocks cause vibrations in a frequency range around 10kHz with an amplitude order of 0.01μm, whereas the piston slaps in frequency range from 1k to 5kHz with an amplitude order 0.2μm, which gives a clear and quantitative indication of the nonlinear phenomena of liner vibration due to combusting alternative fuels and varying lubrication conditions. In addition, a decomposition analysis of piston side-thrust forces provides more insight of the localized response characteristics corresponding to coupling interactions of combustion force with inertia force of piston assembly. To further investigate the potential influences of structural deformations to tribological behaviours of cylinder assemblies, a new dynamic deformation based lubrication model was developed based on an employment of improved shearing factors in which the effect of inevitable liner vibrations is included to obtain a more realistic lubricating film formation, distribution and tribological behaviours. The simulation studies show that this advancement in modelling oil films predicts that the biodiesel with more intense vibration emissions is able to reduce the friction loss between pistons and liners, whereas the methanol-diesel blend with weakened liner dynamic response may exacerbate the friction loss of IC engines. This finding confirms further that the vibration responses allow a straightforward and in-depth indication of the effect generated by using different fuels. In addition, a further experimental investigation was carried out based on a motoring engine test, in which high frequency sinusoidal vibrations at 25 kHz, 30 kHz and 40 kHz are added to the external surface of the linear. The observable changes in motoring torque verify that proper external vibrations can affect the tribological behaviours between the pistons and liners, including both asperity friction and viscous friction, and resulting in the friction reduction of IC engines. Particularly the 40 kHz vibration at the maximal driving power of the test device can achieve a reduction of 1.79% in the motoring torque. This has demonstrated more on the effectiveness of this vibration based diagnostic method in assessing the influences of alternative fuels upon tribological behaviours of piston ring and cylinder liners. Finally, further researches on the subjects is also proposed in order to complete the vibration based diagnostics in achieving more accurate assessment of engine lubrication conditions and effective friction reduction.
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Sinuka, Yonwaba. "Performance testing of a diesel engine running on varying blends of jatropha oil, waste cooking oil and diesel fuel". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2436.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016.The high cost of fossil fuels and the fact that the world has arguably reached its peak oil production, has driven the need to seek alternative fuel sources. The main objective of the current study is to determine the performance of a laboratory-mounted diesel engine when fuelled with varying laboratory prepared biofuel and biodiesel and whether the advancement of the injection timing parameters will improve the engine power output and improve the smoke effect of these different fuel blends. The laboratory prepared biofuels used in this project range from 100% bio-fuel (BF100) to 50%, 30% and 10% biodiesel blends (BF50, BF30 and BF10, respectively). It should be noted that these blends are not commercially available, since they were blended in the laboratory specifically for these tests. The overall results of the study show that there is a distinct opportunity for using certain bio-fuel blends in specific applications as the power outputs are no more than one quarter less than that of base diesel. Concomitantly, the smoke opacity in all of the blends is lower than that of base diesel, which is a significant benefit in terms of their overall air emissions.
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Kapadia, Bhavin Kanaiyalal. "Development Of A Single Cylinder SI Engine For 100% Biogas Operation". Thesis, Indian Institute of Science, 2006. https://etd.iisc.ac.in/handle/2005/283.
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This work concerns a systematic study of IC engine operation with 100% biogas as fuel (as opposed to the dual-fuel mode) with particular emphasis on operational issues and the quest for high efficiency strategies. As a first step, a commercially available 1.2 kW genset engine is modified for biogas operation. The conventional premixing of air and biogas is compared with a new manifold injection strategy. The effect of biogas composition on engine performance is also studied.
Results from the genset engine study indicate a very low overall efficiency of the system. This is mainly due to the very low compression ratio (4.5) of the engine. To gain further insight into factors that contribute to this low efficiency, thermodynamic engine simulations are conducted. Reasonable agreement with experiments is obtained after incorporating estimated combustion durations. Subsequently, the model is used as a tool to predict effect of different parameters such as compression ratio, spark timing and combustion durations on engine performance and efficiency. Simulations show that significant improvement in performance can be obtained at high compression ratios.
As a step towards developing a more efficient system and based on insight obtained from simulations, a high compression ratio (9.2) engine is selected. This engine is coupled to a 3 kW alternator and operated on 100% biogas. Both strategies, i.e., premixing and manifold injection are implemented. The results show very high overall (chemical to electrical) efficiencies with a maximum value of 22% at 1.4 kW with the manifold injection strategy. The new manifold injection strategy proposed here is found to be clearly superior to the conventional premixing method. The main reasons are the higher volumetric efficiency (25% higher than that for the premixing mode of supply) and overall lean operation of the engine across the entire load range. Predictions show excellent agreement with measurements, enabling the model to be used as a tool for further study. Simulations suggest that a higher compression ratio (up to 13) and appropriate spark advance can lead to higher engine power output and efficiency.
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Kapadia, Bhavin Kanaiyalal. "Development Of A Single Cylinder SI Engine For 100% Biogas Operation". Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/283.
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This work concerns a systematic study of IC engine operation with 100% biogas as fuel (as opposed to the dual-fuel mode) with particular emphasis on operational issues and the quest for high efficiency strategies. As a first step, a commercially available 1.2 kW genset engine is modified for biogas operation. The conventional premixing of air and biogas is compared with a new manifold injection strategy. The effect of biogas composition on engine performance is also studied.
Results from the genset engine study indicate a very low overall efficiency of the system. This is mainly due to the very low compression ratio (4.5) of the engine. To gain further insight into factors that contribute to this low efficiency, thermodynamic engine simulations are conducted. Reasonable agreement with experiments is obtained after incorporating estimated combustion durations. Subsequently, the model is used as a tool to predict effect of different parameters such as compression ratio, spark timing and combustion durations on engine performance and efficiency. Simulations show that significant improvement in performance can be obtained at high compression ratios.
As a step towards developing a more efficient system and based on insight obtained from simulations, a high compression ratio (9.2) engine is selected. This engine is coupled to a 3 kW alternator and operated on 100% biogas. Both strategies, i.e., premixing and manifold injection are implemented. The results show very high overall (chemical to electrical) efficiencies with a maximum value of 22% at 1.4 kW with the manifold injection strategy. The new manifold injection strategy proposed here is found to be clearly superior to the conventional premixing method. The main reasons are the higher volumetric efficiency (25% higher than that for the premixing mode of supply) and overall lean operation of the engine across the entire load range. Predictions show excellent agreement with measurements, enabling the model to be used as a tool for further study. Simulations suggest that a higher compression ratio (up to 13) and appropriate spark advance can lead to higher engine power output and efficiency.
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Everett, Ryan Vincent. "An Improved Model-Based Methodology for Calibration of an Alternative Fueled Engine". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1321285633.
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Vittori, Ruggero Maria. "Experimental study on the effect of stoichiometric air/fuel ratio of three binary oxygenated fuel blends on combustion and emissions of a heavy duty Diesel engine". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18203/.
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Low Temperature Combustion (LTC) is believed to be the best solution to the Diesel NOx and soot emissions trade-off: the latest development in LTC methods is PPC (Partially Premixed Combustion) which can be considered as a combination of Homogeneous Charge Compression Ignition (HCCI) and conventional Diesel combustion.
The increasing interest in high-octane alternative fuels, such as alcohols and aromatic compounds, leads to investigate their combustion behaviour, in order to develop cleaner fuels, making another small step towards new cleaner engines.
In this thesis, three binary oxygenated fuel blends are selected, with the aim of studying how their molecular structures and stoichiometric air-fuel ratio influenced the combustion performances and emissions of a truck heavy-duty Diesel engine.
The first part describes the fundamental elements of LTC and gives a background on the typical Diesel combustion emissions, with the description of the alternative test fuels of this research.
The second part is about the engine setup, with particular attention towards the emission measurement and data acquisition systems.
The third part gives a background on the important parameters of this research, mostly combustion control parameters: it is fundamental to understand the test results, which are presented in the final part of the thesis.
This master thesis project has been developed in collaboration with the “Multiphase and reactive flows” research group at TU/e, Eindhoven University of Technology, in the Netherlands.
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Ghomashi, Hossein. "Modelling the combustion in a dual fuel HCCI engine : investigation of knock, compression ratio, equivalence ratio and timing in a Homogeneous Charge Compression Ignition (HCCI) engine with natural gas and diesel fuels using modelling and simulation". Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7344.
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This thesis is about modelling of the combustion and emissions of dual fuel HCCI engines for design of “engine combustion system”. For modelling the combustion first the laminar flamelet model and a hybrid Lagrangian / Eulerian method are developed and implemented to provide a framework for incorporating detailed chemical kinetics. This model can be applied to an engine for the validation of the chemical kinetic mechanism. The chemical kinetics, reaction rates and their equations lead to a certain formula for which the coefficients can be obtained from different sources, such as NASA polynomials [1]. This is followed by study of the simulation results and significant findings. Finally, for investigation of the knock phenomenon some characteristics such as compression ratio, fuel equivalence ratio, spark timing and their effects on the performance of an engine are examined and discussed. The OH radical concentration (which is the main factor for production of knock) is evaluated with regard to adjustment of the above mentioned characteristic parameters. In the second part of this work the specification of the sample engine is given and the results obtained from simulation are compared with experimental results for this sample engine, in order to validate the method applied in AVL Fire software. This method is used to investigate and optimize the effects of parameters such as inlet temperature, fuels ratio, diesel fuel injection timing, engine RPM and EGR on combustion in a dual fuel HCCI engine. For modelling the dual fuel HCCI engine AVL FIRE software is applied to simulate the combustion and study the optimization of a combustion chamber design. The findings for the dual fuel HCCI engine show that the mixture of methane and diesel fuel has a great influence on an engine's power and emissions. Inlet air temperature has also a significant role in the start of combustion so that inlet temperature is a factor in auto-ignition. With an increase of methane fuel, the burning process will be more rapid and oxidation becomes more complete. As a result, the amounts of CO and HC emissions decrease remarkably. With an increase of premixed ratio beyond a certain amount, NOX emissions decrease. With pressure increases markedly and at high RPM, knock phenomenon is observed in HCCI combustion.
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Ibrahim, Umar. "Characterization of Biodiesel Blends Effects on Aftertreatment Systems and Aftertreatment-based Blend Level Estimation". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1451906418.
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Balagurunathan, Jayakishan. "Investigation of Ignition Delay Times of Conventional (JP-8) and Synthetic (S-8) Jet Fuels: A Shock Tube Study". University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1330351552.
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Zinner, Christopher. "METHANE AND DIMETHYL ETHER OXIDATION AT ELEVATED TEMPERATURES AND PRESSURE". Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3457.
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Autoignition and oxidation of two Methane (CH4) and Dimethyl Ether (CH3OCH3 or DME) mixtures in air were studied in shock tubes over a wide range of equivalence ratios at elevated temperatures and pressures. These experiments were conducted in the reflected shock region with pressures ranging from 0.8 to 35.7 atmospheres, temperatures ranging from 913 to 1650 K, and equivalence ratios of 2.0, 1.0, 0.5, and 0.3. Ignition delay times were obtained from shock-tube endwall pressure traces for fuel mixtures of CH4/CH3OCH3 in ratios of 80/20 percent volume and 60/40 percent volume, respectively. Close examination of the data revealed that energy release from the mixture is occurring in the time between the arrival of the incident shock wave and the ignition event. An adjustment scheme for temperature and pressure was devised to account for this energy release and its effect on the ignition of the mixture. Two separate ignition delay correlations were developed for these pressure- and temperature-adjusted data. These correlations estimate ignition delay from known temperature, pressure, and species mole fractions of methane, dimethyl ether, and air (0.21 O2 + 0.79 N2). The first correlation was developed for ignition delay occurring at temperatures greater than or equal to 1175 K and pressures ranging from 0.8 to 35.3 atm. The second correlation was developed for ignition delay occurring at temperatures less than or equal to 1175 K and pressures ranging from 18.5 to 40.0 atm. Overall good agreement was found to exist between the two correlations and the data of these experiments. Findings of these experiments also include that with pressures at or below ten atm, increased concentrations of dimethyl ether will consistently produce faster ignition times. At pressures greater than ten atmospheres it is possible for fuel rich mixtures with lower concentrations of dimethyl ether to give the fastest ignition times. This work represents the most thorough shock tube investigation for oxidation of methane with high concentration levels of dimethyl ether at gas turbine engine relevant temperatures and pressures. The findings of this study should serve as a validation for detailed chemical kinetics mechanisms.M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering MSME
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MANELLI, ANDREA. "Engine Technologies for Reduction of Fuel Consumption and Pollutant Emissions in Light-Duty Diesel Engines". Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2971996.
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Šmerda, Ondřej. "Návrh koncepce leteckého motoru na CNG". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401574.
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Master’s thesis deals with comparsion and rating the compressed natural gas as an aircraft piston engine fuel. An information search of conventional fuels and differences of the fuel systems for AVGAS and CNG is included. Next part describes the aircraft and its engine on which is the mathematic model based. After that perfomance and consumption data are calculated for both fuels and the results are then compared. At the end of the thesis, a design of the CNG fuel system with components selection is described.
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Nevot, Cercós Javier. "Diseño de un controlador avanzado basado en redes neuronales para la gestión de la mezcla aire-gasolina en un motor alternativo". Doctoral thesis, Universitat Politècnica de Catalunya, 2000. http://hdl.handle.net/10803/5933.
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En la presente tesis se desarrolla un sistema de control de la mezcla de aire y gasolina en un motor alternativo de cuatro tiempos, basado en redes neuronales. Para que el catalizador logre un grado de depuración aceptable con todos los gases contaminantes simultáneamente, debe mantenerse la proporción de aire y combustible, dentro de una banda muy estrecha. En estado estacionario, este objetivo se cumple sin demasiados problemas, pero el funcionamiento habitual de un vehículo es en régimen muy transitorio, donde los sistemas convencionales no logran evitar desviaciones importantes del punto de consigna. Estos se basan además en una gran cantidad de tablas estáticas, que deben calibrarse de forma experimental, lo cual es bastante costoso tanto en tiempo como en dinero.Para evitar estos problemas se ha diseñado un modelo matemático de un motor, que comprende todo el proceso de formación de la mezcla, sensores, la generación del par motor y la dinámica del vehículo. La realización final se ha realizado en el lenguaje de simulación MatLab/Simulink®. Los datos requeridos son fácilmente obtenibles bien por metrología, bien de forma experimental. Se ha validado con un motor SEAT de 1,6 l y 74 kW.
Como primer paso se ha aplicado una estrategia de control convencional bastante simple, consistente en un controlador feedforward estático, más un controlador feedback de tipo PI ó PID. Esto ha permitido el estudio de las principales características del motor desde el punto de vista de control.
Con los resultados obtenidos se ha diseñado un observador basado en una red neuronal, que elimine los retardos puros del sistema y que pueda ser utilizado para cerrar el lazo de control. Primero se ha usado una red feedforward, pero vistos los malos resultados, se ha desarrollado una red neuronal recurrente a partir de la red de Elman, que se ha modificado convenientemente para adaptarla a las dificultades propias del problema. El algoritmo de entrenamiento utilizado se basa en el de retropropagación clásico, y modifica no sólo los pesos entre capas, sino también los correspondientes a las neuronas de contexto, las cuales permiten memorizar estados internos. La principal mejora consiste en separar las neuronas de contexto en tantos grupos como entradas tiene la red, y entrenarlos por separado, de modo que cada grupo se adapte a la dinámica particular de la entrada a la que va asociado. Se muestra mediante simulación el comportamiento del conjunto motor más observador en lazo cerrado, y se compara con el esquema convencional. Se prueba asimismo la robustez del sistema frente a distintas consignas, ruido en la planta y defectos de sintonía.
In the present thesis a control system for the air-fuel mixture in a reciprocating four-stroke engine is developed, based on neural networks. The air-fuel ratio has to be kept within a very narrow window so that the catalyst achieves an acceptable degree of purification simultaneously with all the polluting gases. In steady state, this goal can be fulfilled without difficulties, but the usual operation of a vehicle is in a very transient state, where the conventional systems are not able to avoid important excursions from the set point. They also rely on a great number of look-up tables, which have to be tuned experimentally, thus with an enormous investment of money and time.
To avoid those problems a mathematical model of an engine has been designed, in such a way that it comprises of the whole mixture formation process, sensors, the torque generation and the vehicle dynamics. Finally it has been implemented in the simulation language MatLab/Simulink®. The required data is easily available both from metrology, and experimental work. It has been validated with a 1,6 litre 74 kW SEAT engine.
As a first step, a quite simple conventional control strategy has been applied, consisting of a static feedforward controller, and a PI or PID feedback controller. This has permitted studying the main features of the engine from the control point of view.
With the obtained results an observer based on a neural network has been designed, which eliminates the delays of the system and that can be used to close the control loop. First a feedforward network has been used, but due to the bad results, a recurrent neural network has been developed starting from the Elman network, which has been properly modified in order to adapt it to the characteristic difficulties of the problem. The training algorithm used is based on that of classical backpropagation, and it modifies not only the weights interconnecting different layers, but also those corresponding to the context neurons, which allow the memorising of internal states. The main improvement consists in separating the context neurons in as many groups as the network has inputs, and to train them separately, so that each group adapts to the particular dynamics of the input with which it is associated. The behaviour of the engine plus the observer in closed loop is shown by means of simulation, and is compared with the conventional scheme. It is proven the robustness of system response to different set points, noise in the plant and tuning defects.
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Vinay, Kumar Nerella V. "An Analysis on Vehicular Exhaust Emissions from Transit Buses Running on Biodiesel Blends". University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271886446.
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Garimella, Venkata Naga Ravikanth. "Exhaust Emissions Analysis for Ultra Low Sulfur Diesel and Biodiesel Garbage Trucks". University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1290203383.
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Fagundez, Jean Lucca Souza. "Avaliação energética do uso de álcoois combustíveis em motores de combustão interna". Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/10624.
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The present work studies the use of a two-zone computer model to simulate the operation of an internal combustion engine with spark ignition fueled with alcohol fuels and gasohol. To fit the model to the experimental data, a parameter estimation technique was used and the heat transfer correlation that could better fit the tested fuels and engine was determined. The tested fuels were: hydrous ethanol, wet ethanol (from 10% to 40% of water, by volume), n-butanol, n-butanol/ethanol blend and gasohol. In addition to the experimental tests with the engine, tests with a packed distillation column under batch process were made in order to determine the energy efficiency involved between production and use as a fuel for hydrous ethanol and wet ethanol fuels. The results showed that the two-zone model was able to predict satisfactorily the behavior of all tested fuels, accurately obtaining the engine performance parameters. In terms of energy efficiency, wet ethanol fuels have advantage over hydrous ethanol fuel, especially in the case of 30% of water by volume, where energy efficiency reaches its maximum value, considering the distillation and engine combustion processes. The n-butanol fuel was capable of act as a surrogate for both hydrous ethanol and gasohol with efficiency, leading the engine to have good performance in the tested operational conditions and appearing, due to this, as an interesting alternative of renewable fuel to be inserted in the Brazilian energy matrix.O presente trabalho investiga o uso de um modelo computacional de duas zonas para simular o funcionamento de um motor de combustão interna com ignição por centelha abastecido com álcoois combustíveis e gasolina. Para o ajuste do modelo fez-se uso de técnica de estimação de parâmetros e determinação da correlação de transferência de calor capaz de melhor se ajustar aos combustíveis e ao motor testados. Os combustíveis utilizados foram: etanol hidratado, etanol super-hidratado (de 10% a 40% de água, em volume), n-butanol, misturas de n-butanol e etanol e gasolina e etanol. Além dos testes experimentais com motor, testes de bancada com uma coluna de destilação recheada em regime descontínuo foram realizados a fim de determinar a eficiência energética do processo de produção e queima de etanol hidratado e super-hidratado. Os resultados obtidos mostraram que o modelo de duas zonas é capaz de prever de maneira satisfatória o comportamento de todos os combustíveis testados, com determinação precisa de parâmetros de desempenho do motor. Em termos de eficiência energética, o etanol super-hidratado tem vantagem em relação ao etanol hidratado combustível, em especial quando com 30% de água em volume, onde a eficiência energética é máxima, considerados os processos de destilação e queima no motor. O n-butanol combustível usado mostrou-se capaz de substituir eficientemente tanto o etanol hidratado como a gasolina brasileira, levando o motor a ter boa performance nas condições operacionais testadas e aparecendo, dessa forma, como interessante alternativa de combustível renovável a ser inserida na matriz energética brasileira.
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Kumar, Ashok. "Study on ghg emissions in an automotive compression ignition engine using alternative fuels". Thesis, 2018. http://localhost:8080/xmlui/handle/12345678/7692.
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Toulson, E. "Applying alternative fuels in place of hydrogen to the jet ignition process". 2008. http://repository.unimelb.edu.au/10187/3532.
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Hydrogen Assisted Jet Ignition (HAJI) is an advanced ignition process that allows ignition of ultra-lean mixtures in an otherwise standard gasoline fuelled spark ignition engine. Under typical operating conditions, a small amount of H2 (~ 2 % ofthe main fuel energy or roughly the equivalent of 1 g/km of H2) is injected just before ignition in the region of the spark plug. By locating the spark plug in a small prechamber (less than 1 % of the clearance volume) and by employing a H2 rich mixture, the content of the prechamber is plentiful in the active species that form radicals H and OH on decomposition and has a relatively high energy level compared to the lean main chamber contents. Thus, the vigorous jets of chemically active combustion products that issue through orifices, which connect to the main chamber, burn the main charge rapidly and with almost no combustion variability (less than 2% coefficient of variation in IMEP even at λ = 2.5).The benefits from the low temperature combustion at λ = 2 and leaner are that almost zero NOx is formed and there is an improvement in thermal efficiency. Efficiency improvements are a result of the elimination of dissociation, such as CO2 to CO, which normally occurs at high temperatures, together with reduced throttling losses to maintain the same road power. It is even possible to run the engine in an entirely unthrottled mode, but at λ = 5.
Although only a small amount of H2 is required for the HAJI process, it is difficult to both refuel H2 and store it onboard. In order to overcome these obstacles, the viability of a variety of more convenient fuels was experimentally assessed based on criteria such as combustion stability, lean limit and emission levels. The prechamber fuels tested were liquefied petroleum gas (LPG), natural gas, reformed gasoline and carbon monoxide. Additionally, LPG was employed as the main fuel in conjunction with H2 or LPG in the prechamber. Furthermore, the effects of HAJI operation under sufficient exhaust gas recirculation to allow stoichiometric fuel-air supply, thus permitting three-way catalyst application were also examined.
In addition to experiments, prechamber and main chamber flame propagation modeling was completed to examine the effects of each prechamber fuel on the ignition of the main fuel, which consisted of either LPG or gasoline. The modeling and experimental results offered similar trends, with the modeling results giving insight into the physiochemical process by which main fuel combustion is initiated in the HAJI process.
Both the modeling and experimental results indicate that the level of ignition enhancement provided by HAJI is highly dependent on the generation of chemical species and not solely on the energy content of the prechamber fuel. Although H2 was found to be the most effective fuel, in a study of a very light load condition (70 kPa MAP) especially when running in the ultra-lean region, the alternative fuels were effective at running between λ = 2-2.5 with almost zero NOx formation. These lean limits are about twice the value possible with spark ignition (λ = 1.25) in this engine at similar load conditions. In addition, the LPG results are very encouraging as they offer the possibility of a HAJI like system where a commercially available fuel is used as both the main and prechamber fuel, while providing thermal efficiency improvements over stoichiometric operation and meeting current NOx emission standards.
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Burke, PH. "Performance appraisal of a four-stroke hydrogen internal combustion engine". Thesis, 2005. https://eprints.utas.edu.au/19195/1/whole_BurkePatrickHugh2005_thesis.pdf.
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Fossil fuel depletion and environmental factors had lead the search for alternative transportation fuels. One such alternative is hydrogen. Of the potential transportation fuels of the future hydrogen is the only one which is both sustainable and environmentally friendly.
A good understanding of the quantitative and qualitative trends are available in the literature, for petrol driven vehicles, as established knowledge. However, understanding of the near zero emissions and associated conversion technology, using hydrogen as fuel, has been in the domain of few automotive applications around the world.
This work is aimed at converting a commercially available vehicle to operate on hydrogen as a design and manufacturing exercise to showcase the use of alternative fuel. The chosen vehicle is the Honda CT110 motor bike or better known as the Australia Post `postie bike'.
In this thesis, a rigorous design process for conversion to hydrogen is proposed and implemented from first principles. The test rig development associated with the calculations for fuel flow rates and associated engine management systems are an integral part of this overall systematic design. As part of the investigation an innovative fuel injection system together with fuel-air-intake system is designed and incorporated. Traditional problems with pre-ignition in hydrogen engines are found to be minimized by developed systematic design techniques.
As part of this investigation a comprehensive range of engine operating conditions are investigated using both petrol and hydrogen as fuel. The comparisons have shown that for the same operating conditions, hydrogen powered vehicles suffer losses in power and thermal efficiency. With the performance requirements of the vehicle in mind the reductions in performance are not seen as a major compromise. Exhaust emission performance showed significant reduction in oxides of nitrogen and no significant emissions of hydrocarbons, carbon dioxide and carbon monoxide. Future potential developments suggested by this work is expected to improve performance outputs further.
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Mazumder, Diya Basu 1974. "Essays in vehicle emission policies". Thesis, 2007. http://hdl.handle.net/2152/3154.
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The first chapter of this dissertation examines welfare impacts of a combination of subsidies to alternative fuels (AFs) and alternative fuel vehicles (AFVs), and how they compare to gasoline taxes. The particular AF examined here is ethanol that is produced from agricultural products in a small open economy. The model in this paper characterizes a country or state where gasoline is the major source of fuel for automobiles, but that also produces and consumes ethanol as an AF. Gasoline combustion is polluting and its use equals the total amount of emissions produced. Thus, a gasoline tax here is the same as an emissions tax and is the most direct environmental instrument. However, increasing gasoline taxes for pollution purposes is often politically not feasible. Thus, this paper studies how closely subsidies to alternative fuels (AFs) and alternative fuel vehicles (AFVs) emulate abatement behavior from a unit gasoline tax in a simple three sector general equilibrium model, and in the presence of pre-existing labor taxes. The model can also be used to track the effects of each policy on outputs, exports, and fuel use. The analytical results of the model are then calibrated to data from the largest ethanol producing state in the U.S., namely Illinois. The paper finds that subsidies can achieve up to 64 percent of the welfare gains from the gasoline tax, if the uncompensated wage elasticity is low enough or the elasticities of substitution between the transportation goods is high enough. The second chapter estimates behavior of households who jointly make discrete decisions about vehicle ownership and continuous decisions about miles driven. The paper uses seven years of data from 1995-2001 for the 35 states and union territories of India. The estimated parameters will be used to calculate elasticities of each different type of vehicle for percentage changes in petrol price per unit distance travelled and in vehicle taxes. The paper also computes income and price elasticities for petrol consumption. Two types of vehicles predominant in India are cars and two-wheelers such as motorcycles, mopeds, and scooters. The latter type of vehicle is more fuel efficient than the former. However, patterns of vehicle ownership across the country reflect a growing number of cars relative to motorcycles. This paper investigates the impact alternative policies such as taxes on petrol or on cars have on efficient methods of vehicle emission abatement in India. In particular, the chapter estimates the effect of each such policy on vehicle choice and driving behavior, and how they in turn affect emissions. The main results are summarized as follows: First, continuous choice own-price elasticities are higher for 4w relative to 2w, given age, and for older vehicles relative to newer ones, within each category. Second, discrete choice own-price elasticities with respect to capital cost are higher for 2w relative to 4w. Moreover, older vehicles of each type are more sensitive to higher vehicle prices relative to their newer counterparts. Third, income elasticities for discrete vehicle choices are all positive and greater than unity. Thus, higher income encourages purchase of newer vehicles of each type. Moreover, usage of vehicles rises with income, conditional on the particular vehicle choice. Finally, the paper conducts simulations that alter the price per kilometer by adding either an additional gas tax, a distance tax or an emissions tax. Results show that a distance tax reduces vehicle kilometers traveled the most, followed by an emissions tax and lastly by the gas tax. However, local emissions are reduced the most by an emissions tax, followed by a distance tax and then by a gasoline tax. Even though it would be ideal to compare the results obtained in this paper to results generated using a micro-level data set, the estimates presented here are indicative of whether a distance tax or a gasoline tax is more effective for emissions abatement in India. The third chapter of this dissertation evaluates how information asymmetry in private automobile markets affects programs to accelerate vehicle retirement, also known as scrappage programs. We use a dynamic framework where agents have heterogenous preference for car quality. Cars can either be new, or used. While all new cars have the same quality, used cars can be of high- or low-quality. The quality of a car is perfectly correlated with emissions. The goal of a scrappage program is to induce car owners to voluntarily scrap low-quality used cars. One key result is that in the presence of adverse selection a subsidy that maintains an active resale market unambiguously makes all types of consumers better off. However, if this option of implementing the subsidy does not exist, then the only other way to induce effective scrappage in our framework is to shut down the used car market. Welfare implications suggest that it might be better not to do anything rather than have a scrappage program such as the latter.text
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(11208897), Shubham Pradeep Agnihotri. "EFFICIENCY IMPROVEMENT ANALYSIS FOR COMMERCIAL VEHICLES BY (I) POWERTRAIN HYBRIDIZATION AND (II) CYLINDER DEACTIVATION FOR NATURAL GAS ENGINES". Thesis, 2021.
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The commercial vehicle sector is an important enabler of the economy and is heavily dependent on fossil fuels. In the fight against climate change, reduction of emissions by improving fuel economy is a key step for the commercial vehicle sector. Improving fuel economy deals with reducing energy losses from fuel to the wheels. This study aims to analyze efficiency improvements for two systems that are important in reducing CO2 emissions - hybrid powertrains and natural gas engines. At first, a prototype series hybrid powertrain was analyzed based on on-highway data collected from its powertrain components. Work done per mile by the electrical components of the powertrain showed inefficient battery operation. The net energy delivery of the battery was close to zero at the end of the runs. This indicated battery was majorly used as an energy storage device. Roughly 15% of losses were observed in the power electronics to supply power from battery and generator to the motor. Ability of the hybrid system to capture regenerative energy and utilize it to propel the vehicle is a primary cause for fuel savings. The ability of this system to capture the regenerative energy was studied by modeling the system. The vehicle model demonstrated that the system was capturing most of the theoretically available regenerative energy. The thesis also demonstrates the possibility of reduction of vehicular level losses for the prototype truck. Drag and rolling resistance coefficients were estimated based on two coast down tests conducted. The ratio of captured regenerative to the drive energy energy for estimated drag and rolling resistant coefficients showed that the current system utilizes 4%-9% of its drive energy from the captured regenerative energy. Whereas a low mileage Peterbilt 579 truck could increase the energy capture ratio to 8%-18% for the same drive profile and route. Decrease in the truck’s aerodynamic drag and rolling resistance can potentially improve the fuel benefits.
The second study aimed to reduce the engine level pumping losses for a natural gas spark ignition engine by cylinder deactivation (CDA). Spark ignited stoichiometric engines with an intake throttle valve encounter pumping/throttling losses at low speed, low loads due to the restriction of intake air by the throttle body. A simulation study for CDA on a six cylinder natural gas engine model was performed in GT- Power. The simulations were ran for steady state operating points with a torque range 25-560 ftlbs and 1600 rpm. Two , three and four cylinders were deactivated in the simulation study. CDA showed significant fuel benefits with increase in brake thermal efficiency and reduction in brake specific fuel consumption depending on the number of deactivated cylinders. The fuel benefits tend to decrease with increase in torque. Engine cycle efficiencies were analyzed to investigate the efficiency improvements. The open cycle efficiency is the main contributor to the overall increase in the brake thermal efficiency. The work done by the engine to overcome the gas exchange during the intake and exhaust stroke is referred to the pumping losses. The reduction in pumping losses cause an improvement in the open cycle efficiency. By deactivating cylinders, the engine meets its low torque requirements by increase in the intake manifold pressure. Increased intake manifold pressure also resulted in reduction of the pumping loop indicating reduced pumping losses. A major limitation of the CDA strategy was ability to meet EGR fraction requirements. The increase in intake manifold pressure also caused a reduction in the delta pressure across the EGR valve. At higher torques with high EGR requirements CDA strategy was unable to meet the required EGR fraction targets. This limited the benefits of CDA to a specific torque range based on the number of deactivated cylinders. Some variable valve actuation strategies were suggested to overcome this challenge and extend the benefits of CDA for a greater torque range.