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1
Robinson, Kevin. "IC engine coolant heat transfer studies." Thesis, University of Bath, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275444.
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Knutsson, Magnus. "Modelling of IC-Engine Intake Noise." Doctoral thesis, Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10549.
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Rivara, Nick. "IC Engine Control by Ionization Current Sensing." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510971.
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Duan, Shang You. "Fuel injection control for an IC engine." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335571.
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Gräsberg, Pontus. "IC-Engine Source Characterisation and exhaust system simulations." Thesis, KTH, Marcus Wallenberg Laboratoriet MWL, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299411.
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To be able to predict the sound pressure level emitted by a exhaust system one must be able to describe the source. The source in the form of an engine can linearly be described as a source strength and a source impedance. An IC-engine can acoustically have a non-linear part meaning that the source characteristics have a dependency on the load. The first part of this work investigates through simulation's in GT-Power how these characteristics are affected by the load connected to the source. The Second part of the work combines the source characteristics with simulations of a muffler and compares to different methods of getting the pressure at the outlet of the exhaust. The first method is direct simulation of the muffler in COMSOL Multiphysics and the second is a transfer matrix based calculation. How sensitive the results at the outlet are to changes in the source impedance is also tested. It is concluded that using five loads for the multiload method in the form of five different lengths on the pipe connecting the engine and muffler works when the pipe have the same length as would be seen in reality. Furthermore, the pipe lengths should have a small range, 100 mm between largest and smallest pipe length giving good results. The source characteristics were at least above 1000 RPM stable enough as to not significantly change the sound pressure level at the outlet.<br>För att kunna modellera ljudtrycket som avges från ett avgassystem behöver man kunna beskriva källan. Källan i form av en bränslemotor kan linjärt beskrivas som en källstyrka och en källimpedans. En bränslemotor kan dock ha en akustisk ickelinjär del vilket medför att källan kan vara beroende utav vilken last i form av ljuddämpare den är kopplad till. Första delen av detta arbete undersöker genom motorsimuleringar i GT-Power hur lasten påverkar källkarakteristiken. Den andra delen av arbetet kombinerar källkarakteristiken med simuleringar av ljuddämparen och jämför olika metoder för att få ljudtrycket vid utloppet av avgassystemet. Den första metoden för detta är direkt simulering av ljuddämparen i COMSOL Multiphysics där källkarakteristiken inkluderas och den andra metoden är transfermatris baserad. Det testas också hur känsligt ljudtrycket vid utloppet av ljuddämparen är för variationer i impedansen. För källkarakteristiken används fem laster per uträkning och slutsatsen dras att lasten i form av röret mellan motor och ljuddämpare samt ljuddämparen bör vara så lik som möjligt det riktiga systemet. Utöver det dras slutsatsen att en liten variation i det kopplande rörets längd ger bättre resultat och att en variation mellan största och minsta röret på 100 mm ger bra resultat. Till sist dras slutsatsen att för varvtal över 1000 RPM är källkarakteristiken tillräckligt stabil för att ge stabila resultat vid utloppet av ljuddämparen, medans under 1000 RPM kan det vara stabilt nog men här är validering viktigare.
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Pezouvanis, Antonios. "Engine modelling for virtual mapping : development of a physics based cycle-by-cycle virtual engine that can be used for cyclic engine mapping applications, engine flow modelling, ECU calibration, real-time engine control or vehicle simulation studies." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4419.
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After undergoing a study about current engine modelling and mapping approaches as well as the engine modelling requirements for different applications, a major problem found to be present is the extensive and time consuming mapping procedure that every engine has to go through so that all control parameters can be derived from experimental data. To improve this, a cycle-by-cycle modelling approach has been chosen to mathematically represent reciprocating engines starting by a complete dynamics crankshaft mechanism model which forms the base of the complete engine model. This system is modelled taking into account the possibility of a piston pin offset on the mechanism. The derived Valvetrain model is capable of representing a variable valve lift and phasing Valvetrain which can be used while modelling most modern engines. A butterfly type throttle area model is derived as well as its rate of change which is believed to be a key variable for transient engine control. In addition, an approximation throttle model is formulated aiming at real-time applications. Furthermore, the engine inertia is presented as a mathematical model able to be used for any engine. A spark ignition engine simulation (SIES) framework was developed in MATLAB SIMULINK to form the base of a complete high fidelity cycle-by-cycle simulation model with its major target to provide an environment for virtual engine mapping procedures. Some experimental measurements from an actual engine are still required to parameterise the model, which is the reason an engine mapping (EngMap) framework has been developed in LabVIEW, It is shown that all the moving engine components can be represented by a single cyclic variable which can be used for flow model development.
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Knutsson, Magnus. "IC-engine intake noise predictions based on linear acoustics /." Stockholm : The Marcus Wallenberg Laboratory for Sound and Vibration Research, Royal Institute of Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4586.
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Huang, Xiaodan. "Coupling hybrid CFD models in simulating IC engine flows." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/13063.
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A novel concept which couples ID and 2D CFD models in a simulation of unsteady lC engine flows was investigated, and such a coupled model was developed. Two unified solution procedures which are capable of predicting mixed compressible and incompressible flow fields found in an engine were developed and comparatively studied. One is the pressure correction algorithm, the other is the block implicit algorithm. They provided platforms for the implementation of coupled models. Second order spatial and Euler backward time differencing schemes were adopted. The comprehensive comparative studies were performed on a variety of benchmark flows ranging from steady to unsteady, incompressible to compressible. The data documented have shown that the prediction qualities of the two algorithms were comparable in all calculations. The block implicit procedure required more storage memory generally but it converged faster in all cases except the incompressible flow calculations. General strategies to couple the ID CFD model with the 2D CFD model in one calculation were proposed. They were successfully incorporated in both of the unified solution procedures. The predictions from these coupled models for a series of unsteady benchmark flows were competitive in quality with those from single 2D CFD models, however, the computing costs involved were comparatively much lower. In these calculations, the coupled models integrated in the block implicit procedure produced faster convergence than those in the pressure correction procedure, but required more computing resource. In addition, the implicit coupling stragety was more efficient compared to the explicit counterpart. A ID and 2D coupled model integrated in the pressure correction procedure was applied to simulate a realistic cylinder-valve-pipe flow. The overal prediction quality is satisfactory compared with experimental measurements. Some discrepancies which occurred were largely attributed to numerical representations of valve mechanism and the lack of turbulence models. For this engine application, the coupled model has shown advantages in computing cost or straightforwardness over a conventional uniform 2D model or boundary condition model.
9
Leisenring, Kenneth C. "IC engine air/fuel ratio feedback control during cold-start." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269527559.
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Choi, Woong-Chul. "Characterization of intake generated flow field in an IC engine /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487865929456904.
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Yavuz, Ibrahim. "Refined turbulence models for simulation of IC-engine cylinder flows." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1314.
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Thesis (Ph. D.)--West Virginia University, 2000.<br>Title from document title page. Document formatted into pages; contains xiii, 164 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 153-164).
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Maier, Andreas. "Geometric parameters influencing IC engine inlet valve flow and heat transfer." Thesis, University of Sunderland, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298001.
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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.
15
Barceló, Adrover Salvador. "An advanced Framework for efficient IC optimization based on analytical models engine." Doctoral thesis, Universitat de les Illes Balears, 2013. http://hdl.handle.net/10803/128968.
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En base als reptes sorgits a conseqüència de l'escalat de la tecnologia, la present tesis desenvolupa i analitza un conjunt d'eines orientades a avaluar la sensibilitat a la propagació d'esdeveniments SET en circuits microelectrònics. S'han proposant varies mètriques de propagació de SETs considerant l'impacto dels emmascaraments lògic, elèctric i combinat lògic-elèctric. Aquestes mètriques proporcionen una via d'anàlisi per quantificar tant les regions més susceptibles a propagar SETs com les sortides més susceptibles de rebre'ls. S'ha desenvolupat un conjunt d'algorismes de cerca de camins sensibilitzables altament adaptables a múltiples aplicacions, un sistema lògic especific i diverses tècniques de simplificació de circuits. S'ha demostrat que el retard d'un camí donat depèn dels vectors de sensibilització aplicats a les portes que formen part del mateix, essent aquesta variació de retard comparable a la atribuïble a les variacions paramètriques del proces.<br>En base a los desafíos surgidos a consecuencia del escalado de la tecnología, la presente tesis desarrolla y analiza un conjunto de herramientas orientadas a evaluar la sensibilidad a la propagación de eventos SET en circuitos microelectrónicos. Se han propuesto varias métricas de propagación de SETs considerando el impacto de los enmascaramientos lógico, eléctrico y combinado lógico-eléctrico. Estas métricas proporcionan una vía de análisis para cuantificar tanto las regiones más susceptibles a propagar eventos SET como las salidas más susceptibles a recibirlos. Ha sido desarrollado un conjunto de algoritmos de búsqueda de caminos sensibilizables altamente adaptables a múltiples aplicaciones, un sistema lógico especifico y diversas técnicas de simplificación de circuitos. Se ha demostrado que el retardo de un camino dado depende de los vectores de sensibilización aplicados a las puertas que forman parte del mismo, siendo esta variación de retardo comparable a la atribuible a las variaciones paramétricas del proceso.<br>Based on the challenges arising as a result of technology scaling, this thesis develops and evaluates a complete framework for SET propagation sensitivity. The framework comprises a number of processing tools capable of handling circuits with high complexity in an efficient way. Various SET propagation metrics have been proposed considering the impact of logic, electric and combined logic-electric masking. Such metrics provide a valuable vehicle to grade either in-circuit regions being more susceptible of propagating SETs toward the circuit outputs or circuit outputs more susceptible to produce SET. A quite efficient and customizable true path finding algorithm with a specific logic system has been constructed and its efficacy demonstrated on large benchmark circuits. It has been shown that the delay of a path depends on the sensitization vectors applied to the gates within the path. In some cases, this variation is comparable to the one caused by process parameters variations.
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McIntyre, Dustin L. "The coaxial cavity resonator as a prototype RF IC engine ignition source." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1504.
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Thesis (M.S.)--West Virginia University, 2000.<br>Title from document title page. Document formatted into pages; contains xii, 119 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 106-107).
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Rasheed, Abdul Khaliq. "Heat transfer, tribology and performance of graphene nanolubricants in an IC engine." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/39675/.
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Improving the thermo-physical and tribological properties of lubricants has been a challenging subject of research. Over the last few years, nanolubricants, which are oils containing nanoparticle have been reported to possess exceptionally higher thermal and tribological properties than the traditional lubricants. However, nanolubricants complying with the American Petroleum Institute (API) and Society of Automotive Engineers (SAE) standards remain largely unexplored. In this dissertation, graphene based automotive lubricants meeting 20W50 API SN/CF and 20W50 API SJ/CF specifications have been investigated using a wide range of analytical methods. Thermal-physical and tribological properties have been thoroughly studied. A four-stroke IC engine test rig has been fabricated to investigate the performance of the formulated nanolubricant. By adding 0.01 wt% of 60 nm graphene and 1% lubricity additive to 20W50 API SN/CF oil, 21% and 23% enhancement in the coefficient of friction (μ) and thermal conductivity (k) at 80°C respectively was observed. Viscosity of SNCF with 0.01 wt% of 60 nm graphene and 1% lubricity increases by ~6% at 25°C, and ~9% at 105°C. Scanning electron microscopy and Energy-dispersive X-ray spectroscopy suggest that many nano-tribo mechanisms occurring simultaneously or subsequently could be the reason for enhanced anti-wear and antifriction behaviour of the nanolubricant. Graphene found in the used engine oil indicates that the multilayer graphene exfoliates, rolls up to become helical coils or tube like structure and subsequently entangles with other flakes. As a result, gradually augmenting the thermal performance of the oil. Thermogravimetric analysis revealed that the onset temperature of oxidation for the SN/CF oil could be delayed by 13-17 °C in the presence of graphene. Moreover, the rate of oxidation when the weight loss of oil in the presence of graphene reaches 40% to 20% could be delayed by more than 30 °C. Resistance to oil degradation depends strongly on the graphene nanoparticle size and concentration. TGA kinetics studies show that the base oils have higher activation energy (Ea) and the addition of graphene significantly reduces Ea. Furthermore, 70% enhancement in heat transfer rate is also achieved in the presence of graphene. SEM images of the piston rings collected after 100 hours of engine operation show that the oil containing graphene (12 nm) decreases the piston wear compared to base oil without graphene. Elemental analysis indicates that the addition of a natural polymeric ester based lubricity additive helps even the graphene of highest thickness to perform better in boundary lubrication conditions. Essentially, this research has put forth a comprehensive understanding of a novel graphene based nanolubricant. The consolidated approach to understand tribological mechanism proposed in this research is expected to result in de novo strategies for engineering advanced nanolubricants in future.
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Lauden, Jonathan W. "Experimental Engine Characterization for Spring Design of Novel Automotive Starter." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1366717912.
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Pagano, David. "Hydrogen Powred IC Engine: applicazioni, modifiche e impatto ambientale dei motori a idrogeno." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22332/.
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La tesi si concentra sull'applicabilità e sulle caratteristiche dei motori alimentati ad idrogeno, partendo dal concetto chimico dell'elemento e soffermandosi, poi, sulle nozioni di produzione e stoccaggio. L'aspetto rilevante dello scritto è senz'altro la comprensione tecnica dell'efficacia di tali motori, confrontati con i classici motori a combustione interna, relativamente alla prospettiva di un minore impatto ambientale. Tuttavia, si mette in luce la lunga strada ancora da percorrere in questo ambito, data dalla bassa efficienza, rispetto ai motori tradizionali, e soprattutto, dall'inesistenza di una rete capillare di produzione di idrogeno sul territorio. In conclusione, si evince come la possibilità teorica di superare tali problemi esista e si debba affrontare, affinché il sistema di trasporti riesca a superare le sue barriere economiche e tecnologiche.
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Dunstan, T. D. "Turbulent Premixed Flame Kernel Growth During The Early Stages Using Direct Numerical Simulation." Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/3486.
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In this thesis Direct Numerical Simulation (DNS) is used to investigate the development
of turbulent premixed flame kernels during the early stages of growth typical of the
period following spark ignition. Two distinct aspects of this phase are considered: the
interaction of the expanding kernel with a field of decaying turbulence, and the
chemical and thermo-diffusive response of the flame for different fresh-gas
compositions. In the first part of the study, three-dimensional, repeated simulations with
single-step chemistry are used to generate ensemble statistics of global flame growth.
The surface-conditioned mean fluid-velocity magnitude is found to vary significantly
across different isosurfaces of the reaction progress variable, and this is shown to lead to
a bias in the distribution of the Surface Density Function (SDF) around the developing
flame. Two-dimensional simulations in an extended domain indicate that this effect
translates into a similar directional bias in the Flame Surface Density (FSD) at later
stages in the kernel development. Properties of the fresh gas turbulence decay are
assessed from an independent, non-reacting simulation database.
In the second part of this study, two-dimensional simulations with a detailed 68-step
reaction mechanism are used to investigate the thermo-diffusive response of pure
methane-air, and hydrogen-enriched methane-air flames. The changes in local and
global behaviour due to the different laminar flame characteristics, and the response of
the flames to strain and curvature are examined at different equivalence ratios and
turbulence intensities. Mechanisms leading to flame quenching are discussed and the
effect of mean flame curvature is assessed through comparison with an equivalent
planar flame. The effects of hydrogen addition are found to be particularly pronounced
in flame kernels due to the higher positive stretch rates and reduced thermo-diffusive
stability of hydrogen-enriched flames.
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Brennan, S. L. B. "Coupled 1D and 3D analysis of flow in the intake of an IC engine." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431464.
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Ghiasi, Golnoush. "Simulation of turbulent flames at conditions related to IC engines." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/278054.
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Engine manufacturers are constantly seeking avenues to build cleaner and more ef cient engines to meet ever increasing stringent emission legislations. This requires a closer under- standing of the in-cylinder physical and chemical processes, which can be obtained either through experiments or simulations. The advent of computational hardware, methodologies and modelling approaches in recent times make computational uid dynamics (CFD) an important and cost-effective tool for gathering required insights on the in-cylinder ow, combustion and their interactions. Traditional Reynolds-Averaged Navier-Stokes (RANS) methods and emerging Large Eddy Simulation (LES) techniques are being used as a reli- able mathematical framework tools for the prediction of turbulent ow in such conditions. Nonetheless, the combustion submodels commonly used in combustion calculations are developed using insights and results obtained for atmospheric conditions. However, The combustion characteristics and its interaction with turbulence at Internal combustion (IC) engine conditions with, high pressure and temperatures can be quite different from those in conventional conditions and are yet to be investigated in detail. The objective here is to apply FlaRe (Flamelets revised for physical consistencies) model for IC engines conditions and assess its performance. This model was developed in earlier studies for continuous combustion systems. It is well accepted that the laminar burning velocity, SL, is an essential parameter to determine the fuel burn rate and consequently the power output and ef ciency of IC engines. Also, it is involved in almost all of the sophisticated turbulent combustion models for premixed and partially premixed charges. The burning velocities of these mixtures at temperatures of 850 ≤ T ≤ 950 decrease with pressure up to about 3 MPa as it is well known, but it starts to increase beyond this pressure. This contrasting behaviour observed for the rst time is explained and it is related to the role of pressure dependent reaction for iso-octane and involving OH and the in uence of this radical on the fuel consumption rate. The results iv seem to suggest that the overall order of the combustion reaction for iso-octane and gasoline mixture with air is larger than 2 at pressures higher than 3 MPa. The FlaRe combustion is used to simulate premixed combustion inside a spark-ignition engine. The predictive capabilities of the proposed approach and sensitivity of the model to various parameters have been studied. FlaRe approach includes a parameter βc representing the effects of ame curvature on the burning rate. Since the reactant temperature and pressure inside the cylinder are continually varying with time, the mutual in uence of ame curvature and thermo-chemical activities may be stronger in IC engines and thus this parameter is less likely to be constant. The sensitivity of engine simulation results to this parameter is investigated for a range of engine speed and load conditions. The results indicate some sensitivity and so a careful calibration of this parameter is required for URANS calculation which can be avoided using dynamic evaluations for LES. The predicted pressure variations show fair agreement with those obtained using the level-set approach. DNS data of a hydrogen air turbulent premixed ame in a rectangular constant volume vessel has been analysed to see the effect of higher pressure and temperature on the curvature parameter βc. Since the reactant temperature and pressure inside the cylinder are continually varying with time, the mutual in uence of ame curvature and thermo-chemical activities are expected to be stronger in IC engines and thus the parameter βc may not be constant. To shed more light on this, two time steps from the DNS data has been analysed using dynamic βc procedure. The results show that the effect of higher pressure and temperature need to be considered and taken into account while evaluating βc. When combustion takes place inside a closed vessel as in an IC engine the compression of the un-burnt gases by the propagating ame causes the pressure to rise. In the nal part of this thesis, the FlaRe combustion model is implemented in a commercial computational uid dynamics (CFD) code, STAR-CD, in the LES framework to study swirling combustion inside a closed vessel. Different values of βc has been tested and the need for dynamic evaluation is observed.
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Bergeles, Konstantinos. "Liquid atomisation processes in the crankcase of an IC engine : a computational and experimental study." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/56937.
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The present thesis explores the mechanisms of aerodynamic breakup, jet disintegration and droplet formation inside the crankcase of an internal combustion engine. The work employs advanced experimental and computational tools, which allowed the description and detailed understanding of the flow processes driving liquid atomisation. The literature review identified numerous types of droplet-flow interactions, flow structures and mechanisms which required further investigation. These important parameters are currently ignored in most engineering design. Droplets, upon generation in the crankcase, is shown to be far from spherical, an assumption usually made in the engineering practice. The effect of droplet non-sphericity on its shape evolution and disintegration process was a primary research objective. The experimental part of the work allowed the detailed investigation of droplet-crossflow interactions and its subsequent atomisation for a range of Weber, Ohnesorge numbers and initial droplet aspect ratios. New, equivalent Weber and Ohnesorge numbers, incorporating the initial droplet non-sphericity, are proposed, which are able to classify the breakup of spherical and non-spherical droplets under the morphological classification charts in the literature. Additionally, new empirical correlations are presented for the breakup initiation time and maximum cross-stream droplet diameter. The experiments were further clarified with computational investigations as regards the breakup initiation time, droplet shape evolution and transitional droplet drag coefficient. The computational investigation studied the strength and location of the rollex, which for topological reasons must exist on the droplet – gas rear interface. A novel experimental setup of a rotating disc was manufactured to partially simulate the crankshaft. The jet disintegration modes and droplet formation processes, due to its rotation, are explored and described. Detailed investigation of the effect of the crankshaft rotational speed and liquid flow rate led to the clarification of the disintegration mechanisms and to the study of the breakup length of the liquid jet. Finally, a initiative was undertaken to link light-field imaging with liquid atomisation processes. A plenoptic camera prototype, designed and manufactured in-house, was used in a simplified droplet arrangement. Further to that, an algorithm was developed for the three dimensional reconstruction of the plenoptic images. The results indicated the high potential of the plenoptic concept to multiphase flows.
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Natarajan, Vinod K. (Vinod Kumar) 1979. "The performance of IC engine and fuel cell hybrid propulsion systems in light duty vehicles." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89878.
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Ilie, Katherine-Rodica, and Katherine ilie@rmit edu au. "Modelling, Simulation and Optimisation of Asymmetric Rotor Profiles in Twin-screw Superchargers." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080213.144857.
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There is a growing recognition worldwide of the need for more powerful, smaller petrol engines, capable of delivering the higher picking power of larger engines, yet still being economical and environmentally friendly when used for day-to-day driving. An engineering solution for more efficient engines has been considered by research so far. It has been identified that superchargers can potentially improve the performance of automotive engines; therefore research has focused on developing superchargers and supercharger components with higher efficiency. Of particular interest to the research presented in this thesis has been the twin-screw supercharging compressor with design adapted for automotive use (the twin-screw supercharger). The performance of this supercharger type depends on the volume and total losses of the air flow through the supercharger rotors more than on any other aspects of its behaviour. To accurately predict the efficiency of the twin-screw su percharger for matching a particular engine system, accurate supercharger design is required. The main objective of this research was the investigation of the existing limitations of twin-screw superchargers, in particular leakage and reduced efficiency, leading to the development of optimal asymmetric rotor profiles. This research has been completed in four stages defining an innovative rotor design method. The parametric three-dimensional geometric model of twin-screw supercharger rotors of any aspect ratio was developed. For model validation through visualisation, CAD rotor models with scalable data were generated in commercial CAD software and calibrated experimentally by Laser Doppler Velocimetry (LDV) tests. Calibrated rotor profile data can be transferred into CAD-CFD interface for flow simulation and performance optimisation. Through the application of this new rotor design method, new opportunities are created for the twin-screw supercharger design practice, making it a part of the engineering solution for more efficient engines.
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Wang, Wei. "Conditional Moment Closure Model for Ignition of Homogeneous Fuel/Air Mixtures in Internal Combustion Engines." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1577882100318004.
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Hossain, Md Farhad. "Experimental investigation of thermochemically-derived fuels in a diesel engine." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/115545/1/Md.%20Farhad_Hossain_Thesis.pdf.
Full textAbstract:
This thesis is a comparative study on thermochemical conversion of biomass and waste feedstocks into fuels and is divided into two streams. The first investigates the use of wet microalgae feedstocks, using hydrothermal liquefaction (HTL), to produce biocrude. The second stream explores the use of dry waste tyre feedstocks using Green Distillation Technology (GDT), a modified pyrolysis process, to make tyre oil. An experimental investigation of the physicochemical properties of biocrude oil and tyre oil is made. Finally, the impact of the both fuels on a diesel engine was investigated.
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Fjällman, Johan. "Unsteady simulations of the turbulent flow in the exhaust system of an IC-engine for optimal energy utilization." Licentiate thesis, KTH, Strömningsfysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123086.
Full textAbstract:
This licentiate thesis deals with the ow in pipe bends and radial turbines inan internal combustion engine environment. Looking into the engine bay of apassenger car one cannot avoid noticing all the pipe bends and splits. Duringthe development of internal combustion engines the engine manufacturers arestarting to focus more on simulations than on experiments. This is partly becauseof the reduction in cost but also the reduction in turn around time. This isone of the reasons for the need of more accurate and predictive simulations.By using more complex computational methods the accuracy and predictivecapabilities are increased. The downside is that the computational time isincreasing so the long term goal of the project is to use the results to improvethe predictive capability of the lower order methods used by the industry.By comparing experiments, Reynolds Averaged Navier-Stokes (RANS)simulations, and Large Eddy Simulations (LES), the accuracy of the simulationmethods can be established. The advantages of using LES over RANS for the ows under consideration stems from the unsteadiness of the ow in the enginemanifolds. When such unsteadiness overlaps the natural turbulent spectrum,general RANS models cannot handle the problem specic ow. The thesisconsiders this eect on the chosen numerical model. The LES results have beenshown to be more accurate than the RANS simulations both for global meanvalues and for the uctuating components. The LES calculations have provento predict the mean<br><p>QC 20130603</p>
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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/.
Full textAbstract:
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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Gruenert, Thomas. "Analysis of crankshaft-crankcase interaction for the prediction of the dynamic structural response and noise radiation of IC-engine structures." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/27786.
Full textAbstract:
This thesis presents research work which is concerned with the development of analytical and numerical methods for the dynamic analysis of the crankshaft-crankcase assembly. The effects of interaction of crankshaft and crankcase on the dynamic response of an IC engine block structure are studied. These methods are especially attractive for the simulation of the steady state response of rotating systems with many degrees of freedom which are forced by multiple periodic excitations. A major novelty of the methods is the ability to model the system non-linearities successfully as frequency dependent properties.
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Reyes, Belmonte Miguel Ángel. "Contribution to the Experimental Characterization and 1-D Modelling of Turbochargers for IC Engines." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/34777.
Full textAbstract:
At the end of the 19th Century, the invention of the Internal Combustion Engine
(ICE) marked the beginning of our current lifestyle. Soon after the first ICE
patent, the importance of increasing air pressure upstream the engine cylinders was
revealed. At the beginning of the 20th Century turbo-machinery developments (which
had started time before), met the ICE what represented the beginning of turbocharged
engines. Since that time, the working principle has not fundamentally changed. Nevertheless,
stringent emissions standards and oil depletion have motivated engine developments;
among them, turbocharging coupled with downsized engines has emerged
as the most feasible way to increase specific power while reducing fuel consumption.
Turbocharging has been traditionally a complex problem due to the high rotational
speeds, high temperature differences between working fluids (exhaust gases,
compressed air, lubricating oil and cooling liquid) and pulsating flow conditions. To
improve current computational models, a new procedure for turbochargers characterization
and modelling has been presented in this Thesis. That model divides turbocharger
modelling complex problem into several sub-models for each of the nonrecurring
phenomenon; i.e. heat transfer phenomena, friction losses and acoustic
non-linear models for compressor and turbine. A series of ad-hoc experiments have
been designed to aid identifying and isolating each phenomenon from the others. Each
chapter of this Thesis has been dedicated to analyse that complex problem proposing
different sub-models.
First of all, an exhaustive literature review of the existing turbocharger models
has been performed. Then a turbocharger 1-D internal Heat Transfer Model (HTM)
has been developed. Later geometrical models for compressor and turbine have been
proposed to account for acoustic effects. A physically based methodology to extrapolate
turbine performance maps has been developed too. That model improves
turbocharged engine prediction since turbine instantaneous behaviour moves far from
the narrow operative range provided in manufacturer maps. Once each separated
model has been developed and validated, a series of tests considering all phenomena
combined have been performed. Those tests have been designed to check model
accuracy under likely operative conditions.
The main contributions of this Thesis are the development of a 1-D heat transfer
model to account for internal heat fluxes of automotive turbochargers; the development
of a physically-based turbine extrapolation methodology; the several tests
campaigns that have been necessary to study each phenomenon isolated from others
and the integration of experiments and models in a comprehensive characterization
procedure designed to provide 1-D predictive turbocharger models for ICE calculation.<br>Reyes Belmonte, MÁ. (2013). Contribution to the Experimental Characterization and 1-D Modelling of Turbochargers for IC Engines [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34777<br>TESIS
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Ting, Yew Siang. "A study of upward oil jet impingement on flat and concave heated surfaces and the application to IC engine piston cooling." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/19451.
Full textAbstract:
This thesis presents research on upward pointing oil jets that provide cooling of downward facing heated surfaces. The specific purpose of this research is to improve understanding of the oil jet cooling of internal combustion engine pistons. In this research, the cooling of heated blocks with flat and concave surfaces was investigated. Temperature measurements were obtained using an array of thermocouples embedded inside the heated blocks. A flash illumination and high resolution CCD camera system was used to observe the liquid jet impingement. Observations identified a 'bell-sheet' flow pattern, jet interference, jet splatter and jet breakup which provided insights into the liquid jet impingement processes normally encountered on downwardfacing surfaces. Bespoke contracting-type nozzles were used to produce the jet flow structure. The data from these nozzles were used to generate new empirical correlations for oil jet cooling of downward-facing flat surfaces and for predicting the size 6f impingement. The results obtained from these tests were also used for comparison with cooling jets from production automotive piston cooling nozzles. The research has demonstrated that the effectiveness of oil jet cooling can be affected by preheating the oil and varying the injector size to alter the targeted cooling efficiency, and liquid loss due to jet breakup and splatter. Local heat transfer coefficients were observed to increase when the jet Reynolds number increased. Piston undercrown cooling was studied using a range of oil jet configurations. The cooling rates improved with optimised targeted jets. The results also indicated that the undercrown geometry designs such as crosshatched surfaces, undercrown-skirt and gudgeon-pin boss, were significant for enhancing the local rate of forced convective heat transfer. New empirical correlations were developed from the experimental results that enabled prediction of the heat transfer coefficient and jet impingement size for high Prandtl number liquid jets impinging onto downward-facing surfaces. The heat transfer correlations were developed for normal (θ = 90°) and inclined (θ = 75°, 60° and 45°) jet impingements.
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Haworth, Leanne. "Modelling the effect of condensation and evaporation of water on the transient temperatures inside the exhaust system of an IC engine during a cold start." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4285.
Full textAbstract:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010.<br>AFRIKAANSE OPSOMMING:Die navorsing wat hier uiteengesit word ondersoek die hipotese dat kondensasie
en die gevolglike verdamping van water wat teenwoordig is in die uitlaatgas van
‘n binnebrandenjin, plaasvind in die gedeeltes van die uitlaatstelsel tussen die
uitlaatklep en die katalitiese-omsetter se uitlaat. Daar word verder veronderstel
dat hierdie tweefasevloeieffekte die tydafhanklike temperatuurprofiele in die
uitlaatstelsel beïnvloed, wat moontlik kan lei tot ‘n vertraging in die tydsduur vir
die katalitiese omsetter om temperature van 200-300 °C te bereik, wat nodig is om
noemenswaardige omsetting te bewerkstellig.
Om hierdie veronderstelling te evalueer is ‘n tydafhanklike, eendimensionele
wiskundige model van die termo-vloei gedrag in die uitlaatstelsel gedurende ‘n
koue inwerktreeding, insluitende vogtigheidseffekte, opgestel en opgelos deur van
‘n rekenaaralgoritme gebruik te maak. Warmte- en massaoordragsteorie was
gebruik om die ongestadigde massa-, energie- en
momentumbehoudsvergeleikings te formuleer. Die tweefasige vogeffekte was
gemodelleer deur gebruik te maak van die verhouding tussen warmte- en
massaoordrag, wat verdamping en heterogeniese kondensasie (die kondensasie
van damp teen die pypwand) voorspel as gevolg van die dampdrukgradient tussen
die grootmaat damp en die versadigde damp by die oppervlak van die
vloeistoffilm. Homogene kondensasie (die kondensasie van vloeistof in die vorm
van druppels in die dampstroom) was ook in aanmerking geneem indien die
grootmaatgas temperatuur onder die versadigingstemperatuur van die
grootmaatdamp gedaal het.
’n Eksperimentele ondersoek was gedoen deur van twee enjins gebruik te maak,
’n 1.6 L Volkswagen Bora en ’n 1.6 L Ford RoCam, in die toetsselle van Cape
Advanced Engineering Pty (Ltd). Om die gastemperature so akkuraat moontlik te
meet, was spesiale radiasiegeskermde sensore met vinnige reaksietyd ontwerp en
installer in die pypseksies van die uitlaatstelsels van beide enjins. Die geskermde
sensore het temperature van tot 50 °C hoër as konvensionele termokoppels in
dieselfde areas gemeet. Dit is in koers is met resultate wat deur die
foutbeperkingsteorie, geassosieer met die meet van temperature in vloeïende gas
in uitlaatstelsels, voorspel word.
Vergelyking van die numeriese simulasie met die eksperimenteel gemete
temperature het aangedui dat in dele van die uitlaatstelsel voor die katalitieseomsetter,
die vog min uitwerking het op die termiese gedrag van die stelsel. In
hierdie gedeeltes is die konveksie warmte-oordrag dominant. In die katalitieseomsetter
was die vogeffekte invloedryk. Die eksperimentele resultate toon ‘n
duidelike vroeë toename in die gastemperature, gevolg deur ‘n tydperk van
konstante temperature by nagenoeg die versadigingstemperatuur van die
grootmaatdamp (verwys na as die temperatuurplato) by die katalitiese-omsetter se
kern en uitlaat. Die numeries gesimuleerde gastemperature het ook hierdie gedrag
getoon, maar ‘n baie hoë en skerp piek by die begin van die plato het voorgekom. Hierdie piek was nie te sien by die eksperimentele resultate nie en is toegeskryf
aan nie-ewewigstoestande in die verdampingsproses, wat aandui dat die tempo
van verdamping wat deur die massa-oordragmodel voorspel word te hoog is vir
die model en dat dit verfyn moet word. Verdere ondersoek van die invloed van
die individuele massa-oordragprosesse het getoon dat die homogene kondensasie
die dominante proses is in die vorming van vloeistof in die katalitiese-omsetter.
Heterogeniese kondensasie het plaasgevind, maar ‘n kleiner massa vloeistof is
produseer. Die maksimum hoeveelheid vloeistof wat voorspel is om in die
katalitiese-omsetter te vorm was 12 g/cm wat gelykstaande is aan ‘n film van
0.05.mm dik indien eweredig versprei oor die binneoppervlak van die monoliet.
Daar was in die simulasie gevind dat beide verdamping en kondensasie benodig
word om die temperatuurplato te simuleer, vanwaar die gevolgtrekking gemaak
kan word dat beide prosesse wel plaasvind en dat die eerste stelling in die
oorspronklike hipotese wel geldig is. Daar was egter teen die einde van die
toetsperiode gevind dat beide temperature wat met en sonder vogeffekte simuleer
was, die eksperimentele temperature nagevolg het, wat aandui dat die invloed van
vog beperk is tot die vroeë stadiums van die katalitiese-omsetter se
opwarmingstydperk. Die tweede gedeelte van die hipotese wat veronderstel dat
die voggedrag ‘n vertraging in die tydsduur om omsetting te bewerkstellig
veroorsaak, is dus bevind om ongeldig te wees.
Die wiskundige model wat opgestel is tydens die ondersoek is weens
noodsaaklikheid ‘n vereenvoudigde simulasie van komplekse termo-vloei
prosesse. Dit dien as nuttige grondwerk vir verdere in-diepte ondersoeke en
afronding van die teorie met betrekking tot voggedrag en die uitwerking daarvan
op die tydsafhanklike temperature in ‘n uitlaatstelsel.<br>ENGLISH ABSTRACT: The research presented here investigates the hypothesis that condensation and
subsequent evaporation of water vapour present in the exhaust gas of an internal
combustion engine occur in the sections of the exhaust system between the
exhaust port and the catalytic converter exit. It is further hypothesised that these
two-phase moisture effects influence the transient temperature profiles in the
exhaust system, and potentially cause a delay in the time it takes for the catalytic
converter to reach temperatures of 200-300 °C, which are required for light-off to
occur.
In order to evaluate this hypothesis a transient, one-dimensional mathematical
model of the thermo-fluid behaviour in the exhaust system during a cold start,
including moisture effects, was created and solved by means of a computer
algorithm. Heat and mass transfer theory was used to formulate the unsteady
conservation equations for mass, energy and momentum. The two phase moisture
effects were modelled using the analogy between heat and mass transfer, which
predicts evaporation and heterogeneous condensation (the condensation of vapour
against the pipe wall) due to a vapour pressure gradient between the bulk vapour
and a saturated vapour at the surface of the liquid film. Homogeneous
condensation (the condensation of liquid in the form of droplets in the gas stream)
was also accounted for if the bulk gas temperature dropped below the bulk vapour
saturation temperature.
An experimental investigation was performed using two engines, a 1.6.L
Volkswagen Bora and a 1.6.L Ford RoCam, in the test cells of Cape Advanced
Engineering Pty (Ltd). In order to measure the gas temperatures as accurately as
possible specialised radiation shielded sensors with fast time response were
designed and installed in the pipe sections of the exhaust systems of both engines.
The shielded sensors measured temperatures up 50 °C higher than the
conventional thermocouples installed at the same positions, which is in keeping
with the results predicted by the theory governing errors associated with
temperature measurement in the flowing gas in the exhaust system.
Comparison of the numerically simulated and experimentally measured
temperatures indicated that in the sections of the exhaust system leading up to the
catalytic converter the moisture has little influence on the temperature behaviour
of the exhaust system. In these sections the convective heat transfer is dominant.
In the catalytic converter the moisture effects were found to be influential. The
experimental results clearly show an early rise in the gas temperatures, followed
by a period of constant temperature at approximately the saturation temperature of
the bulk vapour (referred to as the temperature plateau) at the catalytic converter
mid-bed and exit. The numerically simulated gas temperatures also exhibited this
plateau, but an initial very high and sharp peak in the simulated gas temperatures
occurred at the start of the plateau. This was not seen in the experimental results
and is attributed to non-equilibrium in the evaporation process, indicating that the rate of evaporation predicted by the mass transfer model used is too high for this
application and that the model needs to be refined. Further investigation of the
influence of the individual mass transfer processes indicated that the
homogeneous condensation is the dominant process in the formation of liquid in
the catalytic converter. Heterogeneous condensation was found to occur, but
produced a smaller mass of liquid. The maximum amount of liquid predicted to
form in the catalytic converter was 12 g/cm, which translates to a film 0.05 mm
thick if evenly distributed over the inner surface of the monolith.
In the simulation it was found that both evaporation and condensation are needed
in order to simulate the temperature plateau, from which it was concluded that
both these processes do occur and the first statement in the original hypothesis is
valid. However, by the end of the test period temperatures simulated both with or
without the moisture effects closely approached the final temperatures of the
experimental investigation, indicating that the influence of the moisture is limited
to the early stages of the catalytic converter warm-up. The second part of the
hypothesis, postulating that the moisture behaviour caused a delay in the time
taken to reach light-off temperature, is therefore concluded to be invalid.
The mathematical model constructed in this research is by necessity a simplified
solution to complex thermo-fluid processes. It serves as useful groundwork for
further elaboration and refinement of the theory related the moisture behaviour
and its influence on the transient temperatures in the exhaust system.
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Chang, Chi-Yao [Verfasser], C. [Akademischer Betreuer] Tropea, S. [Akademischer Betreuer] Jakirlic, and A. [Akademischer Betreuer] Sadiki. "Development and Validation of Scale-resolving Computational Models Relevant to IC-engine Flow Configurations / Chi-Yao Chang. Betreuer: C. Tropea ; S. Jakirlic ; A. Sadiki." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://d-nb.info/1110980396/34.
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Nebojša, Nikolić. "Razvoj metoda dijagnostike usisnog sistema motora sa unutrašnjim sagorevanjem." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2015. http://www.cris.uns.ac.rs/record.jsf?recordId=94802&source=NDLTD&language=en.
Full textAbstract:
U radu je razvijen jedan matematički model za simuliranje ponašanja nekih važnih radnih parametara motora SUS, kada u njegovom usisnom sistemu postoje neispravnosti tipa: „nepredviđeni ulaz vazduha u usisni kolektor“, „pogrešno očitavanje senzora masenog protoka vazduha“, „pogrešno očitavanje senzora pritiska u usisnom kolektoru“, „pogrešno očitavanje senzora temperature u usisnom kolektoru“ i „umanjen EGR protok“. Na osnovu rezultata ovog modela predložen je novi dijagnostički koncept, u okviru kojeg je razvijen jedan model za prepoznavanje pomenutih neispravnosti. Predloženi koncept je proveren na realnim podacima, prikupljenim ispitivanjem jednog stvarnog motora u laboratorijskim uslovima, pri čemu su dobijeni zadovoljavajući rezultati.<br>A mathematical model capable of simulating some important IC engine operating parameters behavior when a fault in its intake air path exists. The faults considered are of the following types: „air leakage in the intake path“, „faulty mass air flow sensor“, „faulty manifold absolute pressure sensor“, „faulty intake air temperature sensor“ and „clogged EGR pipe“. Relying on the data obtained by the fault simulator, a novel diagnosis concept is proposed. A model for fault detection and diagnosis was developed in the scope of the concept. The proposed concept was tested on the real data collected from an automobile IC engine in the laboratory conditions and satisfying results were obtained.
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Dragan, Adamović. "Model detekcije benzena, toluena, etilbenzena i ksilena u izduvnim gasovima motornih vozila primenom gasne hromatografije u funkciji procene zagađenja ambijentalnog vazduha." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=90997&source=NDLTD&language=en.
Full textAbstract:
U okviru doktorske disertacije opisane su jedinstvene fiziĉko-hemijske karakteristikegrupe supstanci benzena, toluena, etilbenzena i ksilena koje pripadaju istraživanjimanajnovijeg trenda nauĉne javnosti. Posebno su opisane perzistencija ipseudoperzistencija, transport, distribucija i negativan i toksiĉan uticaj na zdravljeĉoveka i životnu sredinu. Sprovedena su eksperimentalna istraživanja zavisnostikoncentracionih nivoa BTEX jedinjenja u izduvnim gasovima i operativnih parametaraeksperimentalnog motora SUS. Na osnovu dobijenih rezultata eksperimentalnihistraživanja definisan je emisioni model BTEX jedinjenja simulacijom kretanjaputniĉkog automobila Fiat Punto Classic u skladu sa NEDC ciklusom koji naodgovarajući naĉin reprezentuje standarde uslove vožnje u evropskim gradovima.<br>In this thesis, the unique physicochemical characteristics of a group of substancesconsisting of benzene, toluene, ethylbenzene and xylene have been described.Special emphasis has been placed on their characteristics of persistence and pseudopersistence,transport, distribution and the negative and toxic influence on humanhealth and the environment. The experimental research of the interdependence of theconcentration levels of BTEX compounds in the exhaust gases and the operationalparameters of the experimental IC engine has been conducted. Based on theexperimental research results, the emission model of the BTEX compounds has beendefined by a simulation of movement of a Fiat Punto Classic passenger car inaccordance with the NEDC cycle, which appropriately represents the standard drivingconditions in European cities. Research conducted within the thesis represents thenewest trend of investigation in the scientific world.
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Tiikoja, Heiki. "Acoustic Characterization of Turbochargers and Pipe Terminations." Licentiate thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92648.
Full textAbstract:
In search for quieter engines there is a need for a better understanding of the acoustic properties of engine intake and exhaust system components. Besides mufflers which have the purpose of reducing pressure pulses originating from the internal combustion (IC) engine, there are many components in a modern car exhaust and intake system, e.g., air-filters, coolers, catalytic converters, particulate filters - all having an effect on the pressure pulses or sound field in the system. In this work the focus is on the turbocharged IC-engine where both, sound scattering (reflection and transmission) and sound generation from automotive turbochargers are studied. In addition, sound reflection from an open ended pipe, such as the tailpipe of an IC-engine exhaust is investigated. Accurate and efficient methods to fully characterize turbochargers by measuring the acoustic two-port have been developed. Compared to earlier work, a number of modifications are suggested for improving the quality of the results. A study on three different automotive turbochargers is also presented, including data for sound scattering for both the compressor and turbine. The results for the transmission of sound, which is of interest for the ability of a turbocharger to reduce noise coming from the engine, is plotted for all tested cases against a dimensionless frequency scale (Helmholtz-number). This makes it possible to generalize the result in order to draw conclusions about the behavior for any turbocharger. The sound generation was also studied and three different methods to estimate the sound power are suggested. The methods were used to investigate sound generation at different operating points and identify source mechanisms for a turbocharger compressor. An accurate method for measuring the reflection of plane acoustic waves from a pipe termination in a duct with hot gas flow has been developed and tested. Representing the acoustical conditions at an exhaust tail-pipe, the data obtained is important for effective modeling of exhaust systems. The experimental results of the reflection coefficient were compared with Munt`s theory on flow duct openings. The measurements were carried out for air jet velocities up to Mach 0.4 and for flow temperatures up to 100°C in order to study temperature effects on the reflection properties. It was concluded, that the experimental results agree well with the Munt theory.
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Rämmal, Hans. "Studies of flow duct acoustics with applications to turbocharged engines." Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10590.
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A number of experimental and theoretical studies, performed in the field of technical flow duct acoustics are presented in this thesis. The acoustical methods treated are implemented on turbocharged IC-engines and engine gas exchange system components. A new method based on the well-known two-load technique has been developed. The method was applied to characterise the source data of various piston-engines with non-linear behaviour including a 6 cylinder turbo-charged truck diesel engine. The source characterisation results were compared to the results obtained using the linear two-load technique. It was demonstrated that the new non-linear multi-load technique gives improved results when the source is slightly non-linear. The use of active one-port models has been tested to characterize an air terminal device (ATD) as a source of flow generated noise. In order to predict the noise generation at different operating points of the device a scaling law was derived and verified. In the experimentally derived scaling law a flow speed dependence of 3 was found for the narrow band spectra, corresponding to a dipole-like behavior of the source in the plane wave range. The proposed technique was validated successfully and the results indicated a good prediction of in-duct sound generation by the air terminal device. Sound reflection from hot flow duct openings has been investigated experimentally. The reflection coefficient was measured for flow temperatures up to 500 ºC and jet velocities up to 108m/s. The results have been compared with famous Munt’s theory. It was concluded that at low Mach number and Helmholz number cases the results agree well with the Munt’s model. This was the first experimental validation of the theory for hot flow conditions. Experimental procedures to determine the sound transmission through automotive turbo-charger compressors were developed and described in detail. An overview of a unique turbocharger testing facility established at KTH CICERO in Stockholm is given. The facility can be used to measure acoustic two-port data for turbo-compressors. Results from measurements on a passenger car turbo-compressor are presented and the influence of operating conditions on the sound transmission is discussed. Current wave action models developed in CMT for computation of the gas exchange processes in I.C. engines have been implemented to determine the acoustic wave transmission through the turbo- compressor. The models are validated with the experimental data and the results are presented for different operating conditions of a Volvo passenger car turbo-compressor.<br>QC 20100809
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Williams, Benjamin Ashley Oliver. "Quantitative laser diagnostics for combustion." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:37ea0034-03ac-4021-80e3-5d72200fbd0e.
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Quantitative Planar Laser Induced Fluorescence (QPLIF) is developed as a diagnostic technique and then applied to a prototype Jaguar optical internal combustion engine. QPLIF derives quantitative, two-dimensional, spatially-resolved measurements of fuel concentration. This work reports the first demonstration of a fully-fractionated surrogate fuel which exhibits all the characteristics of a typical gasoline. This 'pseudo' fuel, developed in association with Shell UK, is blended to accept a fluorescent tracer which may track one of the light, middle or heavy fractions of the fuel, each of different volatility. The traditional weaknesses of PLIF for quantitative measurements are addressed by use of a fired in-situ calibration method, which maps the quantum efficiency of the tracer and concurrently corrects for window fouling and exhaust gas residuals (EGR). Fuel distributions are presented with an estimated super-pixel accuracy of 10% at different operating conditions, and then compared to the computational fluid dynamics (CFD) predictions of an in-house Jaguar model. Fuel/Air Ratios by Laser Induced thermal Gratings (FARLIG) is developed theoretically, and results of validation experiments conducted in a laboratory setting are reported. FARLIG conceptually enables the measurement of fuel concentration, oxygen concentration and temperature within a spatially-localised probe volume. Uniquely, the technique exploits the dominant influence of molecular oxygen on non-radiative quenching processes in an aromatic tracer molecule. The changing character of a model quenching mechanism potentially allows the oxygen concentration in the measurement volume to be derived. Absolute signal strength is used to determine fuel concentration, while the oscillation period of the signal provides a precise measurement of temperature (~0.3% uncertainty), with accuracy limited by knowledge of the gas composition.
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Winkler, Niklas. "Reduced models for flows in IC-engines." Doctoral thesis, KTH, Förbränningsmotorteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-41496.
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The finite response time of the turbocharger is the most notable effect of transient operation on a turbocharged diesel engine. To fulfill future emission requirements, high amounts of transient EGR will be required even though after-treatment devices are being used. This implies that advanced turbocharger systems have to be introduced to enable high boost pressure with improved or at least maintained response time. The increased amount of tuneable parameters from the more advanced turbocharging system will make it difficult and expensive to optimise the engine experimentally. Therefore, the wish is to optimise the engine design using numerical tools. This requires predictive models for the gas exchange system and its components, i.e. the turbocharger, the manifolds and the cylinder with its valves. The results have shown that engine simulation tools based on tabulated data from measurements can qualitatively predict the engine's performance and be used as a first step in engine design. However, these models have to be calibrated extensively in order to reflect the engine performance quantitatively. The objective of this research is therefore to find a modelling approach for the gas exchange system and its components that are more predictive than the tools used, but still computationally effective enough to be suited for engine simulations. The thesis contains a summary of on-engine experimental results as well as some One-Dimensional (1D) simulations. Since the 1D modelling approach has limited range of validity and applicability, we have considered two approaches for reducing the full Three-Dimensional (3D) governing equations, which are a set of Partial Differential Equations (PDE), in a systematic manner. The first approach is based on a numerical length scale analysis of the different terms in the governing equations after changing the coordinate system with one coordinate aligned with the flow path. By retaining the most important terms or neglecting the (significantly) smallest terms, different reductions may be attained, which in their simplest form may look like the boundary layer equations. The results for a double bent pipe, used to illustrate the approach, show that the most significant component of the viscous terms is the radial component, which is in the order of two magnitudes larger than the axial and azimuthal components. The convective terms are all in the same order of magnitude, whereas the radial component is of significant importance in the bends of the pipe due to centrifugal forces, and the azimuthal component after the second bend due to a swirling motion. For the flow in a straight pipe, the approach would give the same model as the common 1D simulation tool. However, for pipes with a more general shape, the approach is superior as it allows for a rational reduction of the governing equations. The main limitation of the approach is for flow situations that do not have a dominating flow direction. Under such conditions the a priori and/or the a posteriori analysis would reveal that the reduction is inconsistent. Thus, the approach implies maintained efficiency, but with improved (and assessable) accuracy as compared to the common 1D simulation tool. The second approach is based on the Galerkin projection of the governing equations projected onto Proper Orthogonal Decomposition (POD) modes. These POD modes are computed for the flow in a given geometry obtained through Large Eddy Simulations (LES). The Galerkin projection results in a system of Ordinary Differential Equations (ODE) for the time-dependent coefficients of the 3D POD modes. The results show that the method is best suited for flows with strong coherent structures. However, the system of ODEs may be inherently unstable (depending on the number of modes used in the simulation) and modelling errors grow with each time-step. This limitation may be remedied by numerically preventing any exponential growth. The approach can also be extended into a combined Galerkin (ODE) - LES (PDE) approach by replacing several steps of the LES by the same amount of time steps with the reduced model. It should be pointed out that this approach can provide the full 3D flow field in contrast to space reduced models (e.g. the common 1D tool) and thereby handle more complex flows with high degree of computational efficiency. To summarize, the thesis demonstrates new possibilities of obtaining reduced models suited for engine simulations based on 3D CFD. With this application in mind, these tools are novel and their evaluation and assessment should be extended to other components of the gas exchange system.<br>QC 20110928
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Madireddy, Madhava Rao. "Analytical design of a parallel hybrid electric powertrain for sports utility vehicles and heavy trucks." Ohio : Ohio University, 2003. http://www.ohiolink.edu/etd/view.cgi?ohiou1175278829.
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Angelis, Yerasimos. "Quantification of environmentally sensitive emissions by substitution of traditional internal combustion (IC) technology with hydrogen fuelled IC engines." Available from the University of Aberdeen Library and Historic Collections Digital Resources. Online version available for University member only until May, 20, 2014, 2007. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26222.
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Johnsson, Roger. "Indirect measurements for control and diagnostics of IC engines /." Luleå, 2004. http://epubl.luth.se/1402-1544/2004/60/index.html.
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Vagenas, Alexios. "Actively controlled cooling jets for application to IC engines." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426146.
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Ma, Jia. "Model-based control of electro-pneumatic intake and exhaust valve actuators for IC engines." Diss., Connect to online resource - MSU authorized users, 2008.
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Thesis (Ph. D.)--Michigan State University. Dept. of Mechanical Engineering, 2008.<br>Title from PDF t.p. (viewed on Mar. 31, 2009) Includes bibliographical references (p. 150-151). Also issued in print.
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Sesler, Josh J. "Implementation of Refractory Foam Technology for Silencing Small IC Engines." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35453.
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With the need for stealth in defense applications steadily increasing, noise reduction
continues to play an important role in the world of aeronautics. With the ever increasing
number of small UAV flight vehicle designs and their stringent weight requirements,
acoustic solutions become progressively more complex. This thesis investigates the use
of refractory foam, a new class of porous material, for designing effective silencers for
small IC engines. The solution must be lightweight, compact, conformable, and capable
of handling the rigors of flight. Throughout the course of this research, many silencer
designs were fabricated to take advantage of refractory foam technology. These silencer
designs were then tested against existing designs using both anechoic and outdoor testing
techniques. These results proved refractory foam to be a superior broadband noise
absorber that can survive harsh flight environment. Silencer designs using this material
showed overall improvements in the areas of noise reduction, weight, size, and
backpressure, compared to commercial designs. The final silencer design boasted an Aweighted
overall sound pressure level that was 12.1 dBA lower than the reference case.
This result was accomplished using nearly half the volume required by other designs to
attain similar results.<br>Master of Science
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Deng, Qiyou. "Dynamic characterisation and 1-D modelling of Turbochargers for IC Engines." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.725400.
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Sakowitz, Alexander. "On the Computation of Turbulent Mixing Processes with Application to EGR in IC-engines." Licentiate thesis, KTH, Mekanik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48138.
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This thesis deals with turbulent mixing processes occuring in internal combustion engines, when applying exhaust gas recirculation (EGR). EGR is a very efficient way to reduce emissions of nitrogen oxides (NOx) in internal combustion engines. Exhaust gases are recirculated and mixed with the intake air of the engine, thus reducing the oxygen concentration of the combustion gas and the maximum combustion tempera- ture. This temperature decrease results in a reduction of NOx emissions, since NOx is produced at high temperatures.The issue of NOx reduction is of high importance for current engine development (particularly for heavy-duty engines), since NOx is the main cause for smog formation and subject to increasingly stronger emission legislation. One of the practical problems when applying EGR is the non-uniformity of the mixture among and inside the cylinders deteriorating the engine and emission performance.The aim of this work is to develop and assess methods suited for the computation of turbulent mixing processes in engine conditions. More specifically, RANS and LES computations are considered. The flow structures responsible for the mixing are analyzed for two different T-junctions and a six-cylinder Scania engine-manifold. Shortcomings and advantages of the applied mixing models are explained.The main results are, that commonly applied scalar flux models for the RANS framework do not predict correct scalar flux directions. In stationary flow, the applied k-ε-model in combination with a gradient-diffusion-model gives too small mixing rates as compared to LES and experiments. Furthermore, the LES computations of the T-junctions show, that Dean vortices occuring due to the curvature of the flow are broken up and dissipated only a few diameters downstream of the junction. The RANS computations do not predict this break-up, giving fundamentally different flow structures and mixing distributions. In pulsating flow, a resonance between the natural stabilities and the pulsation frequency is found by LES results, which could not be predicted by RANS.Computations of the flow in a Scania intake manifold with generic boundary con- ditions indicate, that inlet pulsations are important for the mixing process and that the smoothing effect of URANS is not adequate for accurate mixing computations. LES, on the other hand, is more promising, since it is able to capture the physics of pulsating flows much better.<br>QC 20111117
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Wang, Zheng. "DEVELOPMENT OF ACOUSTIC MODELS FOR HIGH FREQUENCY RESONATORS FOR TURBOCHARGED IC-ENGINES." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91335.
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Automotive turbo compressors generate high frequency noise in the air intake system. This sound generation is of importance for the perceived sound quality of luxury cars and may need to be controlled by the use of silencers. The silencers usually contain resonators with slits, perforates and cavities. The purpose of the work reported is to develop acoustic models for these resonators where relevant effects such as the effect of realistic mean flow on losses and possibly 3D effects are considered. An experimental campaign has been undertaken where the two-port matrices and transmission loss of four sample resonators has been measured without flow and for two different mean flow speeds (M=0.05 & M=0.1) using two source location technique. Models for the four resonators have been developed using a 1D linear acoustic code (SIDLAB) and a FEM code (COMSOL Multi-physics). Different models, from the literature, for including the effect of mean flow on the acoustic losses at slits and perforates have been discussed. Correct modeling of acoustic losses for resonators with complicated geometry is important for the simulation and development of new and improved silencers, and the present work contributes to this understanding. The measured acoustic properties compared well with the simulated model for almost all the cases.
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Kumar, A. "Investigation of in-nozzle flow characteristics of fuel injectors of IC engines." Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/17583/.
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Almost all automotive fuel injection systems are experiencing some form of cavitation within their nozzle under different operating conditions. In-nozzle cavitation initiates in various forms and directly influences the emerging spray. Experimental studies have shown that cavitation in diesel injectors leads to smaller droplet formation, especially by the on-going trend towards higher injection pressures, which enhances fuel evaporation but also creates undesirable consequences due to transient nature of cavitation such as spray instabilities, erosion on internal surfaces, and hydraulic flip. Thus, the understanding of the internal flow of automotive fuel injectors is critical for injector design. On the other hand, biodiesel has emerged as one of the potential alternative fuel which can also be carbon neutral because it uptakes CO2 during cultivation of its feedstock and can be used in existing diesel engines with little or no modifications. Therefore, the present study is focused on assessing and outlining cost-effective methods to analyse internal flow in fuel injectors for diesel and biodiesel fuel applications. In the present study, RANS-based (Reynolds-averaged Navier–Stokes) CFD (Computational fluid dynamics) approach has been chosen to simulate quasi-steady flows in the steady state test rigs of fuel injectors of IC engines. The RANS approach is selected over computationally expensive SAS (Scale Adaptive Simulations), DES (Detached Eddy Simulations) and LES (Large Eddy Simulations) because it was considered that these quasi-steady simulations could be performed within hours and with less computing resources using RANS rather using SAS, DES and LES which may require orders more time and computing resources. Cavitation models and RANSbased turbulence models have been evaluated for single-hole and multi-hole injectors operating on steady state test rigs. Furthermore, influences of liquid and vapour compressibility were also investigated. Influences of biodiesel properties such as higher viscosity and density on cavitation were also assessed. In the first part of the study, single-phase simulations have been carried out in the mini-sac type multi-hole (6) injector. Several two-equation turbulence and near wall models were assessed, amongst most appropriate for the application were identified. Predicted mean velocity and RMS velocity were compared with measurements and showed good agreements. Flow field analysis showed predictions of different types of vortices in the injector. Two main types of vortex structures were predicted: ‘Hole-to-hole’ connecting vortex and double ‘counterrotating’ vortices emerging from the needle wall and entering the injector hole facing it. The latter create a complex 3D flow inside the injector hole when it interacts with the recirculation region at the entrance of the injector hole. Cavitation simulations inside a single-hole injector were next performed. Simulations were assessed by comparing predicted vapour volume fraction with measurements. Influences of liquid and vapour compressibility were also checked. The compressibility of vapour was modelled using ideal gas law and liquid compressibility was modelled using the Tait equation. Vapour compressibility resulted in an increase of vapour volume fraction at the low-pressure region and predictions were also in better agreements with experimental data. The liquid compressibility made no impact on the simulation results. The local sonic speed in the liquid-vapour mixture was computed using Wallis model which predicted a very low local sonic speed in the liquid-vapour mixture. Therefore, the local flow in liquid-vapour mixture became supersonic. A normal shock wave was predicted just downstream of the cavitation bubble cloud as local flow velocity was reduced from supersonic to subsonic. Finally, the cavitation simulations were performed in the enlarged mini-sac type multi-hole injector. Established turbulence, cavitation and compressibility models from above studies were used. Reasonable quantitative agreements with experimental data were obtained for the mean axial velocity and RMS velocity. Reasonable qualitative agreements were also achieved when predicted cavitation results were compared with high-speed digital images. Henceforth a parametric study to assess the influence of biodiesel fuel properties such as an increase in viscosity and density on the cavitation was performed. Viscosity and density of both phases in the fluid were parametrically increased by 20%. Results showed that cavitation was suppressed when the viscosity was increased because it increased the flow resistance, thus reduced the velocity. This caused a reduction in the size of recirculation region at the entrance of the injector hole and hence a smaller saturation pressure region was predicted. Cavitation was further suppressed when density was increased causing the reduction in the velocity at the same mass flow rate, which further reduced the recirculation region, therefore, reduced the saturation pressure region and consequently cavitation.