Dissertations / Theses: 'Machine pistols'

1

Salquebre, Quentin. "Développement d'un modèle de prédimensionnement d'un ensemble alternateur - machine Stirling à pistons libres." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT015/document.

Full text

Abstract:

Le moteur Stirling a été développé il y’a 200 ans. Cependant son développement n’a jamais connu un grand essor. Le contexte énergétique actuel a relancé l’intérêt porté à ces machines. En effet la possibilité de le faire fonctionner à partir de n’importe quelle source de chaleur externe lui permet d’être associé à des sources d’énergie renouvelable comme l’énergie solaire. Au-delà des avantages écologiques, le développement par W. Beale à la fin des années 1960 d’un moteur Stirling à pistons libres (ou FPSE pour Free Piston Stirling Engine) a ajouté de nouveaux intérêts à un tel moteur. Cette nouvelle architecture permet au moteur de fonctionner sans système d’entrainement des pistons. Dans de telles machines, le mouvement des pistons n’est plus déterminé par la géométrie du système d’entrainement. Ces derniers sont mis en mouvement par les forces de pressions occurrents à l’intérieur du moteur. La dynamique des pistons et la thermodynamique du système sont alors couplées, rendant plus complexe la modélisation complète du système.Cette thèse présente une nouvelle technique de modélisation des machines Stirling à pistons libres, intitulée LHA5V pour Linear Harmonic Analysis 5 Volumes, permettant de coupler la thermodynamique du système et la réponse mécanique des pistons libres. Celle-ci repose alors sur la décomposition du moteur Stirling en cinq sous systèmes ouverts : deux espaces à volume variables, deux échangeurs de chaleur et le régénérateur. Nous supposons que les variables d’état varient périodiquement et le modèle détermine comment celles-ci varient en valeur moyenne, en amplitude et en phase afin de satisfaire les équations de conservation de la masse et de l’énergie. L’aspect innovant du modèle thermique repose sur la prise en compte implicite des pertes inhérentes au fonctionnement. Celles-ci ont en effet un impact direct sur le mouvement des pistons. Par ailleurs cette thèse présente également un modèle de génératrice électrique linéaire pouvant être couplé à la partie thermique. Le modèle électrique repose sur un calcul analytique de la force de poussée du stator sur la partie mobile. Le calcul des flux et du niveau d’induction dans le circuit magnétique est effectué à partir d’un réseau de perméances judicieusement paramétré.Que ce soit pour la modélisation thermique ou la modélisation électrique, chacun des modèles a été conçu pour avoir un temps de calcul faible, tout en restant le plus précis possible sur la prédiction des performances. Ceux-ci ont à chaque fois été confrontés à des données expérimentales, ou à d’autres techniques de modélisation plus fines de façon concluante
Though the Stirling engine was invented two centuries ago, it has never really grown to a fully marketable level. The current energy context has renewed the interest in this engine. Their ability to work with any external source of heat allow them to be associated with renewable energy such as solar energy. Beyond its ecological benefits, the invention of the free piston Stirling engine by W. Beale at the end of the 1960’s further increased the interest in Stirling engines. This novel structure allows the engine to operate without mechanical interface between pistons, which are driven entirely by the gas or other spring forces. In such engines, the pistons kinematics and the system thermodynamics are intimately coupled, thus increasing the complexity of the complete system computer modelling.This PhD presents an innovative technique to model a free piston Stirling engine that takes into account the coupling between the system thermodynamics and the mechanical response of the free pistons. This technique has been named LHA5V standing for Linear Harmonic Analysis 5 Volumes. It consists in splitting the engine in five open sub-systems: the compression and expansion spaces, the heater, the cooler and the regenerator. We hypothesize that the state variables are periodic, and the model then determines the variations of their mean, amplitude and phase values in order to satisfy the mass and energy conservation equations. This PhD also presents a model for a linear electric alternator, which can be coupled to the power piston. This electrical model is based on an analytical calculation of the thrust between the stator and the magnets. Magnetic flux and induction in the iron are determined by a carefully tuned reluctance network.Both thermal and electrical models have been designed to optimize both computing time and accuracy. The models generated have systematically been compared to experimental data or finite element analysis, with satisfactory results

APA, Harvard, Vancouver, ISO, and other styles

2

Löfstrand, Grip Rasmus. "A mechanical model of an axial piston machine." Licentiate thesis, KTH, Machine Design (Div.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10948.

Full text

Abstract:

A mechanical model of an axial piston-type machine with a so-called wobble plate and Z-shaft mechanism is presented. The overall aim is to design and construct an oil-free piston expander demonstrator as a first step to realizing an advanced and compact small-scale steam engine system. The benefits of a small steam engine are negligible NOx emissions (due to continuous, low-temperature combustion), no gearbox needed, fuel flexibility (e.g., can run on biofuel and solar), high part-load efficiency, and low noise. Piston expanders, compared with turbines or clearance-sealed rotary displacement machines, have higher mechanical losses but lower leakage losses, much better part-load efficiency, and for many applications a more favourable (i.e., lower) speed. A piston expander is thus feasible for directly propelling small systems in the vehicular power range. An axial piston machine with minimized contact pressures and sliding velocities, and with properly selected construction materials for steam/water lubrication, should enable completely oil-free operation. An oil-free piston machine also has potential for other applications, for example, as a refrigerant (e.g., CO₂) expander in a low-temperature Rankine cycle or as a refrigerant compressor.

An analytical rigid-body kinematics and inverse dynamics model of the machine is presented. The kinematical analysis generates the resulting motion of the integral parts of the machine, fully parameterized. Inverse dynamics is applied when the system motion is completely known, and the method yields required external and internal forces and torques. The analytical model made use of the “Sophia” plug-in developed by Lesser for the simple derivation of rotational matrices relating different coordinate systems and for vector differentiation. Numerical solutions were computed in MATLAB. The results indicate a large load bearing in the conical contact surface between the mechanism’s wobble plate and engine block. The lateral force between piston and cylinder is small compared with that of a comparable machine with a conventional crank mechanism.

This study aims to predict contact loads and sliding velocities in the component interfaces. Such data are needed for bearing and component dimensioning and for selecting materials and coatings. Predicted contact loads together with contact geometries can also be used as input for tribological rig testing. Results from the model have been used to dimension the integral parts, bearings and materials of a physical demonstrator of the super-critical steam expander application as well as in component design and concept studies.

APA, Harvard, Vancouver, ISO, and other styles

3

Löfstrand, Grip Rasmus. "A mechanical model of an axial piston machine." Stockholm : Skolan för industirell teknik och management, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10948.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Wondergem, Ashley, and Monika Ivantysynova. "The Impact of Micro-Surface Shaping of the Piston on the Piston/Cylinder Interface of an Axial Piston Machine." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200169.

Full text

Abstract:

Axial piston machines of the swashplate type are commonly used in various hydraulic systems and with recent developments in displacement control, it is essential to maximize their efficiency further reducing operation costs as well as improving performance and reliability. This paper reports findings of a research study conducted for the piston-cylinder interface utilizing a novel fluid structure thermal interaction model considering solid body deformation due to thermal and pressure effects in order to accurately predict the transient fluid film within the gap. A large reduction in energy dissipation is possible due to reduced clearances allowable due to the surface shaping of the piston resulting in a reduction in leakage. From this study, it is shown that surface shaping of the piston in combination with a reduced clearance is not only beneficial by improving the efficiency of a machine, but also increases the reliability and the performance of the machine as the load support is enhanced.

APA, Harvard, Vancouver, ISO, and other styles

5

Nunio, François. "Contribution à l'étude du comportement dynamique de compresseur à pistons alternatifs." Lille 1, 1993. http://www.theses.fr/1993LIL10100.

Full text

Abstract:

Un modèle de calcul des sollicitations appliquées aux éléments du mécanisme d'un compresseur à pistons alternatifs est construit. La chaîne cinématique est modélisée dans son ensemble (moteur, accouplement et compresseur) et son comportement est abordé de façon dynamique, sans linéarisation des équations du mouvement ; la géométrie des éléments n'est pas simplifiée. La formulation dynamique du problème permet de quantifier les variations des sollicitations induites par le comportement dynamique en torsion de la ligne d'arbre, tant lors des phases de fonctionnement stationnaire (irrégularité cyclique) qu'instationnaire (démarrage, arrêt. . . ). La prise en compte des frottements secs et visqueux permet de dresser le bilan énergétique des pertes mécaniques dans le compresseur. Une analyse de sensibilité aux paramètres du calcul a permis de cerner les limites du modèle et les résultats obtenus par ce calcul ont été validés lors d'une campagne de mesures.

APA, Harvard, Vancouver, ISO, and other styles

6

Bhari, Anil. "A Rapid Compression Machine with the Novel Concept of Crevice Containment." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1294677850.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Kayani, Omer Khaleeq, and Muhammad Sohaib. "Generic Simulation Model Development of Hydraulic Axial Piston Machines." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76575.

Full text

Abstract:

This master thesis presents a novel methodology for the development of simulation models for hydraulic pumps and motors. In this work, a generic simulation model capable of representing multiple axial piston machines is presented, implemented and validated. Validation of the developed generic simulation model is done by comparing the results from the simulation model with experimental measurements. The development of the generic model is done using AMESim. Today simulation models are an integral part of any development process concerning hydraulic machines. An improved methodology for developing these simulation models will affect both the development cost and time in a positive manner. Traditionally, specific simulation models dedicated to a certain pump or motor are created. This implies that a complete rethinking of the model structure has to be done when modeling a new pump or motor. Therefore when dealing with a large number of pumps and motors, this traditional way of model development could lead to large development time and cost. This thesis work presents a unique way of simulation model development where a single model could represent multiple pumps and motors resulting in lower development time and cost. An automated routine for simulation model creation is developed and implemented. This routine uses the generic simulation model as a template to automatically create simulation models requested by the user. For this purpose a user interface has been created through the use of Visual Basic scripting. This interface communicates with the generic simulation model allowing the user to either change it parametrically or completely transform it into another pump or motor. To determine the level of accuracy offered by the generic simulation model, simulation results are compared with experimental data. Moreover, an optimization routine to automatically fine tune the simulation model is also presented.

APA, Harvard, Vancouver, ISO, and other styles

8

Schleihs, Christian [Verfasser]. "Acoustic Design of Hydraulic Axial Piston Swashplate Machines / Christian Schleihs." Aachen : Shaker, 2017. http://d-nb.info/1138177202/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Ferreira, Laércio. "Projeto e construção de uma bomba de pistões axiais swashplate /." Guaratinguetá : [s.n.], 2004. http://hdl.handle.net/11449/97124.

Full text

Abstract:

Orientador: João Zangrandi Filho
Banca: Fernando de Azevedo Silva
Banca: Messias Borges Silva
Resumo: A bomba de pistões axiais tipo swashplate é uma máquina relativamente nova nas aplicações industriais. Uma pesquisa para se obter informações de funcionamento dessa máquina revelou que pouco existe na literatura especializada, a menos de um trabalho de tese de doutorado apresentado na UNESP em 1993. Este trabalho desenvolve procedimento para o projeto de máquinas de pistões axiais e segue uma metodologia para se obter o desenho de conjunto, os detalhes, os ajustes e montagem desta máquina. Em seguida foi feito um estudo para proceder às etapas de usinagem desta máquina, utilizando máquinas convencionais e máquinas de controle numérico. O trabalho visa também fazer com que esta máquina funcione bombeando óleo. O objetivo é garantir com que o mecanismo funcione perfeitamente e não a pressões elevadas.
Abstract: The swashplate piston pump is relatively new in industrial applications. A literature research for obtaining the operation principles of such machines, revealed that little is published in the specialized literature but a work presented as a thesis research at UNESP in 1993. This work presents a procedure for the design of axial piston machines and a methodology in order for one to obtain the cutaway view, the detailed drawings, the fit process and how to assemble this machine. After a long discussion, a detailed process was accomplished in order to develop the machining phases, making use of conventional machines and CNC ones. The present work also declare how this machine will be running along the tests: a way that only the pumping action is required. At this point only the well running and not the pressure value is important.
Mestre

APA, Harvard, Vancouver, ISO, and other styles

10

Carvalho, Robson Flores de [UNESP]. "Projeto e construção de um motor de pistões axiais de vazão fixa." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/97112.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12Bitstream added on 2014-06-13T20:37:39Z : No. of bitstreams: 1 carvalho_rf_me_guara.pdf: 1480284 bytes, checksum: c7e8cc63c757c4ed4fc23810d1bdaa7c (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Projetar e construir máquinas de pistões axiais são atividades desenvolvidas por poucas empresas no mundo. No Brasil, não se conhece nenhum projeto sobre este tipo de máquina até agora, isto é, um projeto totalmente nacional, apenas são manufaturadas utilizando mão de obra brasileira. Este tipo de máquina tem grande aplicação na área industrial, móbile e aeronáutica. Desenvolver este trabalho é o grande desafio, tendo em vista conquistar tecnologia sobre este produto e, conseqüentemente, livrar-se da dependência tecnológica de outros países. Sendo assim este trabalho procura ir mais longe, pois pretende substituir diretamente os motores comerciais em funcionamento numa etapa muito próxima e subseqüente. Calcular e desenhar uma máquina não são etapas suficientes para que ela funcione e ocupe lugar no mercado. Portanto, um estudo minucioso sobre como cada peça deveria ser usinada foi elaborado, e posteriormente discutido com operadores de máquinas. Esta etapa precisa ser considerada tão importante quanto necessária. Este trabalho além de apresentar um histórico da evolução da hidrostática, também mostra com figuras o funcionamento dos motores de pistões axiais. Um roteiro de cálculos relata como as dimensões da máquina foram determinadas, com a finalidade de se obter o desenho de conjunto.
Designing and manufacturing axial piston Swashplate machines are activities that few companies have developed around the world. So far, nothing has been known related to this kind of machine when the focus is on a true national design. In addition, Swashplate machines are fully utilized in industrial, mobile and aeronautical area. Developing this work is the challenge, looking forward to conquer technology in order to manufacture such a product and, consequently, be free from paying royalties to other countries. In this way, the present work goes beyond when one intends to directly substitute those commercial machines in a well next time, it means, just after this work has finished. Calculating and drawing are not sufficient steps to have a machine running. So, a well detailed study was set up in order to know how the parts would be machined and treating and discussing with machine operators was necessary. One should remind that this is a step as important as well necessary. This work presents the history of hydrostatic machines and an explanation relating how the Swashplate motor works. Some calculations are also presented in order to have the assembled view drawing of this machine accomplished.

APA, Harvard, Vancouver, ISO, and other styles

11

Nataraja, H. S. "Improvement Of Piston Ring Quality : A Case Study." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/198.

Full text

Abstract:

Automobiles have become an integral part of our daily life as more and more mopeds, motor cycles, cars, trucks, busses and trains are being used for transport. The main parts of an automotive engine are cylinder, piston assembly, connecting rod and crank shaft. The piston assembly consists of Piston, Piston rings and Piston Pin. Piston rings are important parts of a piston assembly. Any non-conformance in any quality characteristic of the piston ring leads to deterioration of engine performance. M/S Goetze (India) Limited a medium scale industry and a sister concern of engineering giant M/S Escorts Limited is manufacturing "GOETZE PISTON RINGS" and is producing about 800 varieties of piston rings ranging from 35.00 mm to 228.5 mm nominal diameter. The management was facing serious problem due to high scrap rate in certain types of their manufactured piston rings. Hence instead of trying to handle all of them at the same time, it seemed reasonable to tackle and find a suitable approach to solve the quality problem by taking the most notorious ring first, so that once the methodology is understood, documented and applied to the quality problem of this ring, the same can also be invoked for other rings to improve upon their quality, and thus reducing the scrap rate. One particular ring of 83.0 mm diameter which is delicate and costly, having an average scrap rate of 36.2% in past three years is selected for the study. No systematic effort was made in the past to identify the quality characteristics and the processes which were responsible for this high scrap rate and thus no immediate measure could be recommended. As a matter of fact at the beginning of the study it was not even clear which quality characteristics were mainly responsible for such high rejection. So in July' 1999 a pareto analysis was done for the first time to identify the culpability of each quality characteristic for the rejection of the ring. From the Pareto analysis it was observed that maximum proportion of rejection was due to nonconformity in axial thickness. The scrap rate due to nonconformity in axial thickness were collected for each month from Jul’ 999 to Jan'2000 which averaged at 8.7%. Since in every month the major malefactor for rejection was the nonconformity of axial thickness it was decided to first try to improve the quality of axial thickness, before trying to tackle other quality issues associated with this particular piston ring under study. Once the most problematic quality characteristic namely the axial thickness was identified, as a first step towards the goal of improving the quality of axial thickness, it was necessary to pay attention and isolate the manufacturing processes or operations affecting the axial thickness and study them in detail. So first, the entire manufacturing process flow diagram of the piston ring was studied. From the process flow diagram it appeared that there are 4 operations affecting axial thickness viz. Rough Grinding ,Medium Grinding, First Lapping and Finish Lapping. So each of these processes was critically observed to assess whether they were under statistical control or not. Studies were conducted at each of these 4 operations by collecting samples using the rational subgroup method and control charts were plotted. From the control charts, it was observed that the Rough Grinding and Medium Grinding operations were in statistical control with acceptable Cp, Cpk values. But First Lapping and Finish Lapping operations were not in statistical control. Thus we finally identified the two critical processes namely the First Lapping and Finish Lapping operations which were not in statistical control but were crucially affecting the quality of axial thickness. Since the First and Finish Lapping operations were identified as the major source of the quality problem, an in-depth study was undertaken to analyze these two processes. A brain storming session was conducted with all concerned personnel from production, maintenance, design, quality assurance and tool room to get all possible causes which might be affecting the axial thickness variation at these two processes. During the brain storming session the team suggested that the First Lapping process can be processed in medium grinding machine (DFS machine) instead of Lapping machine. The reasons behind this were two fold. First since the aim of the First Lapping is just to remove excess material which was deposited during chrome plating, the same operation can be performed in DFS machine. Since the required surface finish on axial surface was any way being aimed at the Finish Lapping operation, a similar precursory First Lapping'operation in a Lapping machine was really felt not necessary. Secondly since the performance of the DFS machine was found to be under control, albeit for the grinding operation, it was hoped that the Lapping operation in the same machine would also exhibit a similar performance. For this purpose a study was conducted on the First Lapping operation with the DFS machine. It was found that the process was well within the control limit with decent Cp and Cpk values. Thus this procedure of performing the First Lapping operation in a DFS machine took care of the first one of the two problematic processes affecting the quality of axial thickness. Next for tackling the problem with the other critical process, viz. the Finish Lapping operation, various causes were suggested by the team for axial thickness variation in the Finish Lapping operation. Based on these causes, an Ishikawa diagram (cause and effect diagram) was prepared. This Ishikawa diagram had thrown light into number of possible deficiencies in Man, Machine, Method and Material which were responsible for axial thickness variation at finish Lapping. The Ishikawa diagram was carefully analyzed. The causes were narrowed down to 6 factors. These are Grinding wheel rotating speed, Grinding Time, Grinding pressure, Holding plate, Holes (fixtures) within the holding plate and Positions within a ring. The 3 factors namely grinding wheel speed, time and pressure were identified as the control factors. Holding plate, Hole position within a plate and Checking position within a ring on the other hand were the noise factors whose different levels might exhibit a variability of axial thickness. Since there were only 3 control factors, it was decided to conduct a full factorial experiment with each control factor at 3 levels. Hence altogether there were 27 experiments at a fixed given combination of speed, time and pressure. There were 4 holding plates with each plate having 6 slotted holes leading to machining 24 rings at a time during the finish lapping operation. Next 3 measurements were taken for each one of these 24 rings. Thus altogether there were 72 observations for one of these experiments. Each experiment was replicated twice by taking measurements for 2 consecutive batches of rings. From the analysis of variance of the results of these experiments for both S/N ratio and mean it was observed that all the three main factors and their interactions were significant. The Normality assumption of standardized residuals for the S/N ratio and mean was validated by normal probability plot and Kolmonogorov-Smirnoff test. The homoscedasticity assumption was validated through Bartlett’s test and residual plots. It was found that the experiment no. 23 (Speed 84 RPM, Time 10 sees and Pressure 300 daN) yielded highest S/N ratio (η) with mean within the specification limit. That the mean and S/N ratio for the experiment no.23 were significantly different from others was established by means of Tukey's multiple comparison test. Next control charts for experiment no. 23 were plotted and was found to be well within control with acceptable Cp and Cpk values. Hence we concluded that the non-conformance in axial thickness can be substantially reduced by using the following optimal setting of factors i.e. grinding speed with 84 RPM, grinding pressure with 300 daN and grinding time with 10 seconds. Using this optimal setting the earlier average rejection rate of 8.7% due to non-conformance in axial thickness was reduced to 0.05%. Under this optimal setting, the process capability index (Cpk) of finish Lapping operation was estimated to be 2.5, which is well above acceptable standard. Due to this reduction in rejection rate in one quality characteristics of one particular ring out of 800 types, the net savings to the organization is approximately Rs. 10,44,000 per year.

APA, Harvard, Vancouver, ISO, and other styles

12

Ferreira, Laércio [UNESP]. "Projeto e construção de uma bomba de pistões axiais swashplate." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/97124.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-01Bitstream added on 2014-06-13T20:48:20Z : No. of bitstreams: 1 ferreira_l_me_guara.pdf: 2176881 bytes, checksum: 8f2778a638b354767b4b063574bf7559 (MD5)
Universidade Estadual Paulista (UNESP)
A bomba de pistões axiais tipo swashplate é uma máquina relativamente nova nas aplicações industriais. Uma pesquisa para se obter informações de funcionamento dessa máquina revelou que pouco existe na literatura especializada, a menos de um trabalho de tese de doutorado apresentado na UNESP em 1993. Este trabalho desenvolve procedimento para o projeto de máquinas de pistões axiais e segue uma metodologia para se obter o desenho de conjunto, os detalhes, os ajustes e montagem desta máquina. Em seguida foi feito um estudo para proceder às etapas de usinagem desta máquina, utilizando máquinas convencionais e máquinas de controle numérico. O trabalho visa também fazer com que esta máquina funcione bombeando óleo. O objetivo é garantir com que o mecanismo funcione perfeitamente e não a pressões elevadas.
The swashplate piston pump is relatively new in industrial applications. A literature research for obtaining the operation principles of such machines, revealed that little is published in the specialized literature but a work presented as a thesis research at UNESP in 1993. This work presents a procedure for the design of axial piston machines and a methodology in order for one to obtain the cutaway view, the detailed drawings, the fit process and how to assemble this machine. After a long discussion, a detailed process was accomplished in order to develop the machining phases, making use of conventional machines and CNC ones. The present work also declare how this machine will be running along the tests: a way that only the pumping action is required. At this point only the well running and not the pressure value is important.

APA, Harvard, Vancouver, ISO, and other styles

13

Carvalho, Robson Flores de. "Projeto e construção de um motor de pistões axiais de vazão fixa /." Guaratinguetá : [s.n.], 2006. http://hdl.handle.net/11449/97112.

Full text

Abstract:

Orientador: João Zangrandi Filho
Banca: Jose Elias Tomazini
Banca: Carlos Antonio Reis Pereira Baptista
Resumo: Projetar e construir máquinas de pistões axiais são atividades desenvolvidas por poucas empresas no mundo. No Brasil, não se conhece nenhum projeto sobre este tipo de máquina até agora, isto é, um projeto totalmente nacional, apenas são manufaturadas utilizando mão de obra brasileira. Este tipo de máquina tem grande aplicação na área industrial, móbile e aeronáutica. Desenvolver este trabalho é o grande desafio, tendo em vista conquistar tecnologia sobre este produto e, conseqüentemente, livrar-se da dependência tecnológica de outros países. Sendo assim este trabalho procura ir mais longe, pois pretende substituir diretamente os motores comerciais em funcionamento numa etapa muito próxima e subseqüente. Calcular e desenhar uma máquina não são etapas suficientes para que ela funcione e ocupe lugar no mercado. Portanto, um estudo minucioso sobre como cada peça deveria ser usinada foi elaborado, e posteriormente discutido com operadores de máquinas. Esta etapa precisa ser considerada tão importante quanto necessária. Este trabalho além de apresentar um histórico da evolução da hidrostática, também mostra com figuras o funcionamento dos motores de pistões axiais. Um roteiro de cálculos relata como as dimensões da máquina foram determinadas, com a finalidade de se obter o desenho de conjunto.
Abstract: Designing and manufacturing axial piston Swashplate machines are activities that few companies have developed around the world. So far, nothing has been known related to this kind of machine when the focus is on a true national design. In addition, Swashplate machines are fully utilized in industrial, mobile and aeronautical area. Developing this work is the challenge, looking forward to conquer technology in order to manufacture such a product and, consequently, be free from paying royalties to other countries. In this way, the present work goes beyond when one intends to directly substitute those commercial machines in a well next time, it means, just after this work has finished. Calculating and drawing are not sufficient steps to have a machine running. So, a well detailed study was set up in order to know how the parts would be machined and treating and discussing with machine operators was necessary. One should remind that this is a step as important as well necessary. This work presents the history of hydrostatic machines and an explanation relating how the Swashplate motor works. Some calculations are also presented in order to have the assembled view drawing of this machine accomplished.
Mestre

APA, Harvard, Vancouver, ISO, and other styles

14

Haynes, Jonathan Mark. "Axial piston pump leakage modelling and measurement." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/55178/.

Full text

Abstract:

This thesis is concerned with the dominant leakage characteristics of an axial piston pump. Results have been obtained from a combination of analysis, Computational Fluid Dynamics (CFD) and experimental work, and have added to existing knowledge in this field. The measurement of slipper leakage within an axial piston pump is impossible due to additional leakage from the pistons and between the cylinder barrel and port plate. It may only be determined by analysis and this aspect has been studied via a new CFD simulation. Further progress has been made experimentally on slipper leakage. A new test apparatus was designed and developed by the author and comparisons have been made with parallel analytical work. Previous research in this area has concentrated on single-landed slippers and leakage rates from such slippers have been examined, however only under static conditions. The work in this thesis is the first to consolidate experimental studies on multiple-land slippers, and the first to measure slipper leakage under dynamic conditions. These results have been compared with both CFD simulations and a new theoretical study undertaken in parallel with this work. The new test apparatus allowed measurement of both leakage and groove pressure under a range of operating conditions. It was established that the presence of a groove reduces the restoring moment produced, and hence enables the slipper to operate with an appropriate angle of tilt, thus permitting hydrodynamic lift to more readily exist. However, this occurs at a cost of increased leakage. In addition to the experimental work on slippers, the time-varying pressures within selected cylinders of an axial piston pump were measured. In parallel, a fully dynamic CFD model of a pump was produced. This model included all leakage paths from the pump. It was discovered that the port plate leakage dominated the overall leakage, with slipper leakage still being significant, but with piston leakage insignificant. This model was also used to predict the flow and pressure ripple from the pump and the predictions were compared with experimental measurements.

APA, Harvard, Vancouver, ISO, and other styles

15

Raymundo, F., G. Quispe, and C. Raymundo-Ibañeez. "Heavy Object Lifting Platform to Correct Human Balance and Posture." IOP Publishing Ltd, 2019. http://hdl.handle.net/10757/656295.

Full text

Abstract:

This research document on technological development is aimed at workers in small companies, those that are developing well and soon to emerge as companies that will be positioned at the top of their labor sector. Starting from the problem at present with respect to the bad manipulation of loads it is arranged to solve the problem with established objectives to try to correct the corporal posture at the time of lifting an object with a machine that replaces the functions of the worker. The design and the solution was made based on the requirements of the worker, workers who have the need to load objects at a certain height, here the man-machine relationship, demands and desires that help to achieve the general objective are analyzed. In addition, it has the main function of this machine: To lift heavy objects of up to 150 kg of mass, this due to the implementation of a hydraulic piston in the lifting platform. The appropriate solution is an adaptation of a platform in the form of a truck forming an angle of 47.17 between the structure of the truck and the horizontal surface, this position is the most adequate so that the back does not suffer injuries during the handling of loads at work. The results give assurance that it is a machine of reliability and easy handling since it only requires an operator to control the objects and a flat position on the back without damaging the spine.

APA, Harvard, Vancouver, ISO, and other styles

16

Goussard, Charl Leonard. "Design analysis of a lomolding machine." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019.1/1199.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Woolhead, Simon. "Piston control for an Integral Compression Wind Turbine." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29033/.

Full text

Abstract:

This thesis concerns an analysis of an Integral Compressed Air Wind Turbine (ICWT), in which energy is extracted from a slow-moving renewable source through the use of compressed air. This concept is particularly applicable to large offshore wind turbines, and can be readily integrated with compressed air energy storage methods. The ICWT has a very large rotor with free pistons travelling within the rotor blades, inducting and compressing air to high pressures at each end of the stroke. The compressed air can be stored and expanded when the energy is required, solving the intermittency issue of wind energy. By gathering energy along the rotor blades, rather than at the hub, it also avoids the very high torques associated with extremely large turbines. This thesis investigates optimal control strategies for ICWTs. Firstly, an initial model of the system using coupled ordinary differential equations (ODEs) is constructed to simulate a single piston pair of an ICWT system. This framework utilises several `modes' which the system passes through in the course of each stroke, with movement between modes controlled by simple algorithms. Calculations of potential and required energy are developed to allow basic control of the valve timings. The simulation is then extended to include thermal modelling of the walls of the compression tube, using orthonormal polynomials. A long-duration instance of the model is used to identify steady-state values for the orthonormal parameters, which demonstrates that the wall temperatures would remain within 15~K of the ambient temperature. One possible solution to the high temperatures caused by the near-adiabatic conditions of the compression is added to the model; namely, the injection of water droplets to the cylinder at the start of the compression stage. A method to efficiently simulate a phase transition in MATLAB is developed and implemented, allowing an analysis of the optimum mass balance of water to be injected to reduce the exhausted air temperature. An appendix examines several of the assumptions built into the model, in particular the rigidity of the components and variations in the rotational velocity of the rotor due to Coriolis and gravitational forces. Two valve control schemes are developed and implemented into the model; firstly, a simple proportional and derivative controller, which acts according to a rule dictating a gradual reduction in the energy surplus. This option proves to be limited in the degree to which it can avoid wasting compressed air. A second scheme, involving a simple version of sliding-mode control with two controllers operating at different timescales, is instead developed and shown to be significantly more effective at improving the system efficiency. Finally, an optimisation study is carried out on the `kick' stage, in which stored compressed air is used to accelerate the piston before compression. A large dataset of simulations allows for the specification of a set of optimum parameters based on a balance between power extraction from the rotating frame and net power generation.

APA, Harvard, Vancouver, ISO, and other styles

18

McAndrew, Ian Robert. "Predicting the principal failure modes of compression piston rings during assembly." Thesis, University of Hertfordshire, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302246.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Kim, Taeho, and Monika Ivantysynova. "Active Vibration Control of Axial Piston Machine using Higher Harmonic Least Mean Square Control of Swash Plate." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199412.

Full text

Abstract:

Noise emission is a major drawback of the positive displacement machine. The noise source can be divided into structure borne noise source (SBNS) and fluid borne noise source (FBNS). Passive techniques such as valve plate optimization have been used for noise reduction of axial piston machines. However, passive techniques are only effective for limited operating conditions or at least need compromises in design. In this paper, active vibration control of swash plate is investigated for vibration and noise reduction over a wide range of operating conditions as an additional method to passive noise reduction techniques. A 75cc pump has been modified for implementation of active vibration control using the swash plate. One tri-axial acceleration sensor and one angle sensor are installed on the swash plate and a high speed servovalve is used for the swash plate actuation. The multi-frequency two-weight least mean square (LMS) filter synthesizes the servovalve input signal to generate a destructive interference force which minimizes the swash plate vibration. An experimental test setup has been realized using Labview field-programmable gate array (FPGA) via cRIO. Simulation and experimental studies are conducted to investigate the possibility of active vibration control.

APA, Harvard, Vancouver, ISO, and other styles

20

Geffroy, Stefan, Niklas Bauer, Tobias Mielke, Stephan Wegner, Stefan Gels, Hubertus Murrenhoff, and Katharina Schmitz. "Optimization of the tribological contact of valve plate and cylinder block within axial piston machines." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71109.

Full text

Abstract:

In this paper, a simulation study is carried out for the development of concepts to optimize the tribological contact of valve plate and cylinder block in an axial piston machine in swash plate design. The valve plate/cylinder block contact is one of the three essential tribological contacts in axial piston machines. In a research project at the Institute for Fluid Power Drives and Systems (ifas), this contact is investigated by a specifically designed simulation tool. In addition, a test rig exists for the experimental investigation. With the results of simulation and experiment, it was shown before that the cylinder block is tilting to the high pressure side. Due to this movement, the gap height is not constant. In the area of minimum gap height, not only the fluid friction, but also the danger of solid body friction increases. Because of the higher friction losses in the area of minimum gap height, the temperature increase reduces the lifetime of the leaded coatings. In this paper, the results of the measurements as well as the simulation model are briefly summarized. It is followed by a simulation study of different possibilities to raise the gap height. Based on this pre-study, a first concept for the optimization of the tribological contact valve plate/cylinder block is presented and its applicability is discussed.

APA, Harvard, Vancouver, ISO, and other styles

21

Cosic, Alija. "Analysis of a novel Transversal Flux Machine with a tubular cross-section for Free Piston Energy Converter application." Doctoral thesis, KTH, Elektriska maskiner och effektelektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25834.

Full text

Abstract:

Constantly growing need for oil, all over the world, has caused oil price to rise rapidly during the last decade. High oil prices have made fuel economy as one of the most important factors when consumers are buying their cars today. Realizing this, many car manufacturers have developed or are looking for some alternative solutions in order to decrease fuel consumption. Combining two different technologies in a vehicle, the so called hybrid vehicle, can be seen as the first step toward a better and more sustainable development. There are several different solutions for hybrid vehicles today, among the best known are the Serie Electric Hybrid Vehicle (SEHV), the Parallel Electric Hybrid Vehicle (PEHV) and the Serie-Parallel Hybrid Electric Vehicle (SPEHV). By integrating a combustion engine with a linear electric machine into one unit, a system that is called Free Piston Energy Converter (FPEC) is achieved. The FPEC is suitable for use in a SEHV. Other application areas like stand alone generator are also possible. In this report a novel Transverse Flux Machine (TFM) with a tubular cross section of the translator has been investigated. Application of the machine in a FPEC has put tough requirement on the translator weight, specific power and force density. Different configurations of the winding arrangements as well as the magne tarrangement have been investigated. It has been concluded that the buried magnet design suffers from high leakage flux and is thus not asuitable TFM concept. Instead the surface mounted magnet design has been chosen for further investigation. An analytical model has been developed and a prototype machine has been built based on the analytical results. In order to have a better understanding of the machine characteristic a 3D-FEM analysis has been performed. The results from the analytical model, FEM model and measurements are analyzed and compared. The comparison between the measured and FEM-simulated results shows very good agreement. Furthermore, the results from the analytical model indicates that it can be successfully developed for further analysis and optimization of the design to give a cost-effective solution of the novel generato for mass production.
Det ständigt växande behovet av oljan runt om i världen, har fått oljepriset att stiga snabbt under det senaste decenniet. Detta har gjort bränsleekonomin till en av de viktigaste faktorer när konsumenterna väljer sina bilar i dag. Många biltillverkare har därför utvecklat eller söker efter alternativa lösningar till dagens förbränningsmotorer i hopp om att minska bränsleförbrukningen. Ett hybridfordon, ett fordon som är försedd med fler än en energiomvandlare, kan ses som ett första steg mot en bättre och mer hållbar utveckling. Det finns flera olika lösningar för hybridfordon i dag, bland de mest kända är Seriehybrid, Parallellhybrid och Serie-Parallelhybridfordon. Genom att integrera en förbränningsmotor med en linjär elektriskmaskin, erhålls ett system som kallas Frikolvsenergiomvandlare. Dennna typ av energiomvandlare lämpar sig bäst för användning i en seriehybridfordon, men andra användningsområden som fristående generator är också möjliga. I denna avhandling har en ny typ av Transversalflödesmaskin (TFM) med en cirkulärt tvärsnitt undersökts. Tillämpningen av maskinen i en Frikolvsenergiomvandlare har medfört tuffa krav på translatorvikten, specifikeffekten och kraftdensiteten. Olika lindnings- och magnetkonfiguratationer har undersökts. Forskningen har visat att designen med begravdamagneter lider av stort läckflöde och är därför inte lämplig för det nya TFM koncept. Istället har designen med ytmonterade magneter valts för vidare undersökning. En analytisk modell har utvecklats och en prototyp maskin har byggts med utgångspunkt i analysresultaten. För att få en bättre förståelse avmaskinkarakteristiken har en 3D-FEM modell tagits fram och analyserats. Resultaten från den analytiska modellen, FEM modellen och mätningar har analyserats och jämförts. Överensstämmelsen mellan de simulerade och de uppmätta resultaten är mycket bra. Dessutom, resultaten från den analytiska modellen visar på att modellen kan framgångsrikt användas för fortsatt analys och optimering av maskinen för att ge en kostnadseffektivlösning för masstillverkning.
QC 20101102

APA, Harvard, Vancouver, ISO, and other styles

22

Chomier, Mickael Thierry. "Effect of Vortex Roll-up and Crevice Mass Flow on Ignition in a Rapid Compression Machine." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1374666527.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

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

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

24

Mukherjee, Swarnava, Lizhi Shang, and Andrea Vacca. "A fast approach for coupled fluid-thermal modeling of the lubricating interfaces of axial piston machines." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71103.

Full text

Abstract:

The temperature distribution of the lubricating interfaces is an important aspect of the functioning of positive displacement machines. It can determine the efficiency and the life time of the unit. In particular, it directly affects the fluid properties and the thermal induced deformations of the solid bodies. A simulation tool capable of predicting the fluid temperature in such gaps thus becomes very useful in the design process of these machines. The temperature distribution in a film comprises of many physical phenomena including convection and conduction along and across the film. Past numerical approaches solved this multi-directional conduction-convection problem using a threedimensional(3D) grid, making the tool computationally expensive and unsuitable for fast simulations. This paper proposes a hybrid fluid temperature solver, based on, a low computational cost twodimensional(2D) grid, to reduce the simulation time with reasonable accuracy. The piston/cylinder interface of an axial piston machine is selected as reference case to demonstrate the proposed approach. The hybrid approach was found to speedup the simulation times by 36%.

APA, Harvard, Vancouver, ISO, and other styles

25

Islam, Md Rezaul. "A floating liner facility and studies of friction at a reciprocating piston-cylinder wall interface." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/35653/.

Full text

Abstract:

The piston-cylinder liner interface comprises more than half of the total engine rubbing friction. With current demand being for internal combustion engines with better fuel economy, lower exhaust emissions and higher performance, reducing this form of friction is the subject of much study. The research reported in this thesis is concerned with the development of an existing floating liner rig to measure the friction in this region. The performance features of the modified setup have also been assessed. Parametric studies have been undertaken with the modified setup to identify the potential means of friction reduction. Modifications undertaken in the sealing method and driveline assembly has facilitated friction measurement at higher gas loading of up to 80 barg. The modified sealing assembly with a sealing ring overcame the problem of arbitrary force interruption through irregular liner and seal contacts. Addition of five times higher inertia flywheel aided the motor to support the rig with adequate torque during high gas loading operations. Calibrations have been performed at each different build of piston-liner combination to reduce build to build variability in measurement. Experimental studies have been undertaken to assess the friction characteristics for different factors such as operating pressure, temperature and speed, lubricant oil formulation, piston-liner clearance, piston material etc. Tests have been undertaken at a range of operating conditions; peak pressure of 0 to 80 barg, speed of 1000 to 2000 rpm and average mid-liner temperature of 40 to 90 ˚C. Peak cylinder pressure has been observed to be dominating the friction followed by temperature and speed. Friction spikes were observed near the top dead centre for pressurised operations; where normal load on the rings are highest in a cycle. Higher speed generally results in a higher total frictional loss. However at higher temperature and peak pressure, contrasting effect of speed on total friction has been reported. The study further identified that piston motion play important roles in determining mixed/boundary friction along with the local gas pressure, velocity and oil film temperature. Friction reductions have been obtained by using a lower viscosity oil and higher piston-liner clearance. Maximum friction reduction of 18% has been reported in this study by using SAE 0W-30 oil in place of SAE 5W-30. Diametric clearance of 80 μm obtained a maximum reduction of 12% compared to a lower clearance of 20 μm. The use of steel piston has shown potential in reducing friction over aluminium piston but the design and weight of piston played a dominant role in the frictional loss.

APA, Harvard, Vancouver, ISO, and other styles

26

Wegner, Stephan [Verfasser]. "Experimental and Simulative Investigation of the Cylinder Block/Valve Plate Contact in Axial Piston Machines / Stephan Wegner." Düren : Shaker, 2021. http://d-nb.info/1233548484/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Samuel, Kärnell. "An Experimental Analysis of Valve Plate Control : a New Approach to Displacement Control for Hydraulic Piston Machines." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-142373.

Full text

Abstract:

Displacement control of a pump means controlling the amount of fluid that is pumped per rotation. This is used to increase the efficiency or controlling the flow in a system and currently there is almost exclusively one type of displacement control available for piston machines on the market. With this method, the stroke length of the pistons can be varied by changing the angle of the so-called swashplate. There are however drawbacks with this principle that mainly concern in stability or efficiency. In this thesis, an unconventional approach to displacement control has been experimentally evaluated. The principle of this method is to vary the effective use of the stroke length by rotating the valve plate, which is a component that separates the inlet from the outlet. This can be done with an electric motor and the problems concerning efficiency and stability can be avoided. The main drawback with this type of control is however the high noise level caused by pressure ripple in the cylinders. This thesis treats the characteristics of this type of control, both theoretically and experimentally, and describes the analysed prototype. It also deals with new conceptual designs for this type of control. How-ever, in summary it can be said that the prototype behaved as expected but had problems with leakage.

APA, Harvard, Vancouver, ISO, and other styles

28

Mehta, Viral. "Torque ripple attenuation for an axial piston swash plate type hydrostatic pump noise considerations /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4380.

Full text

Abstract:

Thesis (Ph.D.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 28, 2007). Vita. Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

29

Chacon, Rene, and Monika Ivantysynova. "An Investigation of the Impact of the Elastic Deformation of the End case/Housing on Axial Piston Machines Cylinder Block/Valve Plate Lubricating Interface." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199578.

Full text

Abstract:

The cylinder block/valve plate interface is a critical design element of axial piston machines. In the past, extensive work has been done at Maha Fluid Power Research center to model this interface were a novel fluid structure thermal interaction model was developed which accounts for thermal and elasto-hydrodynamic effects and has been proven to give an accurate prediction of the fluid film thickness. This paper presents an in-depth investigation of the impact of the elastic deformation due to pressure and thermal loadings of the end case/housing on the performance of the cylinder block/valve plate interface. This research seeks to understand in a systematic manner the sensitivity of the cylinder block/valve plate interface to the structural design and material properties. A comparison between simulations results is done by utilizing different end case designs and material compositions, both in the valveplate and end case solids.

APA, Harvard, Vancouver, ISO, and other styles

30

Alqahtani, Ali Mubark. "Computational studies of homogeneous charge compression ignition, spark ignition and opposed piston single cylinder engines." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7899/.

Full text

Abstract:

In this research, possible improvements in engine specifications using the simulations developed on the AVL BOOST™ and Ricardo WAVE™ platforms were investigated. These modelling simulations help the author to predict the effect of any improvements in engine specifications without practical experimental challenges and difficulties. Firstly, HCCI and SI engines were modelled with the intention of maximizing the engine’s efficiency and minimizing the emissions. Changes of valve timing and throttle angle influence emissions’ reduction and the efficiency of the engine. In SI engines, the emissions of NOx can be reduced by using EGR, while only having a little effect on performance. The emissions from the HCCI, due to their intrinsically low emission output, were not improved. The effect of increasing the bore to stroke ratio in an opposed piston engine whilst maintaining a constant swept volume, port geometry and combustion timing, shows an increase of heat losses due to the lower ratio of exposed surface area to volume; an increase in thermal and mechanical efficiency; and most importantly, an improvement in fuel consumption. Also, in this research study, different strategies for opposed piston engines were investigated to increase the engine’s efficiency. The effect of a variable compression ratio on an opposed piston engine’s performance indicates different behaviour at various engine speeds and under different running conditions.

APA, Harvard, Vancouver, ISO, and other styles

31

Wegner, Stephan Verfasser], Hubertus [Akademischer Betreuer] [Murrenhoff, and Katharina [Akademischer Betreuer] Schmitz. "Experimental and simulative investigation of the cylinder block/valve plate contact in axial piston machines / Stephan Wegner ; Hubertus Murrenhoff, Katharina Schmitz." Aachen : Universitätsbibliothek der RWTH Aachen, 2021. http://d-nb.info/1234349183/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Wegner, Stephan, Fabian Löschner, Stefan Gels, and Hubertus Murrenhoff. "Validation of the physical effect implementation in a simulation model for the cylinder block/valve plate contact supported by experimental investigations." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199564.

Full text

Abstract:

Overall losses in swash plate type axial piston machines are mainly defined by three tribological interfaces. These are swash plate/slipper, piston/cylinder and cylinder block/valve plate. Within a research project, funded by the German Research Foundation, a combined approach of experimental research and simulation is chosen to acquire further knowledge on the cylinder block/valve plate contact. The experimental investigations focus on the friction torque within the contact and the measurement of the cylinder block movement in all six degrees of freedom. Simultaneously a simulation model is created focusing on the main physical effects. By considering the results of the experimental investigations significant physical effects for the simulation model are assessed. Within this paper a first comparison between experimental results and the simulation is presented, showing that for a qualitative match the implemented effects (mainly the fluid film, solid body movement, solid body contact, surface deformation) are sufficient to model the general behaviour of theinvestigated pump.

APA, Harvard, Vancouver, ISO, and other styles

33

Hacioglu, Bilgin. "Investigation Of The Effect Of Oil Groove In The Performance Of A Compressor Piston." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12608024/index.pdf.

Full text

Abstract:

Oil feed grooves are implemented in reciprocating compressor piston applications to assure a constant supply of lubricating oil on bearing surfaces and decrease friction loss. In a hermetically sealed compressor, due to small clearances encountered, oil supply becomes critical in order not to operate in boundary lubrication regime. Due to the small size of the piston and small piston &ndash
cylinder clearance, a partial lubrication regime is present. In the current study, a model that solves Reynolds&rsquo
equation for piston-cylinder lubrication and the average Reynolds&rsquo
equation that considers the effect of roughness on partially lubricated bearing for a compressor piston with oil feed grooves is developed. A parametric study is carried out to investigate the effects of piston design parameters and then arrive at an improved piston performance by using alternative designs for oil feed groove and the other design parameters.

APA, Harvard, Vancouver, ISO, and other styles

34

SILVA, Francisca Cibele da. "Estudo termográfico de auxílio ao diagnóstico de falhas mecânicas em pistas de rolamento: o caso dos rolamentos rígidos de uma carreira de esferas sem blindagem." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1181.

Full text

Abstract:

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-16T14:51:43Z No. of bitstreams: 1 FRANCISCA CIBELE DA SILVA - DISSERTAÇÃO (PPGEM) 2016.pdf: 4026542 bytes, checksum: ed454ebfc1325519e82b94fd3c4aab3e (MD5)
Made available in DSpace on 2018-07-16T14:51:43Z (GMT). No. of bitstreams: 1 FRANCISCA CIBELE DA SILVA - DISSERTAÇÃO (PPGEM) 2016.pdf: 4026542 bytes, checksum: ed454ebfc1325519e82b94fd3c4aab3e (MD5) Previous issue date: 2016-08-31
Capes
O objetivo deste trabalho foi estudar falhas mecânicas em elementos de máquina por meio da Termografia. O caso pesquisado foi o dos rolamentos rígidos de uma carreira de esferas sem blindagem. Quanto aos objetivos a pesquisa é explicativa e quanto aos procedimentos técnicos é de carácter experimental. A metodologia utilizada, neste trabalho, fez uso de uma bancada de teste constituída por motor, rolamento e mancal, montada em mesa inercial, monitorada por meio de sensores de vibração e câmera térmica. Nas amostras de rolamentos foram inseridas falhas mecânicas por meio de uma micro retífica e sob condições de controle de rotação, carga, temperaturas, ventilação e umidade foram realizados os testes. Como resultado pôde-se perceber alterações térmicas em determinadas regiões dos rolamentos, as quais coincidiram com picos de frequência oscilatória do espectro de vibração em função do tempo da FFT. Outro aspecto importante é que as detecções térmicas são melhor evidenciadas nos primeiros minutos de acionamento do sistema observado. Como conclusão pode-se afirmar que é possível utilizar a técnica da Termografia para detectar falhas mecânicas em rolamentos desde que a análise termográfica seja realizada nos instantes iniciais de aquecimento do objeto, com atenção para se manter as condições ambientais e demais variáveis de estudo sob controle.
The objective of this work was to study mechanical failures in machine elements through Thermography. The case investigated was that of the rigid bearings of a sphere race without shielding. Regarding the objectives, the research is explanatory and technical procedures are experimental. The methodology used, in this work, made use of a test bench constituted by motor, bearing and bearing, mounted in inertial table, monitored by means of vibration sensors and thermal camera. In the samples of bearings mechanical faults were inserted through a micro grinding and under conditions of control of rotation, load, temperatures, ventilation and humidity were carried out the tests. As a result, it was possible to observe thermal changes in certain regions of the bearings, which coincided with oscillatory frequency peaks of the vibration spectrum as a function of FFT time. Another important aspect is that the thermal detections are better evidenced in the first few minutes of the observed system activation. It can be concluded that it is possible to use the Thermography technique to detect mechanical failures in bearings as long as thermographic analysis is performed in the initial instants of heating the object, with attention to maintain the environmental conditions and other variables of study under control.

APA, Harvard, Vancouver, ISO, and other styles

35

Maurice, Franck. "Intégration et mise en oeuvre de plans d’expériences numériques en modélisation et simulation système : étude de cas en ingénierie et dimensionnement des composants hydrauliques de puissance." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2538.

Full text

Abstract:

Cette thèse s'inscrit dans le cadre d'une Convention Industrielle de Formation par la Recherche (CIFRE) issue du partenariat entre le laboratoire Roberval de l'Université de Technologie de Compiègne et l'entreprise HYDRO LEDUC. Cette dernière fabrique et conçoit des composants hydrauliques tels que des pompes et moteurs à pistons, des accumulateurs, des vérins, mais aussi des outils spécifiques destinés à des applications diverses et variées. La discipline de l'hydraulique de puissance est omniprésente dans de nombreuses applications industrielle. Elle constitue une solution incontournable pour toutes les utilisations qui nécessitent des puissances élevées. Elle touche ainsi de nombreux domaines d'activité tels que les transports, l'aéronautique, les machines-outils, le BTP et bien d'autres. Les circuits hydrauliques, que ce soit en termes d'entrainement ou de contrôle, présentent de nombreux avantages. IIS permettent entre autre de transmettre des efforts considérables, garantissent un contrôle précis des récepteurs qu'ils soient linéaires ou rotatifs, et ont une durée de vie élevée. Les pompes hydrauliques sont le véritable cœur de tous les circuits hydrauliques. Dotées d'une puissance massique inégalable, elles sont capables de travailler à des hautes pressions tout en conservant un haut rendement global. Les contraintes environnementales ainsi que l'augmentation du prix de l'énergie font croître la demande en composants toujours plus performants. Afin de rester compétitif, les fabricants sont contraints de répondre à ces exigences tout en contrôlant leurs coûts de développement et production. La méthode conventionnelle d'amélioration des produits basée sur des cycles essais/erreurs est une démarche financièrement coûteuse et chronophage. Les vingt dernières années ont vu la puissance de calcul des ordinateurs croître de manière exponentielle, faisant de la simulation numérique un véritable outil de compréhension des phénomènes physiques et d'amélioration des produits. L'enjeu de notre travail consiste à s'approprier et à analyser les multiples données et savoirs théoriques issues de nombreuses années de travaux de recherche. A partir de ce socle de connaissances, l'objectif est de mettre au point une méthode de conception mettant en oeuvre la démarche des plans d'expériences et reposant sur la modélisation ainsi que sur la simulation dans la conception intégrée de composants hydrauliques. Cette dernière a été appliquée à une pompe à pistons axiaux à cylindrée variable. En effet, associée à des stratégies de conception dûment établies, la simulation numérique permet de réduire considérablement les temps de développement et d'amélioration des produits tout en diminuant de manière drastique le nombre d'essais expérimentaux
This thesis has been achieved as part of the partnership between HYDRO LEDUC company and Roberval laboratory located at the "Université de Technologie de Compiègne". HYDRO LEDUC designs and makes hydraulic components such as piston pumps and motors, accumulators, cylinders and specific tools reserved for varied applications. A large amount of applications uses fluid power transmission. Indeed, because of its high power density, hydraulic solutions are unavoidable. Thus, this latter is present in various fields such as transport, aeronautical, machine tool, building industry and many others. Hydraulic circuits allow delivering considerable efforts. They enable a very accurate control of receptors and ensure a high life time to systems and components. Hydraulic pumps can be considered as the heart of every hydraulic systems. Their matchless high power density makes them to perform at high pressure while keeping a high efficiency level. Environment constraints, energy cost rise and global market have led manufacturers to make products more efficient while decreasing their manufacturing and development costs. Conventional design methodology relies on test/error cycles, which is a development strategy that can be expensive and time consuming. Computing power of computers have been increasing sharply over the last 20 years. In that sense, numerical simulation has become the mainstream in terms of design, research and development and physical analysis. The objective of our work is to gather, and analyse data and theoretical knowledge stem from many years of research investigations. From this point, the second goal of our work is to choose and develop a design strategy, which employs Design of Experiments method, and relying on numerical modelling and simulation applied to hydraulic components. This latter has been applied to a variable displacement axial piston pump. Hence, performing a design strategy that integrates Design of Experiments, numerical simulation and modelling for hydraulic components leads to reduce considerably the time and the cost of the design process

APA, Harvard, Vancouver, ISO, and other styles

36

Labbé, Benjamin. "Machines à noyaux pour le filtrage d'alarmes : application à la discrimination multiclasse en environnement maritime." Thesis, Rouen, INSA, 2011. http://www.theses.fr/2011ISAM0002.

Full text

Abstract:

Les systèmes infrarouges sont essentiels pour fournir aux forces armées une capacité de reconnaissance des menaces. En contexte opérationnel, ces systèmes sont contraints au temps-réel et à l’accès à des taux de fausses alarmes faibles. Ceci implique la détection des menaces parmi de nombreux objets non-pertinents.Dans ce document, nous combinons des OneClass-SVM pour une décision multiclasse avec rejet(préservant la fausse-alarme). En apprentissage, nous sélectionnons les variables pour contrôler la parcimonie du moteur de décision.Nous présentons également un classifieur original, le Discriminative OneClass-SVM, combinant les propriétés du C-SVM et du OneClass-SVM dans le contexte multiclasse. Ce détecteur de nouveauté n’a pas de dépendance au nombre de classes. Ceci permet une utilisation sur des données à grande échelle.Nos expériences sur des données réelles démontrent l’intérêt des propositions pour les systèmes fortement contraints, face aux méthodes de référence
Infrared systems are keys to provide automatic control of threats to military forces. Such operational systems are constrained to real-time processing and high efficiency (low false-alarm rate) implying the recognition of threats among numerous irrelevant objects.In this document, we combine OneClass Support Vector Machines (SVM) to discriminate in the multiclass framework and to reject unknown objects (preserving the false-alarm rate).While learning, we perform variable selection to control the sparsity of the decision functions. We also introduce a new classifier, the Discriminative OneClass-SVM. It combines properties of both the biclass-SVM and the OneClass-SVM in a multiclass framework. This classifier detects novelty and has no dependency to the amount of categories, allowing to tackle large scale problems. Numerical experiments, on real world infrared datasets, demonstrate the relevance of our proposals for highly constrained systems, when compared to standard methods

APA, Harvard, Vancouver, ISO, and other styles

37

Abuhaiba, Mohammad. "Mathematical Modeling and Analysis of a Variable Displacement Hydraulic Bent Axis Pump Linked to High Pressure and Low Pressure Accumulators." Connect to full text in OhioLINK ETD Center, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1240528916.

Full text

Abstract:

Dissertation (Ph.D.)--University of Toledo, 2009.
Typescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy degree in Mechanical Engineering." Bibliography: leaves 203-209.

APA, Harvard, Vancouver, ISO, and other styles

38

Blust, Markus [Verfasser], and A. [Akademischer Betreuer] Albers. "Effizientes Screening des tribologischen Eignungspotenzials alternativer Werkstoffpaarungen für den Einsatz in tribologischen Kontakten von Axialkolbenmaschinen als Beitrag zum Produktentstehungsprozess = Efficient screening of the tribological suitability potential of alternative material combinations for the usw in tribological contacts of axial piston machines as a contribution to the product development process / Markus Blust ; Betreuer: A. Albers." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/123406376X/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Castaings, Thibaut. "Catalogage de petits débris spatiaux en orbite basse par observations radars isolées." Phd thesis, Grenoble, 2014. http://tel.archives-ouvertes.fr/tel-00955486.

Full text

Abstract:

Les débris spatiaux sont devenus une menace considérable pour la viabilité des satellites opérationnels en orbite basse. Afin de pouvoir éviter des collisions accidentelles, des systèmes de surveillance de l'espace existent mais sont limités en performances de détection pour les objets de petite taille (diamètre inférieur à 10cm), ce qui pousse à l'étude de nouvelles solutions. Cette thèse a pour objectif d'appuyer la faisabilité d'un système radar au sol utilisant un champ de veille étroit pour le catalogage de petits débris en orbite basse. Un tel système fournirait en effet des observations dites " isolées ", c'est-à-dire qu'une orbite n'est pas immédiatement déductible de chacune d'entre elles. Le grand nombre combinaisons nécessaires est alors prohibitif en termes de temps de calcul pour la résolution de ce problème de pistage. Nous proposons dans ces travaux une nouvelle méthode pour initialiser les pistes, c'est-à-dire associer des observations isolées avec une faible ambiguïté et en déduire des orbites précises. Les pistes ainsi obtenues sont combinées et filtrées grâce à un algorithme de pistage multicible que nous avons adapté aux particularités du problème. Avec un taux de couverture de plus de 80% obtenu en temps réel sur 3 jours pour des scénarios de 500 à 800 objets en plus d'un fort taux de fausses alarmes, les performances de la méthode proposée tendent à prouver la faisabilité du système envisagé. Afin d'extrapoler les résultats obtenus à de plus fortes densités d'observations, nous proposons un modèle de complexité combinatoire calibré sur les performances de l'algorithme aux faibles densités. L'apport d'un second capteur identique est également étudié et met en évidence un point de compromis entre réactivité et complexité combinatoire, ce qui offre un degré de liberté supplémentaire dans la conception d'un tel système.

APA, Harvard, Vancouver, ISO, and other styles

40

Wu, Chih-Ting, and 伍智廷. "Optimal Design of Piston Pump of Airless Spraying Machine." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/27254670536977328520.

Full text

Abstract:

碩士
國立高雄應用科技大學
機械與精密工程研究所
104
The objective of this study is to investigate performance of the piston flow control of airless sprayer. A commercial software, Solidworks, is used to create the piston pump airless sprayer model, and COMSOL Multiphysics software used to pump airless sprayer model analysis of fluid-solid coupling , obtaining the variation of flowrate at a given volume flow changes of the inlet and outlet. Also the theory is used to verify its accuracy. The analysis of various materials ball effect was also conducted. The results show that the analysis simulation model of this study can improve the performance of holding pressure effect of the piston pump airless sprayer from about 3% to 6%, it also can improve the daily facilities amount of 20% to 30%.

APA, Harvard, Vancouver, ISO, and other styles

41

(10135868), Meike H. Ernst. "Enabling High-Pressure Operation with Water for the Piston-Cylinder Interface In Axial Piston Machines." Thesis, 2021.

Find full text

Abstract:

Water is inflammable, non-toxic, environmentally friendly--- desirable traits, for a hydraulic fluid. However, its extremely low viscosity diminishes the load-bearing and sealing capacity of lubricating interfaces. Case in point: axial piston machines of swash plate design are compact, highly efficient positive displacement machines at the heart of hydraulic systems in forestry, construction, aerospace, and agricultural equipment, as well as industrial applications (presses, etc.); however, the three main lubricating interfaces decisive to the performance of such units in terms of both component life and efficiency are challenged by the use of water as working fluid. Especially during high-pressure operation, this low-viscosity lubricant can cause the these interfaces to fail in carrying the imposed load, resulting in severe wear, or even pump failure. The piston-cylinder interface is particularly challenging to design for water because it stands under obligation to carry the heavy side load that acts on the pistons of these machines, which increases with operating pressure. Furthermore, the architecture of axial piston machines of swash plate design does not allow this interface to be hydrostatically balanced.

Through the development of a methodology that separates the fluid pressure fields of the three main lubricating interfaces of axial piston machines into their hydrostatic and hydrodynamic components, the present work enables a direct comparison of these interfaces in terms of how they support load. A case study of a 75 cc unit running on hydraulic oil conducted via this methodology at three different operating conditions (low pressure/low speed, low pressure/high speed, and high pressure/low speed) demonstrates that in the piston-cylinder interface, the force from hydrostatic pressure reaches such high magnitudes over the high-pressure stroke that less than half of it is needed to counter the load. The excess force from hydrostatic pressure then becomes the load. Consequentially, hydrodynamic pressure must counter a force from hydrostatic pressure that exceeds the original load. In the other two interfaces, by contrast, over half the load is being carried by hydrostatic pressure, thus significantly diminishing the amount of hydrodynamic pressure the interfaces are required to generate in order to achieve full load support. Moreover, nearly all of the moment on the piston is countered by hydrodynamic pressure, while less than half of the moment on the block is countered by hydrodynamic pressure, and the moment on the slipper is negligible by comparison.

While this case study only investigates one pump, it shows how critical hydrodynamic pressure can be to load support in the piston-cylinder interface. The use of a low-viscosity fluid, e.g. water, reduces the hydrodynamic pressure that is generated in this interface, which, at challenging operating conditions, can lead to metal-to-metal contact. However, the performance of the interface can be improved via micro surface shaping, i.e. by giving the surface of the piston, or the bore that it moves through, a shape on the order of microns in height. The aim of present work is to pursue design trends leading to surface shapes that will enable this interface to function at higher pressures than currently achievable.

This pursuit takes the form of systematic virtual design studies, an optimization procedure, and an algorithm developed specifically for tailoring the bore surfaces through which the pistons travel to piston tilt and deformation. From this emerges not only a set of design trends corresponding to the dimensions of two particularly powerful types of micro surface shaping, but also a profound insight into the behavior of the water-lubricated piston-cylinder interface fluid film, and how that behavior can be manipulated by changing the component surfaces that constitute its borders. Furthermore, in collaboration with Danfoss High Pressure Pumps, a physical prototype of a 444 cc axial piston pump with surface shaping generated via the aforementioned algorithm has been constructed and tested, achieving a total pump efficiency roughly 3% higher than that achievable by the commercial unit that the geometry of the prototype is based on.

APA, Harvard, Vancouver, ISO, and other styles

42

(5929562), Rene Chacon Portillo. "VIRTUAL PROTOTYPING OF AXIAL PISTON MACHINES OF SWASH PLATE TYPE." Thesis, 2019.

Find full text

Abstract:

Axial piston machines are widely used in the industry ranging from aerospace, agriculture, automotive, heavy machinery, etc. These applications require better pumps and motors to meet current market demands such as higher power density in hydraulic units, smarter pumps (diagnostics and prognostics), higher efficiencies, and compactness. The current state-of-the-art in pump design is mostly based on heuristic design approach with very limited use of numerical toolssince the invention of this positive displacement machine until the present time. The numerical tools being used do not capture the physical phenomena in the thin fluid film between the rotating group components. The work presented in this dissertation aims to demonstrate the feasibility of virtual prototyping utilizing a combination of in-house developed multi-domain models and to propose a novel computational based design methodology for axial piston machines. The methodology is an iterative process between the virtual components in 3D CAD models and the function evaluations for the design requirements utilizing the numerical models which provide an accurate prediction to the behavior of the mechanical components working together. To validate the proposed methodology a case study on a 24 cc/rev axial piston machine was carried out. The machine was built virtually, simulated,and optimized for desired performance. A physical prototype was built based on the case study and tested successfullyfor forty-five operating conditions.

APA, Harvard, Vancouver, ISO, and other styles

43

(5930255), Lizhi Shang. "A Path Toward an Effective Scaling Approach for Axial Piston Machines." Thesis, 2019.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

44

(5930537), Abhimanyu Baruah. "VALVE PLATE DESIGN MODEL FOCUSING ON NOISE REDUCTION IN AXIAL PISTON MACHINES." Thesis, 2019.

Find full text

Abstract:

The advantages of high efficiency, reliability, flexibility and high power to weight ratio make axial piston pumps popular for use in a wide variety of applications like construction and agricultural machinery, off road vehicles and aerospace applications. However, a major drawback which limits their extensive use in other commercial applications is noise. One of the important components in axial piston machines is the valve plate, which influences the transition of the suction and delivery flows into and out of the displacement chamber. Appropriate design of the valve plate can play a significant role in influencing the rate of compression and expansion in the displacement chamber, and hence contribute towards the abatement of noise in axial piston machines. Furthermore, the relief grooves in valve plates makes them relatively less sensitive to operating conditions for the operation of the pump. The high sensitivity of the valve plate design towards the pressure build up in the displacement chamber and towards the noise sources are big motivation factors towards rigorously exploring the design space to find suitable designs to meet the objective of noise reduction. This motivates the development of an advanced computational tool, colloquially called 'MiNoS', where a powerful optimization algorithm has been combined together with a novel parametrization scheme for valve plate design and a 1D simulation model of swash plate type axial piston machines to find optimized designs which can contribute towards noise reduction in swash plate type axial piston machines. Furthermore, incorporation of the appropriate constraint also helps in avoiding designs susceptible to the onset of cavitation in the displacement chamber. A case study performed using the developed computational tool has been shown later in this work.

APA, Harvard, Vancouver, ISO, and other styles

45

(8770307), Nathan J. Keller. "Condition Monitoring Systems for Axial Piston Pumps: Mobile Applications." Thesis, 2020.

Find full text

Abstract:

Condition monitoring of hydraulic systems has become more available and inexpensive to implement. However, much of the research on this topic has been done on stationary hydraulic systems without the jump to mobile machines. This lack of research on condition monitoring of hydraulic systems on mobile equipment is addressed in this work. The objective of this work is to develop a novel process of implementing an affordable condition monitoring system for axial piston pumps on a mobile machine, a mini excavator in this work. The intent was to find a minimum number of sensors required to accurately predict a faulty pump. First, an expert understanding of the different components on an axial piston pump and how those components interact with one another was discussed. The valve plate was selected as a case study for condition monitoring because valve plates are a critical component that are known for a high percentage of failures in axial piston pumps. Several valve plates with various degrees of natural wear and artificially generated damage were obtained, and an optical profilometer was used to quantify the level of wear and damage. A stationary test-rig was developed to determine if the faulty pumps could be detected under a controlled environment, to test several different machine learning algorithms, and to perform a sensor reduction to find the minimum number of required sensors necessary to detect the faulty pumps. The results from this investigation showed that only the pump outlet pressure, drain pressure, speed, and displacement are sufficient to detect the faulty pump conditions, and the K-Nearest Neighbor (KNN) machine learning algorithms proved to be the least computationally expensive and most accurate algorithms that were investigated. Fault detectability accuracies of 100% were achievable. Next, instrumentation of a mini excavator was shown to begin the next phase of the research, which is to implement a similar process that was done on the stationary test-rig but on a mobile machine. Three duty cycle were developed for the excavator: controlled, digging, and different operator. The controlled duty cycle eliminated the need of an operator and the variability inherent in mobile machines. The digging cycle was a realistic cycle where an operator dug into a lose pile of soil. The different operator cycle is the same as the digging cycle but with another operator. The sensors found to be the most useful were the same as those determined on the stationary test-rig, and the best algorithm was the Fine KNN for both the controlled and digging cycles. The controlled cycle could see fault detectability accuracies of 100%, while the digging cycle only saw accuracies of 93.6%. Finally, a cross-compatibility between a model trained under one cycle and using data from another cycle as an input into the model. This study showed that a model trained under the controlled duty cycle does not give reliable and accurate fault detectability for data run in a digging cycle, below 60% accuracies. This work concluded by recommending a diagnostic function for mobile machines to perform a preprogrammed operation to reliably and accurately detect pump faults.

APA, Harvard, Vancouver, ISO, and other styles

46

(5930510), Ashkan Abbaszadeh Darbani. "EFFECTS OF SLIPPER SURFACE SHAPING AND SWASHPLATE VIBRATION ON SLIPPER-SWASHPLATE INTERFACE PERFORMANCE." Thesis, 2019.

Find full text

Abstract:

This thesis investigates the effects of swashplate vibration and slipper surface geometry on the performance of the slipper-swashplate interface. The lubricating interfaces within a swashplate type axial piston machine are the most complicated part of the design process. These interfaces are supposed to provide support to the significant loads they experience during operation and to prevent continuous contact of the sliding surfaces. Therefore a proper slipper-swashplate interface design ensures full film lubrication during operation and provides sufficient load support while minimizing viscous and volumetric losses at the same time. The effects of two factors on the performance of the slipper-swashplate are examined during this work; swashplate vibration and slipper surface micro-geometry. An already existing model of the slipper-swashplate interface was used to carry out the results for this work however some modifications were made to the model to suit the needs of this research. Swashplate vibration is a phenomenon that has not been implemented in the model before, therefore its effects on the performance of the interface were analyzed. Thickness of the fluid film in the lubricating regime corresponds with its performance and is directly affected by the micro-geometry of the sliding interfaces. Therefore the effects of slipper surface micro-geometry is crucial to study in order to find the optimal slipper-swashplate interface design.

APA, Harvard, Vancouver, ISO, and other styles

47

(9746363), Thomas Ransegnola. "A Strongly Coupled Simulation Model of Positive Displacement Machines for Design and Optimization." Thesis, 2020.

Find full text

Abstract:

Positive displacement machines are used in a wide variety of applications, ranging from fluid power where they act as a transmission of power, to lubrication and fluid transport. As the core of the fluid system responsible for mechanical--hydraulic energy conversion, the efficiencies of these units are a major driver of the total efficiency of the system. Furthermore, the durability of these units is a strong decider in the useful life of the system in which they operate.

The key challenge in designing these units comes from understanding their working principles and designing their lubricating interfaces, which must simultaneously perform a load carrying and sealing function as the unit operates. While most of the physical phenomena relevant to these machines have been studied previously in some capacity, the significance of their mutual interactions has not. For this reason, the importance of these mutual interactions is a fundamental question in these machines that this thesis answers for the first time. In analysis of two different machine types, it is confirmed that mutual interactions of both physical phenomena and neighboring fluid domains of the unit contribute significantly to the overall performance of the machine. Namely, these analyses demonstrate load sharing owing to mutual interactions on average of 20% and as high as 50%, and mutual flow interactions of at least 10%.

In this thesis, the behavior of the thin films of fluid in the lubricating interfaces of the units, the bodies that make up these films, and the volumes which interface with them will be considered. The resulting coupled problem requires a model that can consider the effects of motion of all floating bodies on all films and volumes, and collect the resulting loads applied by the fluid as it responds. This will require a novel 6 degree of freedom dynamics model including the inertia of the bodies and the transient pressure and shear loads of all interfaces of the body and the fluid domain.

During operation, fluid cavitation and aeration can occur in both the displacement chambers of the machine and its lubricating interfaces. To capture this, a novel cavitation algorithm is developed in this thesis, which considers the release of bubbles due to both gas trapped within the fluid and vaporization of the operating fluid in localized low pressure regions of the films. In the absence of cavitation, this model will also be used to find the pressures and flows over the film, communicating this information with the remainder of the fluid domain.

Due to the high pressures that form in these units, the bodies deform. The resulting deformation changes the shape of the films and therefore its pressure distribution. This coupled effect will be captured in one of two ways, the first relying on existing geometric information of the unit, and the other using a novel analytical approach that is developed to avoid this necessity. In either case, the added damping due to the shear of the materials will be considered for the first time. Additionally in regions of low gap height, mixed lubrication occurs and the effects of the surface asperities of the floating bodies cannot be neglected. Accurate modeling of this condition is necessary to predict wear that leads to failure in these units. This work will then develop a novel implementation for mixed lubrication modeling that is directly integrated into the cavitation modeling approach.

Finally, effort is made to maintain a generic tools, such that the model can be applied to any positive displacement machine. This thesis will present the first toolbox of its kind, which accounts for all the mentioned aspects in such a way that they can be captured for any machine. Using both multithreaded and sequential implementations, the tool will be capable of fully utilizing a machine on which it is run for both low latency (design) and high throughput (optimization) applications respectively. In order to make these applications feasible, the various modules of the tool will be strongly coupled using asynchronous time stepping. This approach is made possible with the development of a novel impedance tensor of the mixed universal Reynolds equation, and shows marked improvements in simulation time by requiring at most 50% of the simulation time of existing approaches.

In the present thesis, the developed tool will be validated using experimental data collected from 3 fundamentally different machines. Individual advancements of the tool will also be verified in isolation with comparison to the state of the art and commercial software in the relevant fields. As a demonstration of the use of the tool for design, detailed analysis of the displacing actions and lubricating interfaces of these same units will be performed. These validations demonstrate the ability of the tool to predict machine efficiencies with error averaging around 1% over all operating conditions for multiple machine types, and capture transient behavior of the units. To demonstrate the utility as a virtual optimization tool, design of a complete external gear machine design will be performed. This demonstration will start from only analytical parameters, and will track a route to a complete prototype.

APA, Harvard, Vancouver, ISO, and other styles

48

Rego, João Manuel Nunes de Oliveira. "Industrialização de Máquina de Inspeção Automática; Melhoria para Tolerância Reduzida de Folga entre Pontas de Anel de Pistão." Master's thesis, 2020. http://hdl.handle.net/10316/94049.

Full text

Abstract:

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
Piston rings are at the top of the precision in the automotive industry, in addition to the need for 0% failures, also reduced tolerances are needed. Some measurement systems prove not to attend the product's tolerances in the short term, the philosophy of continuous improvement at MAHLE anticipate this phenomenon.The 100% dimensional control of piston ring’s gap is done by the IPL machines, characterized by contact inspection, whose can cause causing splinters on gap. Also, these Machines have excessive variation on their measurementsA Dimensional Inspection Machine (MID-01) is in the approval stages, which opens the opportunity to research and develop the truth machine capability. The gap between points is the most critical point to be investigated: the need to measure without contact; the difficulty of obtaining edges for the processing and calculation the gap measurement, are among the problems.The inspection with confidence and robustness to a tolerance of 0.100 mm is already guaranteed by MID. Variations of up to 0.010 mm between measurements are limits for operation work. A case study of cause-and-effect analysis to assess the sources of variability in measurements will be carried out, together with the performance of improvement actions and their gains.The analysis of results reveals improvement effects, achieving, in the end, a maximum of 0.005 mm of variation between measurements, revealing the possibility of 100% dimension inspection with 0.050 mm of tolerance.In order to increase the robustness of the results, future proposals for improvement will also be presented, essential for the inspection of reduced tolerances in the manufacturing environment.
Os anéis de pistão estão no topo da exigência na indústria automóvel, além da necessidade de 0% falhas, temos também tolerâncias reduzidas. A inspeção dimensional automática através de visão artificial vai ser estudada. Outros sistemas de medição para a folga entre pontas de anéis de pistão provam não ser capazes de atender as tolerâncias do produto a curto prazo, uma medida intrínseca à filosofia de melhoria contínua na MAHLE, antecipa este fenómeno.O controlo dimensional da folga entre pontas é controlado a 100% pelas IPL (Máquina de Inspeção Linear), caracterizadas pela inspeção por contacto, o que pode provocar lascas nas pontas. Normalmente estas máquinas apresentam variação excessiva nas suas medições.A máquina de inspeção automática utilizada neste estudo (MID) encontra-se em fase de aprovação, o que gerou a oportunidade de pesquisar e desenvolver as suas capacidades. A folga entre pontas é o ponto mais crítico a ser estudado: a necessidade de inspeção sem contacto, a dificuldade de obtenção de arestas para o cálculo pelas câmaras, aliados aos limites de especificação de até 0,050 mm, estão entre os problemas.A inspeção com confiança e robustez para tolerância de 0,100 mm já é garantido pela MID. Variações de até 0,010 mm entre medições são limite para o funcionamento. Um caso de estudo de análise de causa efeito em busca de combater as fontes de variabilidade nas medições vai ser realizado, juntamente com a realização de ações de melhoria e os seus ganhos.A análise de resultados revela efeitos de melhoria, conseguindo no final obter um máximo de 0,005 mm de variação entre medições, revelando a possibilidade de medição de cota com 0,050 mm de tolerância.Com vista a aumentar a robustez dos resultados, vão também ser apresentadas propostas futuras de melhoria, essenciais para a inspeção de tolerâncias reduzidas no meio fabril.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Machine pistols'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles