Download or read book Introduction to Modeling and Simulation of Piston Ring Lubrication written by Ali Usman and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book include elementary study of Piston-Ring lubrication in Hydrodynamics (HL) and Elasto-Hydrodynamic (EHL) domain at low load-low speed operating conditions. Effects of Piston-Ring running face profile, Engine speed and Elliptically distorted bore are investigated. Vogelpohl parameter technique along with Finite Difference Method is used to solve steady state Reynolds equation for Compression ring of a gasoline engine. Performance parameters (Oil Film thickness in HL and EHL, Friction Force, Power Loss and Flow-rate of lubricating oil) are shown graphically and explained.
Download or read book Modeling of Piston Ring Dynamics Crevice Gas Flow and Hydrodynamic Lubrication in Internal Combustion Engines written by Riadh Namouchi and published by . This book was released on 1990 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Lubrication of the Piston Ring Pack in Internal Combustion Engines Using the Deterministic Method written by Haijie Chen and published by . This book was released on 2011 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piston ring packs are used in internal combustion engines to seal both the high pressure gas in the combustion chamber and the lubricant oil in the crank case. The interaction between the piston ring pack and the cylinder bore contributes substantially to the total friction power loss for IC engines. The aim of this thesis work is to advance the understanding of the ring liner lubrication through numerical modeling. A twin-land oil control ring lubrication model and a top two-ring lubrication model are developed based on a deterministic approach. The models take into consideration the effect of both the liner finish micro geometry and the ring face macro profile. The liner finish effect is evaluated on a 3D deterministically measured liner finish patch, with fully-flooded oil supply condition to the oil control rings and starved oil supply condition to the top two rings. Correlations based on deterministic calculations and proper scaling are developed to connect the average hydrodynamic pressure and friction to the critical geometrical parameters and operating parameters so that cycle evaluation of the ring lubrication can be performed in an efficient manner. The models can be used for ring pack friction prediction, and ring pack/liner design optimization based on the trade-off of friction power loss and oil consumption. To provide further insights to the effect of liner finish, a wear model is then developed to simulate the liner surface geometry evolution during the break-in/wear process. The model is based on the idea of simulated repetitive grinding on the plateau part of the liner finish using a random grinder. The model successfully captures the statistic topological features of the worn liner roughness. Combining the piston ring pack model and the liner finish wear model, one can potentially predict the long term ring pack friction loss. Finally the thesis covers the experimental validation of the twin-land oil control ring model using floating liner engine friction measurements. The modeled ring friction is compared with the experimental measurement under different ring designs and liner finishes. The result shows that the model in general successfully predicts the friction force of the twin-land oil control ring/liner pair.
Download or read book Modeling the Effects of Liner Pores on Piston Ring Lubrication in Internal Combustion Engines written by Jérôme Sacherer and published by . This book was released on 2019 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Automotive manufacturers are increasingly replacing traditional cast iron liners in the internal combustion engines of commercial vehicles with spray-coated liners. While not the original intention, these new, porous liners are suspected to reduce hydrodynamic friction. The interaction of pores with piston ring and liner lubrication is studied in this work. Preliminary computational fluid dynamics simulations are performed on a single, idealized pore geometry, including surface tension but no cavitation due to computational cost limitations. Potential mechanisms for displacement of oil out of the pore are investigated, as this would improve subsequent ring lubrication. Pressure-driven flow is found to dominate this process, though surface tension also has an impact: it can trap air bubbles in the pore and level out accumulated oil back into the evacuated pore. A deterministic model exists to predict hydrodynamic pressure and friction for rough and honed liner surfaces. This model, however, assumes fully flooded boundary conditions. A modification to the governing equation for the regions beyond the full film boundaries is developed by introducing a diffusive velocity profile. The diffusion provides a transition between an oil film on the liner experiencing uniform flow to full film Couette flow. This change enables the large pore geometry to be accommodated by the model without unrealistic premature film attachment all the while maintaining the continuous transition between full film and cavitation. Results from the model indicate that the pore can act as an oil supply, extending the wetting region beneath the ring and consequently allowing for greater pressure generation and larger, desirable load carrying capacity. Cavitation also plays a critical role in the pore interaction; early cavitation in the pore can split the full film region, significantly compromising the load carrying capacity. Cavitation is also found to potentially make use of the pore's oil supply to redistribute oil onto the liner. In general, the pore causes a substantial drop in lift force, increasing the coefficient of friction as a result, though in some cases an extended wetting region can counter this effect.
Download or read book Modeling the Performance of the Piston Ring pack with Consideration of Non axisymmetric Characteristics of the Power Cylinder System in Internal Combustion Engines written by Liang Liu and published by . This book was released on 2005 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) This model predicts the inter-ring gas pressure and 3-D displacements of the three rings at various circumferential locations. Model results show significant variations of the dynamic behavior along ring circumference. In the ring-pack lubrication model, an improved flow continuity algorithm is implemented in the ring/liner hydrodynamic lubrication, and proves to be very practicable. By coupling the ring/liner lubrication with the in-plane structural response of the ring, the lubrication along the entire ring circumference can be calculated. Model results show significant variations of lubrication along the circumference due to the non-axisymmetric characteristics of the power cylinder system. Bore distortion was found to have profound effects on oil transport along the liner. Particularly, it stimulates the occurrence of oil up-scraping by the top ring during compression stroke. Because the oil evaporation on the liner affects the liner oil film thickness, a sub-model for liner evaporation with consideration of multi-species oil is incorporated with the lubrication model. With consideration of oil transport along the liner, the prediction of evaporation is more precise. The combination of these models is a complete package for piston ring-pack analysis. It is computationally robust and efficient, and thus has appreciable practical value.
Download or read book Numerical Modeling of Piston Secondary Motion and Skirt Lubrication in Internal Combustion Engines written by Fiona McClure and published by . This book was released on 2007 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal combustion engines dominate transportation of people and goods, contributing significantly to air pollution, and requiring large amounts of fossil fuels. With increasing public concern about the environment and the reliability of oil supplies, automotive companies are pushed to improve engine design in order to reduce engine emissions and fuel consumption. This project aims to develop a numerical model of piston dynamics and lubrication in internal combustion engines, enabling prediction of friction generation at the piston -cylinder bore interface, and oil transport in the power cylinder system. It is currently estimated that the piston - cylinder bore friction accounts for up to 25% of the power loss in a typical engine, while oil transported to the combustion chamber by the piston and ring-pack contributes significantly to engine emissions. A dry piston model was first developed to allow fast calculation of approximate piston dynamics. An elastohydrodynamic lubrication model was then developed to allow direct numerical simulation of the effect of piston tooling marks, and comparison with results obtained using an Average Reynolds equation with flow factors. The lubrication model was incorporated into the piston dynamics model, enabling more accurate evaluation of friction and oil transport. Comparison between the dry and lubricated model results demonstrate the effect of oil film thickness on piston lateral motion, tilt, friction generation and oil transport.
Download or read book Piston Ring and Cylinder Bore Friction Simulation in Mixed Lubrication Regime written by Ozgen Akalin and published by . This book was released on 1999 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Piston ring Assembly Friction Measurement and Modeling written by Shyh-Shyan Lin and published by . This book was released on 1993 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Modeling and Control of Internal Combustion Engine Systems written by Lino Guzzella and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal combustion engines still have a potential for substantial improvements, particularly with regard to fuel efficiency and environmental compatibility. These goals can be achieved with help of control systems. Modeling and Control of Internal Combustion Engines (ICE) addresses these issues by offering an introduction to cost-effective model-based control system design for ICE. The primary emphasis is put on the ICE and its auxiliary devices. Mathematical models for these processes are developed in the text and selected feedforward and feedback control problems are discussed. The appendix contains a summary of the most important controller analysis and design methods, and a case study that analyzes a simplified idle-speed control problem. The book is written for students interested in the design of classical and novel ICE control systems.
Download or read book A Multi scale Model for Piston Ring Dynamics Lubrication and Oil Transport in Internal Combustion Engines written by Camille Baelden and published by . This book was released on 2014 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel consumption reduction of more than 20% can be achieved through engine friction reduction. Piston and piston rings contribute approximately half of the total engine friction and are therefore central to friction reduction efforts. The most common method to reduce mechanical losses from piston rings has been to lower ring tension, the normal force providing sealing between the piston ring and the cylinder liner. However tension reduction can result in additional lubricant consumption. The objective of this thesis is to understand and model the physical mechanisms resulting in flow of oil to the combustion chamber in order to achieve optimal designs of piston rings. The optimal design is a compromise between friction reduction and adequate gas and lubricant sealing performance. To do so a multi-scale curved beam finite element model of piston ring is developed. It is built to couple ring deformation, dynamics and contact with the piston and the cylinder. Oil flow at the interfaces between the ring and the cylinder liner and between the ring and the piston groove can thus be simulated. The piston ring model is used to study the sealing performance of the Oil Control Ring (OCR), whose function is to limit the amount of oil supplied to the ring pack. The contributions of the three main mechanisms previously identified, to oil flow past the OCR are quantified: - Deformation of the cylinder under operating conditions can lead to a loss of contact between the ring and the liner. - Tilting of the piston around its pin can force the OCR to twist and scrape oil from the liner. - Oil accumulating below the OCR can flow to the groove and leak on the top of the OCR The OCR is found to be flexible enough to limit the impact of cylinder deformation on oil consumption. Both ring scraping and flow through the OCR groove can contribute to oil consumption in the range of engine running conditions simulated. Reduction of scraping is possible by increasing the ability of both OCR lands to maintain contact with the liner regardless of piston groove tilt. The flow of oil through the OCR groove can be reduced by designing appropriate draining of oil in the groove and an adequate oil reservoir below the OCR. The piston ring oil transport model developed in this thesis will be a valuable tool to optimize ring pack designs to achieve further ring pack friction reduction without increasing oil consumption.
Download or read book Computational Analysis of Piston Ring Wear and Oil Consumption for an Internal Combustion Engine written by Boon-Keat Chui and published by . This book was released on 2001 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Piston Secondary Motion and Skirt Lubrication with Applications written by Pasquale Pio Totaro and published by . This book was released on 2014 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interest in reducing emission and improving engine efficiency has become a major push in industry, due to upcoming stricter regulations. A great deal of attention has been given to the frictional losses due to piston and liner interaction, as they represent a significant portion of the total mechanical losses. This thesis work focuses on further development and application of an existing model for the piston's secondary motion and skirt lubrication. Model development has been focused on introducing liner dynamic deformation, temperature and shear-thinning effect on viscosity, and arbitrary skirt's shape definition. The theory behind the inclusion of these components is discussed and the modifications to the existing model are explained. In regards to the model's applications, an important topic is the model validation, for which friction results from simulations are compared with experimental results obtained on a floating liner engine. The analysis covers the running condition of 1000 rpm, at partial and full load. This study is, however, not concluded and more cases need to be studied in order to complete the validation of the model. The second application focuses on the effects of geometrical patterns on the skirt on friction and secondary motion of the piston. First, some regular patterns were studied and found to have negative effects on friction due to their inability to build sufficient hydrodynamic pressure, compared to the baseline design. Then, a different sets of patterns were proposed to more effectively utilize available oil and to maximize the hydrodynamic pressure generation in the skirt region. The results show that new strategy can significantly reduce friction of the skirt without introducing negative impact on the secondary motion. This thesis work aims to make the model a more complete and powerful tool to understand piston's secondary motion and the applications are meant to show the capabilities of the model, as an instrument to approach piston's design and inspire new ways and ideas to reduce frictional losses.
Download or read book Fluid Mechanics of Lubricant Transport in Non contact Regions in the Piston Ring Pack in Internal Combustion Engines written by Tianshi Fang and published by . This book was released on 2019 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compromise between friction and lubricant consumption has been a long-lasting challenge for the design of the piston ring pack in internal combustion engines. In order to achieve a satisfactory compromise, a systematic understanding of the lubricant transport in the piston ring pack is of critical importance. In the context of increasingly stringent standards on engine emissions, there is a more urgent need for the knowledge on the lubricant transport. This work is focused on the lubricant transport in two non-contact regions in the piston ring pack: 1) the region near a piston skirt chamfer; 2) the region near a piston third land. While the Reynolds equation has been widely employed to model the contact interfaces, more general fluid mechanics has to be applied in the non-contact regions. This thesis is the first work to comprehensively apply Computational Fluid Dynamics (CFD) and theoretical modelling to the non-contact regions in the piston ring pack. CFD was employed to fundamentally understand the lubricant transport, and theoretical models were developed to more efficiently quantify the lubricant transport. This work is a major step towards an accurate quantification of the lubricant leakage through the oil control ring (OCR) that can be critical to the lubricant consumption. The lubricant transport in a skirt chamfer region determines the pressure outside the contact interface between the lower flank of the OCR and its groove, and thus the lubricant flow rate into the OCR groove. A numerical model and a closed-form correlation were developed to efficiently predict the pressure. While the lubricant transport into the OCR groove had often been overlooked, this work revealed that this lubricant transport could be remarkable. In the region near a piston third land, two mechanisms of lubricant transport were studied: 1) high-speed bridging; 2) reattachment. Both of them introduce additional lubricant to the ring/liner contact interfaces. The effects on the inlet conditions to the ring/liner contact interfaces were quantitatively studied. The existing knowledge on high-speed bridging was enhanced in a quantitative sense. The reattachment process was first discovered and studied.
Download or read book Proceedings of the World Tribology Congress III 2005 written by and published by . This book was released on 2005 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Structural Behavior of the Piston Rings Under Different Boundary Conditions in Internal Combustion Engines written by Dian Xu and published by . This book was released on 2010 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the process of designing internal combustion engine, piston ring plays an important role in fulfilling the requirements of camber gas sealing, friction reduction and lubrication oil consumption. The goal of this thesis is to have a better understanding of the ring behaviors under different working conditions in a structural level. This thesis is an extension of existing ring design tool. A model is built up to simulate the processes of changing ring states from one to another such as free or fit the ring. It revealed the sensitive characters of the piston ring tip; it expanded the field of application of the existing piston ring design tool; it also investigated the ring bore interaction in more conditions. This work removed the symmetric assumption in the existing tool. A new method that calculates ring free shape and ring bore contact force from ring ovality data is introduced for the first time. The analysis of ring bore interaction is widened. The model was applied to an industry ring design case. In this case it shows the free and fit procedure in this model is physically and mathematically reversible. It shows these procedures are direction independent. The contact force distribution changes when the ring is moving within the distorted bore. It also changes when the wetting or roughness situation is different. This model can calculate the ring free shape from asymmetric measured ovality data. It can also retrieve the desired contact force from it. The piston ring design tool is updated and implemented with these highly appreciable new features. This complete package has high efficiency and a wider practical field.
Download or read book Piston Ring Pack Friction and Lubrication Analysis of an Automotive Engine Using a Mixed Lubrication Model written by Ping C. Sui and published by . This book was released on 1993 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling of Contact Between Liner Finish and Piston Ring in Internal Combustion Engines Based on 3D Measured Surface written by Qing Zhao (S.M.) and published by . This book was released on 2014 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: When decreasing of fossil fuel supplies and air pollution are two major society problems in the 21st century, rapid growth of internal combustion (IC) engines serves as a main producer of these two problems. In order to increase fuel efficiency, mechanical loss should be controlled in internal combustion engines. Interaction between piston ring pack and cylinder liner finish accounts for nearly 20 percent of the mechanical losses within an internal combustion engine, and is an important factor that affects the lubricant oil consumption. Among the total friction between piston ring pack and cylinder liner, boundary friction occurs when piston is at low speed and there is direct contact between rings and liners. This work focuses on prediction of contact between piston ring and liner finish based on 3D measured surface and different methods are compared. In previous twin-land oil control ring (TLOCR) deterministic model, Greenwood-Tripp correlation function was used to determine contact. The practical challenge for this single equation is that real plateau roughness makes it unreliable. As a result, micro geometry of liner surface needs to be obtained through white light interferometry device or confocal equipment to conduct contact model. Based on real geometry of liner finish and the assumption that ring surface is ideally smooth, contact can be predicted by three different models which were developed by using statistical Greenwood-Williamson model, Hertzian contact and revised deterministic dry contact model by Professor A.A. Lubrecht. The predicted contact between liner finish and piston ring is then combined with hydrodynamic pressure caused by lubricant which was examined using TLOCR deterministic model by Chen. et al to get total friction resulted on the surface of liner finish. Finally, contact model is used to examine friction of different liners in an actual engine running cycle.
