Download or read book Predictive Modeling of Piston Assembly Lubrication in Reciprocating Internal Combustion Engines written by Huijie Xu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Piston Skirt Lubrication in Internal Combustion Engines written by Dongfang Bai (Ph. D.) and published by . This book was released on 2012 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ever-increasing demand for reduction of the undesirable emissions from the internal combustion engines propels broader effort in auto industry to design more fuel efficient engines. One of the major focuses is the reduction of engine mechanical losses, to which the friction of the piston skirt is one important contributor. Yet there lacks a sufficient understanding of the skirt lubrication behavior to effectively optimize the piston skirt system in practice. The ultimate goal of this work is to develop a comprehensive model to advance the predictability of the skirt friction while integrating all the dynamic behavior of the piston secondary motion and the structural deformation of the piston skirt and cylinder liner. Major contributions of this work are analysis of and development of a model for the oil transport and exchange of the piston skirt region and its surroundings. The new oil transport model is composed with two elements. First, the oil scraped into the chamfer region by the oil control ring during a down-stroke is tracked and its accumulation and release to the skirt region are modeled. Second, oil separation and re-attachment are allowed in the skirt region, breaking conventional full-attachment assumption in lubrication studies. The new oil transport model together with hydrodynamic and boundary lubrication model were coupled with piston secondary motion and structural deformation of the piston skirt and cylinder liner. For numerical efficiency and physics clarity, we used different discretization for the lubrication from the structural deformation. The final model is robust and efficient. The discussion of the model results is focused mainly on the oil transport. There exist a general pattern in available oil for skirt lubrication, namely, skirt tends to be starved when it travels at the upper portion of a stroke. Comparison with visualization experiment for oil accumulation patterns show consistency between model prediction and observation. This work represents a major step forward to realistically predicting skirt friction and the influence of all the relevant design and operational parameters. However, oil supply to the region below the piston skirt can largely influence the outcome of the friction prediction and its mechanism is system dependent. Additionally, simple treatment of the oil transport in the current model is merely a first step to modeling the complex fluid problems involved. Improvements of this model based on application and further analysis will make it a more powerful engineering tool to optimize the skirt system to minimize its undesirable outputs.

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 Modeling of Piston Pin Lubrication in Internal Combustion Engines written by Zhen Meng (Ph.D.) and published by . This book was released on 2020 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: The piston pin joins the piston and the connecting rod to transfer the linear force on the piston to rotate the crankshaft that is the eventual power outlet of the engine. The interfaces between the piston pin and the pin bore as well as the connecting rod small end are one of the most heavily loaded tribo pairs in engines. Piston pin seizure still occurs often in the engine development and the solution often comes from applying expensive coatings. Furthermore, it has been found that the friction loss associated with the pin can be a significant contributor to the total engine mechanical loss. Yet, there lacks a basic understanding of the lubrication behavior of the pin interfaces. This work is aimed to develop a piston pin lubrication model with consideration of all the important mechanical processes. The model predicts the dynamics of the pin and the lubrication of the interfaces between the pin and pin bore as well as small end. The model couples the dynamics of the pin with the structural deformation of the mating parts, the hydrodynamic and boundary lubrication of all the interfaces, and oil transport. The model is successfully implemented with an efficient and robust numerical solver with the second order accuracy to compute this highly stiff system. The preliminary results applying the model to a gasoline engine show that the boundary lubrication is the predominant contributor to the total friction. As a result, the interface with more asperity contact tends to hold the pin with it. Thus, the pin friction loss is coming from the interface with less contact. Solely from friction reduction point of view, ensuring efficient hydrodynamics lubrication in one interface is sufficient. Furthermore, as the heavy load is supported in several small areas, mechanical and thermal deformation of all the parts are critical to load distribution, oil transport, and the generation of hydrodynamic and asperity contact pressure, providing the necessity of the elements integrated in the model. This work represents the first step to establishing a more comprehensive engineering model that helps the industry understand the pin lubrication and find cost-effective solutions to overcome the existing challenges.

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 Internal Combustion Engines written by Allan T. Kirkpatrick and published by John Wiley & Sons. This book was released on 2020-08-28 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive resource covering the foundational thermal-fluid sciences and engineering analysis techniques used to design and develop internal combustion engines Internal Combustion Engines: Applied Thermosciences, Fourth Edition combines foundational thermal-fluid sciences with engineering analysis techniques for modeling and predicting the performance of internal combustion engines. This new 4th edition includes brand new material on: New engine technologies and concepts Effects of engine speed on performance and emissions Fluid mechanics of intake and exhaust flow in engines Turbocharger and supercharger performance analysis Chemical kinetic modeling, reaction mechanisms, and emissions Advanced combustion processes including low temperature combustion Piston, ring and journal bearing friction analysis The 4th Edition expands on the combined analytical and numerical approaches used successfully in previous editions. Students and engineers are provided with several new tools for applying the fundamental principles of thermodynamics, fluid mechanics, and heat transfer to internal combustion engines. Each chapter includes MATLAB programs and examples showing how to perform detailed engineering computations. The chapters also have an increased number of homework problems with which the reader can gauge their progress and retention. All the software is ‘open source’ so that readers can see in detail how computational analysis and the design of engines is performed. A companion website is also provided, offering access to the MATLAB computer programs.

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 Analytic and Numerical Study of Lubrication Dynamics for Internal Combustion Engine Piston Assemblies and Journal Bearings written by Qianfan Xin and published by . This book was released on 1999 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of a Numerical Model of Piston Secondary Motion for Internal Combustion Engines written by Conor Peter McNally and published by . This book was released on 2000 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Frontiers of Tribology written by Roberts and published by CRC Press. This book was released on 1992-01-01 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Topics addressed at the April 1991 conference held in Stratford-upon- Avon, UK, and sponsored by the Tribology Group of the Institute of Physics (UK), include adhesion, boundary lubrication, friction, fluid film lubrication, surface analysis, lubricant additives, and other physical aspects, with particular focus on underlying mechanisms. No index. Annotation copyrighted by Book News, Inc., Portland, OR

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.

Download or read book Pistons and engine testing written by MAHLE International GmbH and published by Springer Vieweg. This book was released on 2018-10-30 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ever-increasing demands placed on combustion engines are just as great when it comes to this centerpiece—the piston. Achieving less weight or friction, or even greater wear resistance, requires in-depth knowledge of the processes taking place inside the engine, suitable materials, and appropriate design and manufacturing processes for pistons, including the necessary testing measures. It is no longer possible for professionals in automotive engineering to manage without specific expertise of this kind, whether they work in the field of design, development, testing, or maintenance. This technical book answers these questions in detail and in a very clear and comprehensible way. In this second, revised edition, every chapter has been revised and expanded. The chapter on “Engine testing”, for example, now include extensive results in the area of friction power loss measurement and lube oil consumption measurement.

Download or read book Modeling the Effects of Piston Skirt Distortion on the Design of Pistons for Optimum Lubrication in a Reciprocating Engine written by William Lawrence Blair and published by . This book was released on 1989 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Engine Tribology written by C.M. Taylor and published by Elsevier. This book was released on 1993-07-23 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: Customer expectations and international competition are obliging car and commercial vehicle manufacturers to produce more efficient and cleaner products in shorter product cycle times. The consideration of Engine Tribology has a leading role to play in helping to achieve these goals. Specific areas of interdisciplinary interest include: design influences on fuel economy and emissions; new materials (ceramics, steels, coatings, lubricants, additives); low viscosity lubricants; and low heat rejection (adiabatic) engines. This volume gives a detailed and current review on some basic features of tribology particularly associated with internal combustion engines such as: lubrication analysis relevant to plain bearings, Hertzian contact theory and elastohydrodynamic lubrication associated with cams and followers and friction and wear in a general context. Several chapters examine engine bearings, valve trains, (cams and followers) and piston assemblies. For each machine element a background introduction is followed by design interpretations and a consideration of future developments. The important topic of materials, solids and lubricants is focused upon in the concluding chapters. The work will be of interest to engineers and researchers in the automobile, automotive products, petroleum and associated industries.

Download or read book Developing an Approach Utilizing Local Deterministic Analysis to Predict the Cycle Friction of the Piston Ring pack in Internal Combustion Engines written by Yang Liu (S.M.) and published by . This book was released on 2013 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, a rapid growth of internal combustion (IC) engines is considered to be a major contributor to energy crisis. About 20% of the mechanical loss in internal combustion engines directly goes to the friction loss between piston ring pack and liner finish. A twin-land oil control ring (TLOCR) deterministic model was developed by Chen et al. and it helps the automotive companies investigate the effects of liner finish, rings, and lubricants on friction and oil control of the TLOCR [2]. This work focuses on application of the TLOCR model and extension of the deterministic model to the top two rings. First, there are some practical challenges in the application of Chen's TLOCR deterministic model. Due to different wear condition on the same liner, surface roughness varies from spot to spot. A small patch of measurement cannot provide enough information and the change of plateau roughness makes the contact model unreliable. As a result, a multi-point correlation method was proposed to combine the information of different spots from the same liner and this method was shown to give better match to the experimental results. A top-two-ring lubrication cycle model was developed based on the multiphase deterministic model by Li. et al [30] and previous top-two-ring lubrication model by Chen. Et al [2][31]. The model is composed with two parts. First, the deterministic model is used to generate a correlation between the hydrodynamic pressure/friction and the minimum clearance with prescribed oil supply from the deterministic oil control ring model. It was found that within reasonable accuracy, the gas pressure effect on the hydrodynamic lubrication of the top two rings can be decoupled from the hydrodynamic lubrication. Thus, only single-phase deterministic model was needed to generate the correlation. This decoupling significantly reduces the computation time. Then, a cycle model was developed utilizing the correlation of hydrodynamic pressure/friction and the minimum clearance. The cycle model considers the effect of gas pressure variations in different ring pack regions as well as the dynamic twist of the top two rings. Finally, the models were used to examine the friction and lubrication of three different liner finishes in an actual engine running cycle.