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 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 of Liner Finish Effects on Oil Control Ring Lubrication in Internal Combustion Engines Based on Deterministic Method written by Haijie Chen and published by . This book was released on 2008 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) These key parameters include the surface wavelength of the plateau part, the frequency of deep valleys and the honing cross-hatch angle. This thesis work has opened a window on the deterministic study of the functionality of cylinder liner surface texture.

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 Effects of Lubricant Viscosity and Surface Texturing on Ring pack Performance in Internal Combustion Engines written by Rosalind Kazuko Takata and published by . This book was released on 2006 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The piston ring-pack contributes approximately 25% of the mechanical losses in an internal combustion engine. Both lubricant viscosity and surface texturing were investigated in an effort to reduce this ring-pack friction and increase engine efficiency. While both optimizing viscosity and surface texturing are predicted to cause a reduction in ring/liner friction individually, a combined approach may cause an even greater friction reduction while mitigating unwanted side-effects such as oil consumption and wear. Existing MIT models, with some modifications and supplementary programs to allow investigation of the parameters of interest, were used to conduct this research. A ring-pack model based on average flow-factor Reynolds analysis was used for both studies, with a modified form of this program, along with a supplementary deterministic model for surface analysis, used for the study of surface texturing. Although these advanced models are applicable in a wide range of cases, the surface textures studied in this research are very different than a typical cylinder liner surface, and can be represented only approximately by the averaged Reynolds analysis upon which the ring simulation is based.

Download or read book Modeling of Two body Fatigue Wear of Cylinder Liner in Internal Combustion Engines During the Break in Period and Its Impact on Engine Lubrication written by Chongjie Gu and published by . This book was released on 2017 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal combustion engines are widely utilized in modem automobiles. Around 10% of the total fuel energy is dissipated to heat due to mechanical friction, among which 20% is caused by the contact between the cylinder liner and the piston rings. The wear of cylinder liner not only leads to surface damage, but also results in the change of liner lubrication conditions. Therefore, a large number of tests are performed by researchers to investigate the liner wear process and its impact on engine lubrication. This work is the first step toward developing a wear model to predict the evolution of liner roughness and ring pack lubrication during break-in period. A physics-based liner wear model is built in this work, with focus on two mechanisms: surface plastic flattening and fatigue wear. Both mechanisms are simulated through a set of governing equations and are coupled together to complete the algorithm of the liner wear model. Simulations of break-in wear are performed to different liner surfaces finishes, with different external normal pressures. Simulation results indicate that the liner wear rate depends on the size and shape of liner surface asperities, which may provide guidance for surface manufacturing. The results also show consistence with the Archard's wear law, describing the proportional correlation between normal pressure and steady state wear rate. This wear model is then used to study the influence of liner wear on engine lubrication. Through the friction for entire engine cycles, simulated results are compared with experimental friction measurements. The comparison shows that the calculated friction evolution during break-in has the same trend and comparable magnitude as the measurements, indicating the efficiency of the wear model. Some initial work of modeling of third-body abrasive wear is also discussed in this thesis.

Download or read book Computations and Modeling of Oil Transport Between Piston Lands and Liner in Internal Combustion Engines written by Tianshi Fang and published by . This book was released on 2014 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The consumption of lubricating oil in internal combustion engines is a continuous interest for engine developers and remains to be one of the least understood areas. A better understanding on oil transport is critical to an optimization of engine designs, and advanced analytical tools are essential to the achievement of reduced frictions without compromising oil consumption. Oil transport from piston lands to a liner, hereafter called "bridging", has been observed in engine tests. The additional oil transferred to the liner becomes a potential source of oil consumption through ring-liner interaction. Thus, it is important to develop more quantitative models to better analyze bridging. The objective of this work is to obtain a more in-depth understanding on the oil transport between piston lands and liner and provide quantitative models of the oil transport mechanisms. Multiphase Computational Fluid Dynamics (CFD) was employed together with analyses of experimental observations. Three categories of bridging were identified: assisted bridging, self-sustained bridging, and reverse bridging. While assisted bridging involves an axial oil flow across an entire piston land, the other two phenomena are localized and become prominent at low engine speeds. The mechanisms of each phenomenon were analyzed in this work. Correlations and theoretical models were developed to associate the risk of bridging with geometrical designs of a piston and operating conditions of an engine. Particularly, the theoretical model of self-sustained bridging contributes to the optimization of geometrical designs of the third land of a piston ring pack. This work constitutes a major step towards a further quantification of oil transport. Some findings and models presented in this work can readily contribute to providing optimal solutions to certain piston regions. Furthermore, the results of this work serve broader purposes in providing boundary conditions to other interactions in a piston ring pack.

Download or read book Effects of Lubricant Viscosity and Surface Texturing on Ring pack Performance in Internal Combustion Engines written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The piston ring-pack contributes approximately 25% of the mechanical losses in an internal combustion engine. Both lubricant viscosity and surface texturing were investigated in an effort to reduce this ring-pack friction and increase engine efficiency. While both optimizing viscosity and surface texturing are predicted to cause a reduction in ring/liner friction individually, a combined approach may cause an even greater friction reduction while mitigating unwanted side-effects such as oil consumption and wear. Existing MIT models, with some modifications and supplementary programs to allow investigation of the parameters of interest, were used to conduct this research. A ring-pack model based on average flow-factor Reynolds analysis was used for both studies, with a modified form of this program, along with a supplementary deterministic model for surface analysis, used for the study of surface texturing. Although these advanced models are applicable in a wide range of cases, the surface textures studied in this research are very different than a typical cylinder liner surface, and can be represented only approximately by the averaged Reynolds analysis upon which the ring simulation is based.

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.

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 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 Modeling the Evolution of Composition of the Fuel and Lubricant Mixture on the Cylinder Wall in Internal Combustion Engines written by Vinayak Teja Kalva and published by . This book was released on 2017 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improvements in engine efficiency are necessary for the advancement of modem engine technology. Fuels and lubricants used in internal combustion (IC) engines play an important role in governing the engine efficiency. In IC engines some amount of fuel spray can eventually end up on the cylinder liner. This fuel spray mixes with the oil (lubricant) present on the liner. Now the liquid layer on the liner consists of fuel and oil (fuel-oil film is formed) which interacts with the piston rings and the up-scraping of the fuel-oil film can cause the release of oil droplets into the combustion chamber. The released oil droplets lower the self-ignition temperature of the fuel vapor which might lead to pre-ignition. Pre-ignition is a phenomenon in which the fuel vapor ignites before the spark plug fires causing huge pressure rise which can be detrimental for the engine. The fuel spray on the liner can also pass through the piston rings during the compression stroke and can cause oil dilution in the crank case. The current work is mainly focused on analyzing the fuel-oil interaction on the cylinder liner. A numerical model has been developed in which fuel was modeled as a mixture of 10 hydrocarbon components and oil was modeled as a single n-alkane hydrocarbon. In this model, diffusion in the film, heat transfer in the film, and vaporization at the film-air interface have been coupled. Moving boundary (due to vaporization) was handled by solving the time required to remove the outermost layer while utilizing regular meshing. Implicit method and Newton's iteration method were used to ensure numerical stability and efficiency. Eventually the model calculates the remaining mixture thickness and content before the piston comes back to the specified location in the compression stroke. Some of the main inputs to the model are timing and location of the fuel droplets depositing on the liner, initial fuel film thickness, initial oil film thickness, liner temperature, and cylinder gas pressure. The results showed that with typical engine operational parameters, substantial portion of the initial film mixture still remains when the piston comes back if the initial fuel film thickness is in the range of 20 pm. Further studies were made to examine the consequences of the remaining mixture on the liner. A brief quantitative study was performed to compare the fuel-oil scraped volume and crevice volume. Additionally, the increase in ring-liner contact force due to local oil dilution on the liner was examined using an existing ring-liner lubrication model.

Download or read book The Influence of Honing on the Wear of Ceramic Coated Piston Rings and Cylinder Liners written by Kevin C. Radil and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reciprocating wear tests were performed to investigate the effects of honing on the wear of ceramic coated piston rings and cylinder liners. The baseline or control cases consisted of testing ceramic coated rings against ceramic coated liner specimens whose surfaces were ground and lapped smooth. A second series of tests were performed with liner specimens with base and plateau honed surfaces. Test conditions were chosen to simulate the temperatures, pressures, and boundary lubricated conditions present at top ring reversal in a conventional diesel engine. Wear factor comparisons between the baseline cases and the tests with the honed liner specimens indicate that honing alone is not sufficient to ensure an improvement in ring and liner wear.

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 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 A Multi scale Model Integrating Both Global Ring Pack Behavior and Local Oil Transport in Internal Combustion Engines written by Yang Liu (Ph. D.) and published by . This book was released on 2017 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improving fuel economy of internal combustion engines is one of the major focuses in automotive industry. The piston ring friction contributes as much as 25% of total mechanical loss in internal combustion engines [1] and is an area of great interests to the automotive industry in their overall effort to improve engine efficiency. However, typical methods to reduce friction loss from piston ring pack, such as ring tension reduction, may cause additional oil consumption. A compromise between reduction of friction loss and control of gas leakage and oil consumption needs to be made, which requires a deep understanding of oil transport mechanism. This compromise gives rise to the interest in modeling work. Both experimental results and previous experience showed that oil film distribution on the piston varies significantly along the circumference and the oil leakage occurs locally. Therefore to predict oil transfer across different ring pack regions, one needs to integrate both global and local processes. This work is aimed at establishing an enduring framework for all the cycle-based processes at different length scales. As a first step, a multi-scale multi-physics piston ring pack model was developed by coupling the structural dynamics of the piston rings with gas flows and local interactions at ring-groove and ring-liner interfaces. A curved beam finite element method was adopted to calculate the ring structural response to interaction between the ring and the liner as well as the ring and the groove. Compared to a traditional straight beam finite element method, the curved beam separates the structural mesh and contact grid by utilizing the shape functions. In this work, a multi-length-scale ring pack model was, for the first time, successfully assembled. This model bears its fundamental values to truly reflect the integral results of all the relevant mechanisms. The significance of the current work is that it demonstrated such an integration of all the length scales is possible for a cycle model with a reasonable computation cost. With the current model, one can realistically investigate the effects of all kinds of piston and liner distortion, piston secondary motion, bridging, and lube-oil dilution on gas sealing, oil transport and lubrication. As a result, optimization of the ring designs and the part of block design contributing to bore distortion can be coordinated to reduce development costs.

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.