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Modeling of Liner Finish Effects on Oil Control Ring Lubrication in Internal Combustion Engines Based on Deterministic Method

2008
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Release : 2008
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Book Synopsis Modeling of Liner Finish Effects on Oil Control Ring Lubrication in Internal Combustion Engines Based on Deterministic Method by : Haijie Chen

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. This book was released on 2008. 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.

Modeling the Lubrication of the Piston Ring Pack in Internal Combustion Engines Using the Deterministic Method

2011
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Release : 2011
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Book Synopsis Modeling the Lubrication of the Piston Ring Pack in Internal Combustion Engines Using the Deterministic Method by : Haijie Chen

Download or read book Modeling the Lubrication of the Piston Ring Pack in Internal Combustion Engines Using the Deterministic Method written by Haijie Chen. This book was released on 2011. 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.

Developing an Approach Utilizing Local Deterministic Analysis to Predict the Cycle Friction of the Piston Ring-pack in Internal Combustion Engines

2013
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Release : 2013
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Book Synopsis Developing an Approach Utilizing Local Deterministic Analysis to Predict the Cycle Friction of the Piston Ring-pack in Internal Combustion Engines by : Yang Liu (S.M.)

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.). This book was released on 2013. 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.

Modeling of Contact Between Liner Finish and Piston Ring in Internal Combustion Engines Based on 3D Measured Surface

2014
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Release : 2014
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Book Synopsis Modeling of Contact Between Liner Finish and Piston Ring in Internal Combustion Engines Based on 3D Measured Surface by : Qing Zhao (S.M.)

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.). This book was released on 2014. 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.

Modeling the Effects of Liner Pores on Piston Ring Lubrication in Internal Combustion Engines

2019
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Release : 2019
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Book Synopsis Modeling the Effects of Liner Pores on Piston Ring Lubrication in Internal Combustion Engines by : Jérôme Sacherer

Download or read book Modeling the Effects of Liner Pores on Piston Ring Lubrication in Internal Combustion Engines written by Jérôme Sacherer. This book was released on 2019. 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.

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