The only paper that can be traced on this subject so far is Mr. Nakagawa's report on the determination of the relative distribution of pressure on the cylinder wall, but the measuring method adopted therein appears to need further consideration. No exact idea has yet been obtained as to how the obturation of gas between the piston and cylinder, the frictional resistance of the piston , and the wear of the cylinder wall are affected by the intensity and the distribution of the radial pressure of the piston ring.
Consequently, the author has endeavored, by employing an apparatus of his own invention, to get an exact determination of the pressure distribution of the piston ring. By means of a newly devised ring tester, to which piezoelectricity of quartz was applied, the distribution of the radial pressure of many sample rings on the market was accurately determined. Since many famous piston rings show very irregular pressure distribution, the author investigated and achieved a manufacturing process of the piston ring which will exert uniform pressure on the cylinder wall.
Temperature effects on the configuration and on the mean spring power have also been studied.
Further, the tests were performed to ascertain how the gas tightness of the piston ring may be affected by the number or spring power. The researches as to the frictional resistance between the piston ring and the cylinder wall were carried out, too. The procedure of study, and. A good tribological description for the cylinder liner and piston ring materials is always desired in order to achieve an improved combination of the materials.
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The piston ring package in a two-stroke-diesel engine operates in three lubrication regimes and the materials must be characterized A tribo-test-apparatus is developed to study the tribological performance and to rank the different combinations of cylinder liner and piston ring materials of two stroke marine diesel engines. The test apparatus is based on the block-on- ring principle Integral Ring Carbon-Carbon Piston. An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed.
An integral ring carbon-carbon composite piston , disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.
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Double acting stirling engine piston ring. Full Text Available This article describes, develops and applies approach of the interaction of rough surfaces for one of the tasks of simulation of tribological systems of the piston engine. In this paper we described the general approach to building a model of interaction between rough surfaces, leading to the analysis of the Markov process. Given the initial data and the method of calculating the trajectory of movable elements on the lubricating layer, we determined the tribological parameters defining the service life of tribological systems of the piston engine on the example of crankshaft bearings.
Investigation of friction characteristics in segmented piston ring liner assembly of IC engine. New materials, coatings and high-tech machining processes that previously were considered to be too expensive and therefore only used in complex applications are today becoming more affordable.
A significant amount of the total power loss in a modern automotive engine is due to the Friction interaction between the top compression ring and the cylinder liner, especially at the TDC and BDC where boundary lubrication exists.
The change in piston speed is accompanied with change the lubrication regime in the cylinder, which results change in friction between the ring and the liner during the entire stroke of the piston. Theoretical modelling of friction force from the various sources of friction will be compared to experimental results for analysing the tribological characteristics. The appropriate sample of piston ring and cylinder liner pair is developed for studying the different tribological parameters on Reciprocating Tribometer.
The variable parameters are engine speed, oil viscosity, and load. It can be seen that as speed increases, the friction force and friction coefficient also decreases. Full Text Available The friction pair of piston rings and cylinder liner is one of the most important friction couplings in an internal combustion engine.
It influences engine efficiency and service life. Under the excitation of piston slaps, the dynamic deformation of cylinder liner is close to the surface roughness magnitudes, which can affect the friction and lubrication performance between the piston rings and cylinder assemblies.
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To investigate the potential influences of structural deformations to tribological behaviours of cylinder assemblies, the dynamic deformation of the inner surface due to pistons slaps is obtained by dynamic simulations, and then coupled into an improved lubrication model. Different from the traditional lubrication model which takes the pressure stress factor and shear stress factor to be constant, the model proposed in this paper calculated these factors in real time using numerical integration to achieve a more realistic simulation.
Based on the improved piston rings and cylinder liner lubrication model, the minimum oil film thickness and friction force curves are obtained for an entire work cycle.
It shows that the friction force obtained from the improved model manifests clear oscillations in each stoke, which is different from the smoothed profiles predicted traditionally. Moreover, the average amplitude of the friction forces also shows clear reduction. Piston ring lubrication and hydrocarbon emissions from internal combustion engines.
Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model.
This implies the development of a ring -pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally.
Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine.
Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system MBS. Full Text Available This paper presents a mathematical model of piston-rings -cylinder sealing TPC of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit, displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner.
Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls, were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model, the model itself, its numerical solution as well as its computer application for carrying out simulation tests. Translational velocity oscillations of piston generated vortex rings. Experimental results are presented that show that the translational velocities of piston generated vortex rings often undergo oscillations, similar to those recently discovered for drop generated rings.
An attempt has been made to minimize uncertainties by utilizing both dye and hydrogen bubbles for visualization and carefully repeating measurements on the same ring and on different realizations under the same nominal piston conditions. The results unambiguously show that under most conditions, both for laminar and turbulent rings and for rings generated from pipes and orifices, the oscillations are present.
The present results, together with the earlier results on drop generated rings , give support to the view that translational velocity oscillations are probably an inherent feature of translating vortex ring fields. Fluorocarbon seal replaces metal piston ring in low density gas environment. Reinforced fluorocarbon cupseal, which provides an integral lip-type seal, replaces the metal piston rings in piston -cylinder configurations used in the compression of low density gases. The fluorocarbon seal may be used as cryogenic compressor piston seals. Full Text Available Tribological parameters such as friction, lubrication and wear influence strongly the engine component's life.
In this study, a piston ring -cylinder system simulated taking into account the surface modifications under fully flooded lubrication and normal engine conditions.
The hydrodynamic pressure field solved based on the Navier Stokes equations by Fluid Structure Interaction analysis. A real experimental data of piston ring -cylinder was used from a two stroke motor engine 50 cc. The surface irregularities are measured by 3D coordinate measurement machine while the engine has been worked about hours. The friction force, the hydrodynamic pressure, the oil film and the mechanical stresses were predicted for different engine conditions. Results show that the worn profile ring reduces the friction as well as the mechanical stresses increased.
Surface condition of worn top ring was observed after a metallurgical profile analysis. Investigation of piston ring — cylinder liner dry wear using a block-on- ring test rig.
Characterization of the wear of piston rings and cylinder liner is an important aspect of large two stroke diesel engine design. Two major wear mechanisms exist; corrosive wear and mechanical wear. This paper deals with the most aggressive form of the latter, which is known as scuffing.
The highlighting of an internal combustion engine piston ring radial oscillations. Full Text Available This paper deals with the definition of the lube-oil film thickness in the piston ring cylinder liner junction of an internal combustion engine. At first, a mathematical model for the estimation of the film thickness is established.
It is used to point out the oscillating motion of the piston ring normal to the cylinder wall. For the first time, has been highlighted and analytically evaluated the oscillating behavior of the piston ring in its housing in the radial direction. Furthermore, it is demonstrated that the radial oscillations frequency is a function of piston ring stiffness, material and geometry.
Piston rings are vital components of any internal combustion engine, and their performance affect important properties such as frictional losses, oil consumption, and wear of parts. This thesis deals with the lubrication of piston rings from a theoretical point of view. Predictions are made using Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases.
The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear.
The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring , geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation.
The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre. A theoretical investigation of the hydrodynamic lubrication of the top compression piston ring in a large two-stroke marine diesel engine is presented. The groove mounted piston ring is driven by the reciprocal motion of the piston. The ring shape follows a circular geometry and the effect Investigation of different piston ring curvatures on lubricant transport along cylinder liner in large two-stroke marine diesel engines.
We report molecular dynamics experiments with ideal gas particles and show that they can exchange energy with their container.