scholarly journals Interring Gas Dynamic Analysis of Piston in a Diesel Engine considering the Thermal Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Wanyou Li ◽  
Yibin Guo ◽  
Tao He ◽  
Xiqun Lu ◽  
Dequan Zou
Keyword(s):  
Gas Dynamics ◽  
Thermal Deformation ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Combustion Engines ◽  
Inverse Heat Conduction ◽  
Piston Head ◽  
Ring Dynamics ◽  
Piston Ring Pack ◽  
Ring Pack

Understanding the interaction between ring dynamics and gas transport in ring pack systems is crucial and needs to be imperatively studied. The present work features detailed interring gas dynamics of piston ring pack behavior in internal combustion engines. The model is developed for a ring pack with four rings. The dynamics of ring pack are simulated. Due to the fact that small changes in geometry of the grooves and lands would have a significant impact on the interring gas dynamics, the thermal deformation of piston has been considered during the ring pack motion analysis in this study. In order to get the temperature distribution of piston head more quickly and accurately, an efficient method utilizing the concept of inverse heat conduction is presented. Moreover, a sensitive analysis based on the analysis of partial regression coefficients is presented to investigate the effect of groove parameters on blowby.

An integrated model for the performance of piston ring pack in internal combustion engines

2017 ◽  
Vol 232 (3) ◽  
pp. 371-384 ◽  
Author(s):  
Kamel G Mahmoud ◽  
Oliver Knaus ◽  
Tigran Parikyan ◽  
Guenter Offner ◽  
Stjepan Sklepic
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Three Dimensional ◽  
Combustion Engines ◽  
Two Dimensional ◽  
Modelling Method ◽  
Ring Dynamics ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Modelling Approach

Piston rings are important components in internal combustion engines. Their primary function is to seal dynamically the gap between moving piston and cylinder liner surface in order to prevent the combustion gases from penetrating into the crankcase. The rings also control the oil leakage from the crankcase to the combustion chamber. The performance of the piston ring pack impacts the engine efficiency, durability and emissions. The recognition of the impact of the ring-pack performance on the engine design resulted in a sustained effort of research and development aimed at understanding the operation of the piston ring pack. Most of the published models developed in this field are two-dimensional assuming that the ring and liner are perfect circles for the purpose of modelling the axial and radial dynamics. Although this approach has proved to be useful, there exist a number of asymmetrical characteristics of the power cylinder system that can be crucial to the ring-pack performance and therefore it is considered to be appropriate. In this work, an integrated methodology that handles the complex ring-pack mechanism is presented. The physics of the ring-pack mechanism covers the three-dimensional piston ring dynamics of asymmetric engine cylinder due to bore distortion, the mixed lubrication at ring running face as well as the ring flanks and the interring gas dynamics. The modelling method is verified in two steps. In the first step, the dynamic behaviour of the three-dimensional ring model is verified against a commercial finite element software by comparing the eigenmodes up to a frequency of about 1 kHz. In the second step, the ring-pack modelling approach using three-dimensional ring models is also verified against a commercial ring dynamics program, which is based on the two-dimensional modelling. It is shown that the three-dimensional ring dynamics modelling method has advantages over the two-dimensional modelling approach as it facilitates studying the influence of the non-uniform twist along its circumference (ring winding), the effect of bore distortion on blow-by, ring friction, friction power losses and wear.

An Integrated Model of Ring Pack Performance

1991 ◽  
Vol 113 (3) ◽  
pp. 382-389 ◽  
Author(s):  
R. Keribar ◽  
Z. Dursunkaya ◽  
M. F. Flemming
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Engine Speed ◽  
Integrated Model ◽  
Design Parameters ◽  
Combustion Engines ◽  
Predictive Tool ◽  
Engine Friction ◽  
Piston Ring Pack ◽  
Ring Pack

This paper describes an integrated model developed for the detailed characterization and simulation of piston ring pack behavior in internal combustion engines and the prediction of ring pack performance. The model includes comprehensive and coupled treatments of (1) ring-liner hydrodynamic and boundary lubrication and friction; (2) ring axial, radial, and (toroidal) twist dynamics; (3) inter-ring gas dynamics and blowby. The physics of each of these highly inter-related phenomena are represented by submodels, which are intimately coupled to form a design-oriented predictive tool aimed at the calculation of ring film thicknesses, ring motions, land pressures, engine friction, and blowby. The paper also describes the results of a series of analytical studies investigating effects of engine speed and load and ring pack design parameters, on ring motions, film thicknesses, and inter-ring pressures, as well as ring friction and blowby.

Computer Simulation of the Behavior of the Piston Ring Pack of Internal Combustion Engines

2016 ◽  
Vol 821 ◽  
pp. 166-171
Author(s):  
Peter Raffai ◽  
Pavel Novotný ◽  
Jozef Dlugoš
Keyword(s):  
Computer Simulation ◽  
Research And Development ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Internal Combustion ◽  
Optimization Process ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Piston Ring Pack ◽  
Ring Pack

The continuously tightening regulations limiting the amount of exhaust gas components of internal combustion engines force the manufacturers to further increase the effectivity of their power units. Due to the already relatively highly-developed state of engines result in the need of research and development of even smaller engine parts – e.g. piston rings. The main aim of this project was to develop a tool for the computer simulation of the behavior of the piston ring pack, which could aid the optimization process of the piston ring pack towards lowered friction losses.

Characterization of the Ring Pack Lubricant and its Environment

1995 ◽  
Vol 209 (2) ◽  
pp. 109-118 ◽  
Author(s):  
P J Burnett ◽  
B Bull ◽  
R J Wetton
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Combustion Engines ◽  
Oil Consumption ◽  
Ring Groove ◽  
Direct Sampling ◽  
Engine Wear ◽  
Ring Pack ◽  
Motion Characterization

The performance characteristics of the piston ring-liner assembly and the lubricant within it are critical for the operation of modern internal combustion engines. The ring pack can directly affect engine friction, oil consumption and oil degradation, which in turn can impact upon fuel economy, emissions and engine wear. The operation of this system is complex and no single technique is capable of fully characterizing the processes occurring. This paper outlines the range of both experimental and theoretical methods that are being applied to the study of this system and the lubricant within it. These include the modelling of ring pack gas and oil flows, and direct measurement of piston temperatures, ring belt pressures and piston ring motion. Characterization of lubricant degradation via direct sampling of oil from the top ring groove of an operating engine has also been used. The merits of such a multi-faceted approach are discussed in relation to piston deposit formation.

An analytical study of tribological parameters between piston ring and cylinder liner in internal combustion engines

2016 ◽  
Vol 230 (4) ◽  
pp. 329-349 ◽  
Author(s):  
Mohamed Kamal Ahmed Ali ◽  
Hou Xianjun ◽  
Richard Fiifi Turkson ◽  
Muhammad Ezzat
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Combustion Engines ◽  
Oil Viscosity ◽  
Oil Film ◽  
Ring Assembly ◽  
Ring Dynamics ◽  
Tribological Parameters

This paper presents a model to study the effect of piston ring dynamics on basic tribological parameters that affect the performance of internal combustion engines by using dynamics analysis software (AVL Excite Designer). The paramount tribological parameters include friction force, frictional power losses, and oil film thickness of piston ring assembly. The piston and rings assembly is one of the highest mechanically loaded components in engines. Relevant literature reports that the piston ring assembly accounts for 40% to 50% of the frictional losses, making it imperative for the piston ring dynamics to be understood thoroughly. This analytical study of the piston ring dynamics describes the significant correlation between the tribological parameters of piston and rings assembly and the performance of engines. The model was able to predict the effects of engine speed and oil viscosity on asperity and hydrodynamic friction forces, power losses, oil film thickness and lube oil consumption. This model of mixed film lubrication of piston rings is based on the hydrodynamic action described by Reynolds equation and dry contact action as described by the Greenwood–Tripp rough surface asperity contact model. The results in the current analysis demonstrated that engine speed and oil viscosity had a remarkable effect on oil film thickness and hydrodynamic friction between the rings and cylinder liner. Hence, the mixed lubrication model, which unifies the lubricant flow under different ring–liner gaps, is needed via the balance between the hydrodynamic and boundary lubrication modes to obtain minimum friction between rings and liner and to ultimately help in improving the performance of engines.

scholarly journals Engine Speed and Load on the Sealing Capacity of a Piston Ring-Pack

2020 ◽  
Vol 5 (3) ◽  
pp. 304-313
Author(s):  
Erjon Selmani ◽  
Arian Bisha
Keyword(s):  
Gas Dynamics ◽  
Gas Flow ◽  
Piston Ring ◽  
Engine Speed ◽  
Fuel Mixture ◽  
Sealing Capacity ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Two Parameters ◽  
Gas Pressures

The combustion chamber is ought to be perfectly sealed, however, part of the air and fuel mixture can escape from it. Among the several losses there is the gas flow from the inter-ring crevices, which is always present. This leakage is known as blow-by, and affects efficiency, correct lubrication and emissions. The amount of leakage is dependent on many factors, and among the most important are the engine speed and load, which are able to affect the system through the forces applied on it. The aim of this paper was to understand in a more detailed way how the engine speed and load could affect the sealing efficiency of a ring-pack. For this purpose, a complete range of speeds and loads were used in the simulations. The equations of the ring motions and gas dynamics has been implemented and solved in ©Ricardo RINGPAK solver. The results showed that inertia and inter-ring gas pressures drives the sealing behavior of the rings. The blow-by trend showed to decrease with the speed and increase with the load, exception made for the idle condition where the values were different to the other cases, especially at higher speeds. Among the two parameters, the engine speed resulted to affect more significantly the blow-by trend.

Predictive tool for frictional performance of piston ring-pack/liner conjunction

2019 ◽  
Vol 13 (3) ◽  
pp. 5513-5527
Author(s):  
J. W. Tee ◽  
S. H. Hamdan ◽  
W. W. F. Chong
Keyword(s):  
Film Thickness ◽  
Mathematical Models ◽  
Piston Ring ◽  
Published Data ◽  
Predictive Tool ◽  
Frictional Losses ◽  
Fundamental Understanding ◽  
Minimum Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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