Three-Dimensional Analysis of Tribological Performance and Heat Transfer in Piston and Cylinder Liner System

2003 ◽  
Author(s):  
Xiaoming Ye ◽  
Guohua Chen ◽  
Maji Luo ◽  
Yankun Jiang
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Piston Ring ◽  
Three Dimensional ◽  
Cylinder Liner ◽  
Ring Groove ◽  
Friction Heat ◽  
Liner System ◽  
Piston Ring Pack ◽  
Ring Pack

A three-dimensional, hydrodynamic mixed lubrication model has been developed to investigate the frictional performance of piston ring and cylinder liner contact. The model is based on the average Reynolds equation and asperity contact approach with the considerations of surface roughness, rupture location, blowby through the piston ring pack and nonaxisymmetry in circumferential direction of cylinder liner. The equation has been solved cyclically using the finite difference method in a fully flooded inlet boundary condition and a flow-continuity Reynolds boundary condition for cavitation outlet zone. The oil film thickness, hydrodynamic pressure distribution, friction force and friction heat generated at the piston ring/cylinder liner interface are determined as the function of crank angle position. The results show that the shape of the cylinder liner (out-of-roundness) significantly affects the lubrication performance of the piston ring pack. A heat transfer model has been presented to evaluate the effects of friction heat on the temperatures of piston and cylinder liner system. The friction heat is added on the piston ring/cylinder liner interface as the flux boundary condition. The temperature fields of piston and cylinder liner system are acquired by the FEM, which reveal the distribution of the friction heat in this system. The results show that the friction heat mainly affects the temperature on the region near the top ring groove of the piston ring pack. The effect decreases at the region away from the top ring groove, especially at the piston skirt. The effect of friction heat on the temperature of cylinder liner is smaller than that of piston ring pack.

Transient Heat Transfer Simulation of the Coupling 3-D Moving Piston Assembly-Lubricant Film-Liner System

2006 ◽  
Author(s):  
Liu Zhien ◽  
Jiang Yankun ◽  
Chen Guohua ◽  
Yang Wanli
Keyword(s):  
Heat Transfer ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Heat Transfer Model ◽  
Lubricant Film ◽  
Transient Heat Transfer ◽  
Transfer Model ◽  
Friction Heat ◽  
Liner System ◽  
Piston Assembly

Transient heat transfer model of the coupling 3-D moving piston assembly-lubricant film-liner system is successfully developed for predicting the temperature distributions in the component system of internal combustion chamber, in which the effect of the friction heat generated at the piston ring/cylinder liner interfaces has been taken into account. The finite element method (FEM) is employed in the model for establishing the heat transfer relation among the moving piston assembly-lubricant film-cylinder liner. The 3-D discrete model of the coupling system is obtained by hypothesizing the lubricant film as 1-D thermal resistances and the friction heat as heat flux boundary conditions. The allocation and distribution model of friction heat on piston ring pack and liner are also established. The 3-D coupling heat transfer model has been used to analyze the heat transfer of a gasoline engine.

Modeling and prediction of the running-in behavior of the piston ring pack system based on the stochastic surface roughness

2019 ◽  
Vol 233 (12) ◽  
pp. 1857-1877
Author(s):  
Chunxing Gu ◽  
Di Zhang
Keyword(s):  
Piston Ring ◽  
Transport Model ◽  
Hydrodynamic Pressure ◽  
Cylinder Liner ◽  
Numerical Approach ◽  
Height Distribution ◽  
Asperity Height ◽  
Liner System ◽  
Piston Ring Pack ◽  
Ring Pack

This paper proposes an efficient numerical approach to predict the initial running-in process of piston ring pack/cylinder liner system. A combined mixed lubrication and wear model coupled with an oil transport model was developed. In order to predict the hydrodynamic pressure efficiently, two improved methodologies, including the Fischer-Burmsister-Newton-Schur (FBNS) approach and the Grid Refinement (GR) strategy, were adopted. Meanwhile, in order to take into account the effect of skewness, Weibull distribution function was adopted to characterize the asperity height distribution. Predicting the wear of cylinder liner was based on the Archard's wear law. The influences of asperity plastic deformation and wear on asperity height distribution were considered. The results show that the developed model can well predict the initial running-in behavior of piston ring pack/cylinder liner system under an engine-like condition.

Analyzing the Effects of Three-Dimensional Cylinder Liner Surface Texture on Ring-Pack Performance With a Focus on Honing Groove Cross-Hatch Angle

2005 ◽  
Author(s):  
Jeffrey Jocsak ◽  
Yong Li ◽  
Tian Tian ◽  
Victor W. Wong
Keyword(s):  
Piston Ring ◽  
Three Dimensional ◽  
Cylinder Liner ◽  
Stress Factors ◽  
Asperity Contact ◽  
Oil Consumption ◽  
Surface Textures ◽  
Liner Surface ◽  
Piston Ring Pack ◽  
Ring Pack

Frictional losses in the piston ring-pack of an engine account for approximately 20% of the total frictional losses within an engine. Although many non-conventional cylinder liner finishes are now being developed to reduce friction and oil consumption, the effects of the surface finish on ring-pack performance is not well understood. The current study focuses on modeling the effects of three-dimensional cylinder liner surface anisotropy on piston ring-pack performance. A rough surface flow simulation program was developed to generate flow factors and shear stress factors for three-dimensional cylinder liner surface textures. Rough surface contact between the ring and liner was modeled using a previously published methodology for asperity contact pressure estimation between actual rough surfaces. The surface specific flow factors, shear stress factors, and asperity contact model were used in conjunction with MIT’s previously developed ring-pack simulation program to predict the effects of different surface textures on ring-pack behavior. Specific attention was given to the effect of honing groove cross-hatch angle on piston ring-pack friction in a stationary natural gas engine application, and adverse effects on engine oil consumption and durability were also briefly considered. The modeling results suggest that ring-pack friction reduction is possible if the liner honing cross hatch angle is decreased by reducing the feed-to-speed ratio of the honing tool. Reducing the cross-hatch angle increased oil flow blockage and increased the lubricant’s effective viscosity during mixed lubrication. This allowed more load to be supported by hydrodynamic pressure, reducing ring-pack friction. However, there appeared to be a potential for increased oil consumption and scuffing tendency corresponding to a decrease in honing cross-hatch angle.

Modeling Oil Evaporation From the Engine Cylinder Liner With Consideration of the Transport of Oil Species Along the Liner

2005 ◽  
Author(s):  
Liang Liu ◽  
Tian Tian ◽  
Ertan Yilmaz
Keyword(s):  
Piston Ring ◽  
Gasoline Engine ◽  
Cylinder Liner ◽  
Oil Composition ◽  
Evaporation Model ◽  
Engine Cylinder ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Model Oil ◽  
Engine Cylinder Liner

To estimate oil evaporation from an engine cylinder liner, an evaporation model has been implemented and incorporated with an existing 3-D piston ring-pack lubrication model. In this evaporation model, oil is modeled as being composed of distinct hydrocarbon species. Due to the depletion of light species and temperature variation, oil composition changes with space and time. Great emphasis was placed on the change of oil composition caused by oil transport through the ring-pack movement along the liner. The model was applied to a gasoline engine, and it was demonstrated that due to the movement of piston ring-pack, oil can be transported from the lower liner region to the upper liner region during the compression stroke, which gives a continuous supply of light species for oil evaporation.

The Effects of Cylinder Liner Finish on Piston Ring-Pack Friction

2004 ◽  
Author(s):  
Jeffrey Jocsak ◽  
Victor W. Wong ◽  
Tian Tian
Keyword(s):  
Surface Roughness ◽  
Probability Density ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Probability Density Functions ◽  
Density Functions ◽  
Asperity Contact ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Non Gaussian

This paper presents enhancements to a previously developed mixed-lubrication ring-pack model that has been used extensively in the automotive industry in predicting piston-ring/liner oil film thickness, friction and oil-transport processes along the liner. The previous model considers three lubrication regimes, shear thinning of the lubricant, and the unsteady wetting conditions of the rings at the leading and trailing edges. The model incorporates the effects of surface roughness by using Patir and Cheng’s average flow model and the Greenwood and Tripp statistical asperity contact model, assuming a Gaussian distribution of surface roughness. However, as a result of the methods used to machine a cylinder liner and the wear-in process observed in engines, the cylinder liner finish is highly non-Gaussian. The purpose of this current study is to understand the effects of additional surface parameters other than Gaussian root-mean-square surface roughness on piston ring-pack friction in the context of a natural gas reciprocating engine ring/liner interface. In general, the surface roughness of a cylinder liner is negatively skewed. Applying similar methodology published in the literature, a wide variety of non-Gaussian probability density functions were generated in terms of the skewness of the cylinder liner surface. These probability density functions were implemented into the Greenwood and Tripp asperity contact model, and subsequently into the traditional MIT ring-pack friction model. The effects of surface skewness on flow were approximated using Gaussian flow factors and a simple truncation method. The enhanced model was studied in conjunction with results from an existing ring-pack dynamic model that provided the dynamic twists of the rings relative to the liner and inter-ring pressures. In this manner, a detailed analysis of the effects of engineered cylinder liner finish on reducing friction losses was performed.

A Three-Dimensional Model for Piston Ring-Pack Dynamics and Blow-By Gas Flow

2004 ◽  
Author(s):  
Liang Liu ◽  
Tian Tian
Keyword(s):  
Dynamic Behavior ◽  
Gas Flow ◽  
Piston Ring ◽  
Three Dimensional ◽  
Beam Theory ◽  
Ring Structure ◽  
Three Dimensional Model ◽  
Secondary Motion ◽  
Piston Ring Pack ◽  
Ring Pack

A three-dimensional (3D) model for piston ring-pack dynamics and blow-by gas flow was developed to enable more in-depth analyses of the ring-pack performance. This model predicts the 3D dynamic behavior of compression rings and twin-land oil control ring due to the ring’s non-axisymmetric properties, bore distortion and piston secondary motion. Finite element beam theory is used for ring structure calculation. Gas flows along the axial and circumferential directions of the power cylinder system are resolved simultaneously with the ring dynamics. The model was applied to a heavy-duty diesel engine. Particular emphasis was placed on the dynamics of keystone type of top ring, and the stability of the second ring with a twist chamfer and twin-land oil control ring under the influence of piston secondary motion. The variations of the gas pressure and ring dynamic behavior along the circumference are discussed.

scholarly journals Numerical analysis of piston ring pack operation

2009 ◽  
Vol 137 (2) ◽  
pp. 128-141
Author(s):  
Andrzej WOLFF
Keyword(s):  
Mathematical Model ◽  
Gas Flow ◽  
Piston Ring ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Labyrinth Seal ◽  
Piston Rings ◽  
Oil Film ◽  
Piston Ring Pack ◽  
Ring Pack

In the paper a model of a piston ring pack motion on an oil film has been analysed. The local oil film thickness can be compared to height of the combined roughness of mating surfaces of piston rings and cylinder liner. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng [6, 7] and Greenwood, Tripp [3] have been combined [12] and used in this paper. A model of a gas flow through the labyrinth seal of piston rings has been developed [13, 15]. In addition models of ring twist effects and axial ring motion in piston grooves have been applied [14, 15]. In contrast to the previous papers of the author, an experimental verification of the main parts of developed mathematical model and software has been presented. A relatively good compatibility between the experimental measurements and calculated results has been achieved. In addition this study presents the simulation results for an automobile internal combustion engine

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.

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