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.

Gas flow through the piston ring pack

2018 ◽  
Author(s):  
Petr Veigend ◽  
Gabriela Necasov ◽  
Peter Raffai ◽  
Vclav Åtek ◽  
Jir Kunovsk
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Flow Through ◽  
Piston Ring Pack ◽  
Ring Pack

Detailed analysis of piston secondary motion and tribological performance

2019 ◽  
Vol 21 (9) ◽  
pp. 1647-1661 ◽  
Author(s):  
Cristiana Delprete ◽  
Abbas Razavykia ◽  
Paolo Baldissera
Keyword(s):  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Tribological Performance ◽  
System Of Nonlinear Equations ◽  
Piston Skirt ◽  
Wide Range ◽  
Secondary Motion ◽  
Piston Ring Pack ◽  
Ring Pack

This article presents a detailed analytical model to evaluate piston skirt tribology under hydrodynamic lubrication. The contribution of the piston ring pack lubrication has been taken into account to study piston secondary motion and tribological performance. A system of nonlinear equations comprising Reynolds equation and force equilibrium is solved to calculate piston ring pack friction force and its moment about wrist pin axis. Instantaneous minimum oil film thickness at piston ring/liner interface has been estimated considering different boundary conditions: full Sommerfeld, oil separation, and Reynolds cavitation and reformation. The ring pack model has capability to be used for a wide range of ring face profiles under boundary and hydrodynamic lubrication. Piston secondary motion is evaluated using lubrication theory and equilibrium of forces and moments, to examine the effect of wrist pin location, piston skirt/liner clearance, and oil rheology. Numerical method and finite difference scheme have been used to define piston eccentricity and hydrodynamic pressure acting over the skirt.

A study of the influences of particles in the gas flow passage of a piston ring pack on the tribological performances of the piston ring

2009 ◽  
Vol 224 (1) ◽  
pp. 201-215 ◽  
Author(s):  
F-M Meng ◽  
J-X Wang ◽  
K Xiao
Keyword(s):  
Friction Force ◽  
Gas Flow ◽  
Piston Ring ◽  
Maximum Shear Stress ◽  
Gas Pressure ◽  
Von Mises Stress ◽  
Flow Passage ◽  
Particle Effect ◽  
Piston Ring Pack ◽  
Ring Pack

The influences of particles in the gas flow passage of a piston ring pack on the tribolo-gical performances of rings were numerically investigated based on a modified blow-by equation incorporating the particle effect and associated equations. Meanwhile, the particle effect on the blow-by of rings, inter-ring gas pressure, friction force, stresses, pressure, and deformation of the ring was solved by the Runge—Kutta method and the fast Fourier transform (FFT) technique. The numerical results show that obvious changes in the blow-by of the ring and the inter-ring gas pressure can occur if the particle effect is considered. The effect depends on the combined effect of the area, position, and number of particles. Meanwhile, the friction force of the top face of the ring, and the maximum Von Mises stress of the inner ring surface, contact pressure, deformation, and maximum shear stress of the contacting surface of the ring can obviously increase because of the particle effect.

Computer Program Development Predicting Engine Oil Consumption

2005 ◽  
Author(s):  
Sang Myung Chun
Keyword(s):  
Computer Program ◽  
Gas Flow ◽  
Piston Ring ◽  
Engine Performance ◽  
Engine Oil ◽  
Optimized Design ◽  
Oil Consumption ◽  
Piston Cylinder ◽  
Piston Ring Pack ◽  
Ring Pack

The oil consumption and blow-by gas through piston-cylinder-ring crevices have to be minimized. Meanwhile, the friction losses in the piston ring pack need to be reduced in order to improve fuel economy and engine performance. In these two aspects, study on the optimized design of the piston ring pack has to be carried out. The amounts of oil consumption and blow-by gas are important factors to decide whether an engine is operating under good conditions or not during engine development and engine life cycle. The purpose of this study is to develop a computer program predicting engine oil consumption and blow-by gas by calculating the amount of oil flowing into the combustion chamber and gas flow down to the crankcase through the piston ring pack. Using this program, the condition of an engine can be predicted in advance.

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

Two-dimensional lubrication study of the piston ring pack

1998 ◽  
Vol 212 (3) ◽  
pp. 215-220 ◽  
Author(s):  
K Liu ◽  
Y. B. Xie ◽  
C. L. Gui
Keyword(s):  
Film Thickness ◽  
Piston Ring ◽  
Cylinder Wall ◽  
Asperity Contact ◽  
Two Dimensional ◽  
Oil Film ◽  
Secondary Motion ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Piston Ring Lubrication

Based on the two-dimensional average flow model and asperity contact model, a theoretical model for the non-axisymmetrical analysis of piston ring lubrication has been suggested in this paper. The two-dimensional distribution of oil-film thickness between the piston rings and cylinder wall is obtained. Results show that the oil-film thickness along the circumference is non-uniform. Starvation is also considered in the model. The effect of secondary motion of piston assemblies on the lubrication property of the piston ring pack has also been studied.

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.

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.

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