Modeling of Gas Pressure and Dynamic Behavior of the Piston Ring Pack for the Two-Stroke Opposed-Piston Engine

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Wen-Bin Chen ◽  
De-Liang Liu ◽  
Jiu-Jun Xu ◽  
Ruo-Xuan Huang ◽  
Ze-Zhong Chen ◽  
...  
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Engine Speed ◽  
Gas Pressure ◽  
Piston Engine ◽  
Continuity Equations ◽  
Force Equation ◽  
Axial Movement ◽  
Piston Ring Pack ◽  
Ring Pack

The piston ring pack and the ports on the cylinder linear wall have a great impact on the performance of the two-stroke opposed-piston engine. In this work, a piston ring pack model for this type of engine was generated to incorporate the exhaust ports. The effect of the exhaust ports was considered by modifying the existing friction force equation and the gas flow continuity equations. The developed model was implemented in an opposed-piston opposed-cylinder engine (a specific type of opposed-piston engine) to investigate the backpressure and the associated axial movement of all the rings of the piston ring pack under various working conditions. The results show that the gas pressure in all the regions of the piston ring pack and the axial movement of the rings are strongly affected by the exhaust ports. The gas pressure in some regions of the ring pack declines with the increase of the engine speed, while the effect of the combustion pressure (CP) on the axial movement of the ring pack can be neglected.

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.

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.

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

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 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.

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

scholarly journals Influence of piston ring pack configuration on blowby and friction losses in a marine two-stroke engine

2017 ◽  
Vol 170 (3) ◽  
pp. 164-170
Author(s):  
Andrzej WOLFF
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Labyrinth Seal ◽  
Piston Rings ◽  
Marine Engine ◽  
Oil Film ◽  
Flow Through ◽  
Piston Ring Pack ◽  
Ring Pack

In the paper a comprehensive model of a piston ring pack motion on an oil film has been presented. The local thickness of the oil film can be compared to height of the combined surface roughness of a cylinder liner and piston rings. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been combined and used in this paper. In addition a model of gas flow through the labyrinth seal of piston rings has been developed. The main parts of the model and software have been experimentally verified abroad by the author at the marine engine designing centre. For the selected two-stroke marine engine, the influence of the number of piston rings used and the type of the top ring lock (straight or overlapped) on blowby to piston underside and on friction losses of the piston-ring-cylinder (PRC) system have been investigated. The developed model and software can be useful for optimization of the PRC system design

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