Dynamic behaviours of piston rings and their practical impact. Part 1: Ring flutter and ring collapse and their effects on gas flow and oil transport

2002 ◽  
Vol 216 (4) ◽  
pp. 209-228 ◽  
Author(s):  
T Tian
Keyword(s):  
Gas Flow ◽  
Great Influence ◽  
Spark Ignition Engine ◽  
Torsional Stiffness ◽  
Critical Parameters ◽  
Oil Consumption ◽  
Piston Rings ◽  
Ring Groove ◽  
Oil Transport ◽  
Heavy Duty Diesel

This paper describes the physics of two major dynamic behaviours of the piston rings, namely ring flutter and ring collapse, and their effects on gas flow and oil transport. The analysis was conducted by applying a theoretical model in a spark ignition engine and a heavy-duty diesel engine. Parameters that have great influence on these dynamic behaviours are discussed for these two different types of engine and different rings. Specifically, the importance of ring twist, torsional stiffness and ring-groove clearance to ring flutter are discussed in detail. For ring radial collapse, the paper presents a simple formula that determines value of the critical parameters to eliminate ring radial collapse. Emphases are placed on the importance of mechanical designs in changing the performance of the piston ring pack in blowby and oil consumption.

Modeling Piston-Ring Dynamics, Blowby, and Ring-Twist Effects

1998 ◽  
Vol 120 (4) ◽  
pp. 843-854 ◽  
Author(s):  
T. Tian ◽  
L. B. Noordzij ◽  
V. W. Wong ◽  
J. B. Heywood
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Great Influence ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Gas Flows ◽  
Ring Groove ◽  
Ring Dynamics ◽  
Low Load ◽  
Groove Configurations

A ring-dynamics and gas-flow model has been developed to study ring/groove contact, blowby, and the influence of ring static twist, keystone ring/groove configurations, and other piston and ring parameters. The model is developed for a ring pack with three rings. The dynamics of the top two rings and the gas pressures in the regions above the oil control ring are simulated. Distributions of oil film thickness and surface roughness on the groove and ring surfaces are assumed in the model to calculate the forces generated by the ring/groove contact. Ring static and dynamic twists are considered, as well as different keystone ring/groove configurations. Ring dynamics and gas flows are coupled in the formulation and an implicit scheme is implemented, enabling the model to resolve detailed events such as ring flutter. Studies on a spark ignition engine found that static twist or, more generally speaking, the relative angle between rings and their grooves, has great influence on ring/groove contact characteristics, ring stability, and blowby. Ring flutter is found to occur for the second ring with a negative static twist under normal operating conditions and for the top ring with a negative static twist under high-speed/low-load operating conditions. Studies on a diesel engine show that different keystone ring/groove configurations result in different twist behaviors of the ring that may affect the wear pattern of the keystone ring running surfaces.

Numerical Study on the Tribological Performance of Ring/Liner System With Consideration of Oil Transport

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Cheng Liu ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Sha Li ◽  
Jianxiong Kang ◽  
...  
Keyword(s):  
Transport Model ◽  
Numerical Study ◽  
Great Influence ◽  
Cylinder Liner ◽  
Tribological Performance ◽  
Oil Consumption ◽  
Oil Supply ◽  
Oil Transport ◽  
Liner System ◽  
Lubrication Condition

The tribological performance of a compression ring-cylinder liner system (CRCL) is numerically studied. A thermal-mixed lubrication model is developed for the lubrication analysis of the CRCL with consideration of the cylinder liner deformation. An oil transport model coupled with a mass conservation cavitation algorithm is employed to predict the oil consumption and the transition between the fully flooded lubrication condition and starved lubrication condition. On this basis, the effects of the oil supply and cylinder liner deformation on the frictional characteristics are investigated under cold and warm engine conditions. The results show that the cylinder liner deformation and oil supply have great influence on the tribological performance of the CRCL. Better tribological performance and lower oil consumption can be obtained by reasonably controlling the oil supply.

The Dynamics of Second Ring Flutter and Collapse in Modern Diesel Engines

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Chao Cheng ◽  
Harold Schock ◽  
Dan Richardson
Keyword(s):  
Diesel Engine ◽  
Gas Flow ◽  
Piston Ring ◽  
Sensitivity Study ◽  
The Other ◽  
Heavy Duty ◽  
Oil Consumption ◽  
Ring Dynamics ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Second ring fluttering and radial ring collapse are recognized as having significant influences on engine blowby and oil consumption. As the gas flow is coupled with the piston ring motion, understanding the ring dynamics is important for understanding not only the engine blowby mechanism, but also oil consumption mechanisms and how to control them. Only second ring flutter and collapse that occurs around the top dead center (TDC) firing conditions is examined in this paper based on a modern heavy-duty diesel engine. However, the principles described are equally applicable to all engines. First, the authors describe the fundamental mechanisms of how second ring fluttering and radial ring collapse occur. This is described by examining the forces that are acting on the second ring. Then, two cases are shown. One case shows second ring flutter and the other case shows stable second ring motion. The reasons for these two different cases are explained, including the effect of static twist and the end gaps of the rings. A sensitivity study was performed to evaluate the effect of changing the top and second ring end gaps on ring lift. It was shown how the gaps could affect the second ring flutter and ring collapse. It is concluded that the second ring will be more likely to flutter or collapse if it has a negative static twist, if the second ring end gap is large, and/or if the top ring end gap is small. If the second ring does not flutter, it may still be possible to design the ring pack such that there is not any reverse blowby. However, this must be carefully studied and controlled or the second land pressures will be too high, resulting in reverse blowby and/or top ring lifting.

The Dynamics of Second Ring Flutter and Collapse in Modern Diesel Engines

2014 ◽  
Author(s):  
Chao Cheng ◽  
Harold Schock ◽  
Dan Richardson
Keyword(s):  
Diesel Engine ◽  
Gas Flow ◽  
Piston Ring ◽  
Sensitivity Study ◽  
The Other ◽  
Heavy Duty ◽  
Oil Consumption ◽  
Ring Dynamics ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Second ring fluttering and radial ring collapse are recognized as having significant influences on engine blowby and oil consumption. As the gas flow is coupled with the piston ring motion, understanding the ring dynamics is important for understanding not only the engine blowby mechanism, but also oil consumption mechanisms and how to control them. Only second ring flutter and collapse that occurs around the top dead center firing conditions is examined in this paper based on a modern heavy-duty diesel engine. However, the principles described are equally applicable to all engines. First, the authors describe the fundamental mechanisms of how second ring fluttering and radial ring collapse occurs. This is described by examining the forces that are acting on the second ring. Then, two cases are shown. One case shows second ring flutter and the other case shows stable second ring motion. The reasons for these two different cases are explained, including the effect of static twist and the end gaps of the rings. A sensitivity study was performed to evaluate the effect of changing the top and second ring end gaps on ring lift. It was shown how the gaps could affect the second ring flutter and ring collapse. It is concluded that the second ring will be more likely to flutter or collapse if it has a negative static twist, if the second ring end gap is large, and/or if the top ring end gap is small. If the second ring does not flutter, it may still be possible to design the ring pack such that there is not any reverse blowby. However, this must be carefully studied and controlled or the second land pressures will be too high, resulting in reverse blowby and/or top ring lifting.

Investigation Techniques of In Situ AlMg/AlN Metal Matrix Composites via Reactive Gas Injection

2013 ◽  
Vol 837 ◽  
pp. 283-289 ◽  
Author(s):  
Raluca Maria Florea ◽  
Oana Bălţătescu ◽  
Aurelian Buzăianu ◽  
Ioan Carcea
Keyword(s):  
Metal Matrix ◽  
Gas Flow ◽  
Sem Analysis ◽  
Critical Parameters ◽  
Matrix Composites ◽  
Uniform Dispersion ◽  
Liquid Systems ◽  
Spontaneous Infiltration ◽  
Reactive Gas

In this paper characteristics of an AlMg/AlN composite produced in-situ and processed in a flowing N2 atmosphere is investigated. Some critical parameters such as the manufacturing process temperature, the percentage of the magnesium consumed, the flowing reactive gas flow and the time for completing the manufacturing are considered as variables for the parametric investigation. Moreover, the effect of different amount of Mg employed has been also investigated, since Mg acts as a catalyst at the surface both for the gas/liquid and solid/liquid systems. Traditional methods were used for the basic characterization of the composite. The microstructure of the composite was investigated by optical and scanning electron microscopy (OM, SEM). SEM analysis was performed in order to observe the microstructural evolution as a function of the Mg content and to identify some reasons of the presence of porosity or any irregularities within the metal matrix. The evolution of mechanical properties, in terms of microhardness, at different percentage of Mg were monitored. By EDS technique the distribution of the elements was obtained. Furthermore, employing an optimization process, uniform dispersion of the strengthening (AlN) particles in the metal matrix with homogeneous properties along the composite material is obtained. Based on the aforementioned statements, it can be concluded that the reactions between Al, Mg and the N2 atmosphere induce spontaneous infiltration in the metal matrix. The complete mix of properties and experimentally assessed parameters can be used for industrial purpose manufacturing design and development.

scholarly journals Usage of the influence coefficient during calculation of a nominal error of gas counters

2019 ◽  
Vol 298 ◽  
pp. 00009
Author(s):  
M.S. Ostapenko ◽  
M.A. Popova ◽  
A.M. Tveryakov
Keyword(s):  
Relative Error ◽  
Gas Flow ◽  
Oil And Gas ◽  
Great Influence ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Influence Coefficient ◽  
Technical Documentation ◽  
Flow Meters ◽  
Influence Coefficients

In this paper, we evaluate the method of finding the relative error of gas flow meters taking into account the influence coefficients. A literature analysis was carried out, which showed that flow meters are used at oil and gas enterprises, which show its metrological characteristic, showing specific values of gas flow in operating conditions. Various types of gas flow meters are considered, with a description of the quality indicators of the devices. An additional error was investigated depending on changes in operating conditions. The calculations of the relative error of the meter taking into account the limiting values of the additional errors indicated in the technical documentation, as well as calculations taking into account the coefficients of influence under operating conditions. Based on the obtained values of the influence coefficients, graphs were constructed on which the effect of temperature and pressure on the error was determined. The article provides tabular values of the influence coefficients for petroleum gas, a conclusion is drawn on the applicability of this method.Oil and gas industry have a great influence on development of national economy in our country. Oil and gas have a leading position in energy industry and they are more effective and energy-intense in comparison with other natural substances.

scholarly journals Critical Parameters and Influence on Dynamic Behaviours of Nonlinear Electrostatic Force in a Micromechanical Vibrating Gyroscope

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shuying Hao ◽  
Yulun Zhu ◽  
Yuhao Song ◽  
Qichang Zhang ◽  
Jingjing Feng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Bias Voltage ◽  
Electrostatic Force ◽  
Dynamic Performance ◽  
Great Influence ◽  
Critical Parameters ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Element Analysis ◽  
Dc Bias

The electrostatic force nonlinearity caused by fringe effects of the microscale comb will affect the dynamic performance of the micromechanical vibrating gyroscopes (MVGs). In order to reveal the influence mechanism, a class of four-degree-of-freedom (4-DOF) electrostatically driven MVG is considered. The influence of DC bias voltage and comb spacing on the nonlinearity of electrostatic force and the dynamic response of the MVG by using multiple time scales method and numerical simulation are discussed. The results indicate that the electrostatic force nonlinearity causes the system to show stiffness softening. The softening characteristics of the electrostatic force cause the offset of the resonance frequency and a decrease in sensitivity. Although the electrostatic nonlinearity has a great influence on the dynamic behaviour, its influence can be avoided by the reasonable design of the comb spacing and DC bias voltage. There exists a critical value for comb spacing and DC bias voltage. In this paper, determining the critical values is demonstrated by nonlinear dynamics analysis. The results can be supported by the finite element analysis and numerical simulation.

Gas Flow Investigation by Stereography in Spark Ignition Engine

1991 ◽  
Author(s):  
Keiji Saneyoshi ◽  
Keiji Hanawa ◽  
Makoto Kaneko ◽  
Haruki Kobayashi
Keyword(s):  
Gas Flow ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Flow Investigation
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