Challenges Involved in Piston Top Ring Designs for Modern SI Engines

2000 ◽  
Vol 123 (2) ◽  
pp. 448-459 ◽  
Author(s):  
R. Rabute´ ◽  
T. Tian
Keyword(s):  
Piston Ring ◽  
Engine Test ◽  
Environment Protection ◽  
Oil Consumption ◽  
Potential Influence ◽  
Ring Groove ◽  
Higher Power ◽  
Si Engines ◽  
Engine Components ◽  
Component Temperature

Driven by energy conservation and environment protection, modern SI engines are required to have higher and higher power density. Consequently, engines and engine components are becoming tighter and lighter, and engines are more often operated at elevated speed and component temperature. Piston and piston ring designs thus face constant challenge to provide proper control of blow-by, oil consumption, friction, wear, and oil consumption. This paper is intended to give an overview of the problems associated with top ring performance in modern SI engines, the mechanisms behind these problems, and possible solutions. The analysis is based on engine test data and computer models. Major topics covered in this paper include (1) top ring flutter and collapse, and their influence on blow-by; (2) top ring reverse flutter and its influence on oil consumption; (3) contact between top ring and its groove, and its potential influence on ring/groove wear and micro-welding; (4) top ring/liner lubrication and its influence on ring face friction, wear, and scuffing.

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.

Effects of Piston-Ring Dynamics on Ring/Groove Wear and Oil Consumption in a Diesel Engine

1997 ◽  
Author(s):  
Tian Tian ◽  
Remi Rabute ◽  
Victor W. Wong ◽  
John B. Heywood
Keyword(s):  
Diesel Engine ◽  
Piston Ring ◽  
Oil Consumption ◽  
Ring Groove ◽  
Ring Dynamics

Understanding the Fundamentals of Piston Ring Axial Motion and Twist and the Effects on Blow-By

2009 ◽  
Author(s):  
Richard Mittler ◽  
Albin Mierbach ◽  
Dan Richardson
Keyword(s):  
Piston Ring ◽  
Analytical Tool ◽  
Operating Conditions ◽  
Axial Motion ◽  
Oil Consumption ◽  
Piston Rings ◽  
Higher Power ◽  
Dynamic Loading Conditions ◽  
Physical Boundary ◽  
Engine Development

Advances in modern engine development are becoming more and more challenging. The intense increase of thermal and mechanical loads interacting in the combustion chamber as a result of higher power density requires perfecting the function of piston rings especially with regard to emission reduction technology. The major obstacle to predicting blow-by and oil consumption is the behavior of the piston rings under engine operating conditions. Design and functionality of a piston ring are highly influenced by the operating conditions. To understand the fundamentals of ring behavior and in this way the effects on blow-by and oil consumption, an analytical tool has been developed to transform the physical boundary conditions of engine kinematics and ring design into a reliable simulation. This paper describes the physical basics of ring movement under dynamic loading conditions and gives an overview of the results. It also was necessary to validate the model with real engine measurements to understand the fundamentals of ring design as a function of the described mathematics.

Effect of Top Piston Ring Wear on Its Sealing and Scraping Performance

2005 ◽  
Author(s):  
Andre Ferrarese ◽  
Amilton Sinatora ◽  
Fabio Luz Almeida
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Superior Performance ◽  
Test Results ◽  
Oil Consumption ◽  
Dimensional Parameter ◽  
Dimensional Parameters ◽  
Dimensional Variation ◽  
The Individual ◽  
Engine Components

New engines are presenting a constant increase of mechanical and thermal loads. The engine components should guarantee similar, or superior, performance than the baseline components in spite of the unfavorable wear conditions. For piston rings, the performance is given by the ring capacity of sealing and scraping. This performance can be measured in an engine by the lube oil consumption (LOC) and the gas flow to the crankcase (Blow-by) results. The purpose of this work is to evaluate the top piston ring wear influence on its sealing and scraping performance. Two engines were tested, one Otto and the other Diesel, in a dynamometer in order to quantify the top ring dimensional variation due to wear. Numerical simulations were performed in order to evaluate the individual influences of each dimensional parameter. The results of LOC and Blow-by were compared to literature data and engine test results of each engine. A proposal of combined effects among the dimensional parameters is presented.

Optimization of Piston Structure Aimed at Reducing Oil Consumption

2010 ◽  
Vol 146-147 ◽  
pp. 522-525
Author(s):  
Xu Dong Zhao ◽  
Shi Ying Liu ◽  
Shu Feng Song ◽  
Pei You Xiong
Keyword(s):  
Diesel Engine ◽  
Cylinder Liner ◽  
Engine Test ◽  
Oil Consumption ◽  
Ring Groove

Oil consumption of one certain diesel engine has been reduced by optimizing piston structure and piston kids clearance. The oil consumption principle inside the liner of engine was analyzed. Engine test was applied to validate the effect of the optimization. Due to the analysis, enlarge the pressure grads between piston top land and the 2nd land can push the 1st ring to the groove downside steadily. Adding or enlarging oil containing pocket above and below oil ring groove can reduce the oil pressure in these areas. Reasonable and large clearance between piston top land and cylinder liner help the gas burn completely.

Lubricant Flow Optimization of Large Two Stroke Marine Diesel Engine Piston Ring Packs

2016 ◽  
Author(s):  
Matthias Stark ◽  
Richard Mittler
Keyword(s):  
Piston Ring ◽  
Superior Performance ◽  
Exhaust Gas ◽  
Oil Consumption ◽  
Major Step ◽  
Oil Transportation ◽  
Lubrication Performance ◽  
Marine Diesel ◽  
Piston Ring Pack ◽  
Ring Pack

Approaching a characterization of different contributors to the lube oil balance of an engine becomes important when aiming at enhancing lubrication performance and reducing its contribution to exhaust gas emissions. It is essential to quantify relevant data helping to determine lubrication losses related to particular tribosystem components. Recent activities focused on rating distinct tribosystem component effects on their contribution to total lube oil consumption and the possibility to most effectively modify those. This paper thus describes the most effective tribosystem component modifications, consisting of the application of a substantially modified piston ring pack and the introduction of lube oil accumulating grooves in order to considerably enhance lubrication performance. A proper prediction of piston ring pack dynamics and tribodynamic effects on the lube oil film is essential to design a superior piston ring pack in terms of an optimized piston running behaviour and lube oil transportation. One major step designing such a ring pack is based on the consequent application of a novel 3D piston ring pack simulation tool to enhance lube oil transportation characteristics and distribution. Lube oil accumulating grooves are introduced to reduce lubrication losses due to so called ring pack spray. The ring pack spray is a result of accumulated lubricant in the pressurized piston ring pack expanding into the scavenge air receiver during the scavenging phase. Mentioned effect was analysed in detail in order to determine the amount of related lubricant losses. Investigations in this context lead to the application of lube oil accumulating grooves and hence can be considered an important design aspect to reduce total lube oil consumption. Tribosystem performance validation was performed on the basis of the application of an SO2 tracing technology on a full scale engine test in order to determine relevant tribosystem component modifications in real time. The sulphur content of fuel and lube oil considerably influences the formation of particulate matter in the exhaust gas, following chemical reactions of sulphur oxidation. Hence detecting SO2 in the exhaust gas is a direct measure to determine the amount of lubricant in the exhaust gas composition. Finally this report demonstrates measurement results describing the superior performance of the modified tribosystem.

Study on the effect of piston and piston ring specifications on oil consumption

2020 ◽  
Vol 2020 (0) ◽  
pp. J07119
Author(s):  
Bitong TAN ◽  
Tomoya TAKAKI ◽  
Yasuo MORIYOSHI ◽  
Tatuya KUBOYAMA
Keyword(s):  
Piston Ring ◽  
Oil Consumption

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.

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