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.

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.

Three Dimensional Ring Dynamics Modeling Approach for Analyzing Lubrication, Friction and Wear of Piston Ring-Pack

2017 ◽  
Author(s):  
K. G. Mahmoud ◽  
O. Knaus ◽  
T. Parikyan ◽  
M. Patete
Keyword(s):  
Friction And Wear ◽  
Piston Ring ◽  
Parameter Analysis ◽  
Engine Oil ◽  
Oil Consumption ◽  
Modeling Approach ◽  
Power Cylinder ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Cylinder Bore

The automotive industry is subjected to increasing pressure in order to improve fuel efficiency and reduce the CO2 emissions of internal combustion (IC) engines. The power cylinder system (piston, piston ring, and liner) contributes significantly to the friction losses, engine oil consumption and gas leakage called blow-by. The role of cylinder bore shape in engine performance has been the subject of several studies in recent years. High bore distortion must be avoided because it can lead to ring conformability issues, which leads to inadequate sealing resulting in increased blow-by and oil consumption. It also leads to asperity contact between the piston skirt and cylinder bore increasing friction causing abnormally high surface wear. Although bore distortion cannot be eliminated, engine manufacturers strive to contain it within acceptable limits. Therefore, numerical analysis of the power cylinder with physically based mathematical models becomes very essential to the engine and component manufacturer in order to reduce engine development lead time and minimize the number of engine tests. The integrated ring-pack modeling methodology developed by the authors [1] is used to investigate the piston ring-pack performance. Although the modeling approach can be used for extensive parameter analysis of piston, piston rings and lubrication oil consumption, the influence of the bore distortion on the ring conformability and its impact on blow-by, friction and wear is highlighted in this study. Piston tilting, piston ring twist and surface roughness of the piston ring and liner have been taken into consideration.

Computer Simulation of the Behavior of the Piston Ring Pack of Internal Combustion Engines

2016 ◽  
Vol 821 ◽  
pp. 166-171
Author(s):  
Peter Raffai ◽  
Pavel Novotný ◽  
Jozef Dlugoš
Keyword(s):  
Computer Simulation ◽  
Research And Development ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Internal Combustion ◽  
Optimization Process ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Piston Ring Pack ◽  
Ring Pack

The continuously tightening regulations limiting the amount of exhaust gas components of internal combustion engines force the manufacturers to further increase the effectivity of their power units. Due to the already relatively highly-developed state of engines result in the need of research and development of even smaller engine parts – e.g. piston rings. The main aim of this project was to develop a tool for the computer simulation of the behavior of the piston ring pack, which could aid the optimization process of the piston ring pack towards lowered friction losses.

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.

Predictive tool for frictional performance of piston ring-pack/liner conjunction

2019 ◽  
Vol 13 (3) ◽  
pp. 5513-5527
Author(s):  
J. W. Tee ◽  
S. H. Hamdan ◽  
W. W. F. Chong
Keyword(s):  
Film Thickness ◽  
Mathematical Models ◽  
Piston Ring ◽  
Published Data ◽  
Predictive Tool ◽  
Frictional Losses ◽  
Fundamental Understanding ◽  
Minimum Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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

scholarly journals An investigation into the oil transport and starvation of piston ring pack

2018 ◽  
Vol 233 (1) ◽  
pp. 112-124 ◽  
Author(s):  
SR Bewsher ◽  
M Mohammadpour ◽  
H Rahnejat ◽  
G Offner ◽  
O Knaus
Keyword(s):  
Film Thickness ◽  
Boundary Conditions ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Reverse Flow ◽  
Lubricant Film ◽  
Total Power ◽  
Lubricant Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

In order to accurately predict the lubricant film thickness and generated friction in any tribological contact, it is important to determine appropriate boundary conditions, taking into account the oil availability and extent of starvation. This paper presents a two-dimensional hydrodynamic model of a piston ring pack for prediction of lubricant film thickness, friction and total power loss. The model takes into account starvation caused by reverse flow at the conjunctional inlet wedge, and applied to a ring pack, comprising a compression and scraper ring. Inlet boundaries are calculated for an engine cycle of a four-cylinder, four-stroke gasoline engine operating at 1500 r/min with conditions pertaining to the New European Drive Cycle. The analysis shows the two main sources of starvation: first, due to a physical lack of inlet meniscus and second, due to reverse flow at the inlet wedge significantly affecting the prevailing conditions from the generally assumed idealised boundary conditions. Such an approach has not hitherto been reported in literature.

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.

Tribological effect of piston ring pack on the crankshaft torsional vibration of diesel engine

2014 ◽  
Vol 16 (7) ◽  
pp. 908-921
Author(s):  
Wanyou Li ◽  
Yibin Guo ◽  
Xiqun Lu ◽  
Xuan Ma ◽  
Tao He ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Torsional Vibration ◽  
Piston Ring ◽  
Piston Ring Pack ◽  
Ring Pack
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