Computer Program Development Predicting Engine Oil Consumption

Author(s):  
Sang Myung Chun

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.

2003 ◽  
Vol 125 (4) ◽  
pp. 1081-1089 ◽  
Author(s):  
Y. Piao ◽  
S. D. Gulwadi

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring-pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions, and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.


Author(s):  
Y. Piao ◽  
S. D. Gulwadi

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring–pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.


Author(s):  
K. G. Mahmoud ◽  
O. Knaus ◽  
T. Parikyan ◽  
M. Patete

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.


2018 ◽  
Author(s):  
Petr Veigend ◽  
Gabriela Necasov ◽  
Peter Raffai ◽  
Vclav Åtek ◽  
Jir Kunovsk

Author(s):  
Matthias Stark ◽  
Richard Mittler

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.


Author(s):  
F-M Meng ◽  
J-X Wang ◽  
K Xiao

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.


Author(s):  
Liang Liu ◽  
Tian Tian

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.


2009 ◽  
Vol 137 (2) ◽  
pp. 128-141
Author(s):  
Andrzej WOLFF

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


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