A Mixed Lubrication and Oil Transport Model for Piston Rings Using a Mass-Conserving Algorithm

1998 ◽  
Vol 120 (1) ◽  
pp. 199-208 ◽  
Author(s):  
S. D. Gulwadi
Keyword(s):  
Piston Ring ◽  
Transport Model ◽  
Numerical Study ◽  
Numerical Procedure ◽  
Lubricating Oil ◽  
Oil Consumption ◽  
Oil Accumulation ◽  
Oil Transport ◽  
Trailing Edges ◽  
Piston Ring Lubrication

A numerical study of the interactions between hydrodynamic/boundary lubrication, oil transport, and radial dynamics of a piston ring using a mass-conserving (cavitation) algorithm is presented. The scheme outlined in this investigation facilitates the calculation of the volume of oil accumulating at the leading and trailing edges of the piston ring as it scrapes against the line. The calculation of this oil accumulation is important in the estimation of lubricating oil consumption in engines. The numerical procedure employed in this study is capable of depicting the transition between the various modes of piston ring lubrication (hydrodynamic, mixed, and boundary) over an engine cycle, including the detachment of oil film from the ring and its subsequent re-attachment. Additionally, the effects of (a) liner lubricant availability and (b) ring face profiles on the oil accumulation are also discussed.

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 Effect of Cylinder Bore Distortion on Lube Oil Consumption and Blow-By

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Fatih Kagnici ◽  
Ozgen Akalin
Keyword(s):  
Finite Element ◽  
Piston Ring ◽  
Fourier Coefficients ◽  
Cylinder Block ◽  
Lubricating Oil ◽  
Oil Consumption ◽  
Engine Operation ◽  
Consumption Model ◽  
Cylinder Bore ◽  
Cylinder Bore Distortion

It is well known that cylinder bore deformations during engine operation cause a number of problems in piston ring lubrication. Particularly, the deterioration of piston ring and cylinder bore conformability results in a significant increase in lubricating oil consumption. Therefore, measurement and identification of cylinder bore distortion has been an important subject for engine designers. In this study, an analytical lubricating oil consumption model was developed for a diesel engine. Piston stiffness was identified as an important input parameter for the oil consumption model, and the stiffness matrix of the piston was calculated using finite element simulations. In addition, finite element analysis was performed to determine the distorted cylinder block shape in engine running conditions. Pressure curves and loads obtained in actual engine tests were used in the analysis. The Fourier coefficients of a distorted cylinder bore was calculated which characterize the deformed bore orders. Using these Fourier coefficients, several distorted bore shapes were regenerated, including a straight bore and the effect of each order on total lube oil consumption was investigated by means of the oil consumption model.

A Study on a Rotational Force Acting on the Piston Ring of a Gasoline Engine

2019 ◽  
Author(s):  
Kenta Tomizawa ◽  
Akemi Ito
Keyword(s):  
Piston Ring ◽  
Gasoline Engine ◽  
Periodic Wave ◽  
Operating Conditions ◽  
Wave Form ◽  
Oil Consumption ◽  
Rotational Force ◽  
Oil Transport ◽  
Ring Rotation ◽  
Cylinder Bore

Abstract Oil consumption of an engine causes particulate matter, poisoning catalysts and sometimes abnormal combustion like pre-ignition. One of the factors of oil consumption is oil transport via a piston ring-gap. Coincident of ring-gaps at a same position may cause an increase in oil consumption. In this research, the effect of coincident the ring gaps on oil consumption was measured using with/without the a stopper pin for the ring rotation by sulfur tracer method. A lot of spikes was found in the wave form of sulfur concentrate for the rings without the stopper pin, and higher value of oil consumption was simultaneously measured. Then the force which caused ring rotation (hereafter ‘rotational force’) was measured by a newly developed method. A cantilever was installed in the ring gap, and the strain gauges were pasted on the cantilever. Therefore, the rotational force was measured as the bending stress of the cantilever. It was found that the rotational force showed a periodic wave form against the crank angle. Furthermore, it was also found that the amplitude of the rotational force was strong affected by the engine operating conditions. The rotational force was also affected by the gap position. It was assumed that not only the piston lateral motion but also the cylinder bore shape affected the rotational force. The mechanism of generating the rotational force is the future subject.

Influence of the Position of Oil Drain Holes of a Piston on Lubricating Oil Consumption

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Hiroki Hasegawa ◽  
Koji Kikuhara ◽  
Akemi Ito ◽  
Shunsuke Nishijima ◽  
Masatsugu Inui ◽  
...  
Keyword(s):  
Piston Ring ◽  
Gasoline Engine ◽  
Pressure Sensors ◽  
Lubricating Oil ◽  
Oil Consumption ◽  
Tracer Method ◽  
Low Friction ◽  
Piston Skirt ◽  
Generation Mechanisms ◽  
Good Agreement

An increase in lubricating oil consumption in a gasoline engine causes an increase in particulate matters in exhaust gases, poisoning the catalyst after treatment devices, abnormal combustion in a turbo-charged gasoline engine, and so on. Recent trend of low friction of a piston and piston ring tends to increase in lubricating oil consumption. Therefore, reducing oil consumption is required strongly. In this study, the effect of the position of oil drain holes on oil pressure under the oil ring and lubricating oil consumption was investigated. The oil pressure under the oil ring is measured using fiber optic pressure sensors and pressure generation mechanisms were investigated. Lubricating oil consumption was also measured using sulfur tracer method and the effects of oil drain holes hence the oil pressure were evaluated. Four types of arrangement of oil drain holes were tested. The oil pressure variations under the oil ring in the circumferential direction was measured. An increase in oil pressure was found during down-stroke of the piston. The lowest oil pressure was found for the piston with four oil drain holes. Two holes nearby the front/rear end of the piston skirt showed relatively lower pressure. The measured results of oil consumption showed good agreement to measured oil pressure under the oil ring. It was found that oil pressure under the oil ring affected oil consumption, and oil drain holes set near the front/rear end of the piston skirt were effective for reducing oil consumption.

Piston-Ring Lubrication Problems for Refrigeration Compressors Considering Combined Effects of Supply Oil Quantity and Surface Roughness

1996 ◽  
Vol 118 (2) ◽  
pp. 286-291 ◽  
Author(s):  
H. Nakai ◽  
N. Ino ◽  
H. Hashimoto
Keyword(s):  
Surface Roughness ◽  
Friction Force ◽  
Piston Ring ◽  
Reynolds Equation ◽  
Numerical Procedure ◽  
Cylinder Wall ◽  
Combined Effects ◽  
One Dimensional ◽  
Modified Reynolds Equation ◽  
Piston Ring Lubrication

Reciprocating-type compressors are widely used for refrigeration systems, and an understanding of piston-ring lubrication in the compressor is vital for designers in reducing the energy losses due to friction because a substantial portion of friction in the compressors is attributable to the piston-ring assembly. This study aimed at developing a one-dimensional analysis for lubrication between the piston-ring and cylinder of refrigeration compressors considering the combined effects of supply oil quantity and surface roughness on piston-ring face and cylinder wall. In the theoretical model, the piston-ring is treated as a one-dimensional dynamically loaded bearing with combined sliding and squeezing motion. The one-dimensional modified Reynolds equation based on the average flow model by Patir and Cheng is used as a governing equation. In the analysis of the modified Reynolds equation, two-types of inlet boundary conditions, flooded condition and starvation condition, are applied at the leading edge according to the supply oil quantity, and the Reynolds boundary condition is applied at the trailing edge. A numerical procedure is then developed to estimate the cyclic variation of minimum film thickness, inlet and outlet positions of lubrication film and friction force, and the combined effects of supply oil quantity and surface roughness height are examined for a typical refrigeration compressor. It is clarified from the numerical results that the supply oil quantity and surface roughness affect significantly the friction force of the piston-ring for refrigeration compressors.

A mass-conserving algorithm for piston ring dynamical lubrication problems with cavitation

2018 ◽  
Vol 70 (1) ◽  
pp. 212-229 ◽  
Author(s):  
Zhenpeng He ◽  
Wenqin Gong ◽  
Weisong Xie ◽  
Guichang Zhang ◽  
Zhenyu Hong
Keyword(s):  
Density Distribution ◽  
Pressure Distribution ◽  
Piston Ring ◽  
Lubricating Oil ◽  
Asperity Contact ◽  
Two Dimensional ◽  
Cavitation Model ◽  
Film Rupture ◽  
Content Type ◽  
Piston Ring Lubrication

Purpose Piston ring dynamic problem plays an important role in the lubricant characteristics of a reciprocating engine, which lead to engine wear and the increased consumption of lubricating oil. A cavitation analysis of the piston ring lubrication with two-dimensional Reynolds equation has rarely been reported owing to the complex working condition. The purpose of this study is to establish a precise model that can provide guidance for the design of the piston ring. Design/methodology/approach In this paper, a cavitation model and its effect on the piston ring lubrication was studied in a simulation program based on the mass-conserving theory which is solved by means of the Newton–Raphson method. In this study, some models such as mixed lubrication, asperity contact, blow-by/blow-back flow and cavitation have been coupled with the lubrication model. Findings The established model has been compared with the traditional model that deals with cavitation by using the Reynolds boundary condition algorithm. The cavitation zone, pressure distribution and density distribution between the piston ring and the cylinder have also been predicted. Studies of the changing trend for the pressure distribution and the cavitation zone at few typical crank angles have been listed to illustrate the cavitation changing rule. The analysis of the results indicates that the developed simulation model can adequately illustrate the lubrication problem of the piston ring system. All the analyses will provide guidance for the oil film rupture and the reformation process. Originality/value A two-dimensional cavitation model based on the mass-conserving theory has been built. The cavitation-forming and -developing process for the piston ring–liner lubrication has been studied. Non-cavitation occurs in the vicinity of top dead center and bottom dead center. The non-cavitation period will be longer in the vicinity of 360° of crank angle. The density distribution in the cavitation zone can be obtained.

A Three-Dimensional Analysis of Piston Ring Lubrication Part 2: Sensitivity Analysis

1995 ◽  
Vol 209 (1) ◽  
pp. 15-27 ◽  
Author(s):  
M-T Ma ◽  
E H Smith ◽  
I Sherrington
Keyword(s):  
Sensitivity Analysis ◽  
Piston Ring ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Favourable Effect ◽  
Oil Consumption ◽  
Three Dimensional Model ◽  
Dimensional Theory ◽  
Factors Affecting ◽  
Piston Ring Lubrication

A three-dimensional model, developed by the authors, incorporating axial and circumferential variations in film shape and squeeze effects has been presented in Part 1 (1). In order to verify this model, the minimum film thicknesses predicted by the authors' model are compared with the predictions of an axisymmetric (two-dimensional) theory and with experimental results presented by Brown (2). A sensitivity analysis is then presented. A number of important factors affecting piston ring performance are examined. They include ring lateral location, constant ring twist (or offset of the ring face profile), bore out-of-roundness, liner temperature distribution and barrel height of the ring face profile. The results indicate that most of these factors have a considerable influence on piston ring performance. Notably, it is shown that ring lateral displacement and bore distortion can have a favourable effect on energy consumption provided blow-by and excessive oil consumption are avoided.

scholarly journals The effect of friction force and cavitation on wear in piston-cylinder assemblies

2018 ◽  
Vol 188 ◽  
pp. 04012
Author(s):  
Polychronis Dellis
Keyword(s):  
Transport Process ◽  
Piston Ring ◽  
Load Capacity ◽  
Engine Performance ◽  
Cylinder Liner ◽  
Ring Test ◽  
Sufficient Evidence ◽  
Oil Consumption ◽  
Two Phase ◽  
Piston Ring Lubrication

Both in engines and test rigs, cavitation in piston-ring lubrication is a subject studied by many researchers in the past. Although there is no sufficient evidence of cavitation erosion on the surface of the liner, this phenomenon is studied as part of the lubricant transport process. During the transport process the lubricant enters the combustion chamber. The combustion products of consumed oil might contribute to exhaust gas emissions and with emission legislation becoming more stringent, it is important that oil consumption is reduced to the lowest level possible. The role of the piston-rings is becoming more complex with the imposed requirements for lower oil consumption and friction. The piston-ring pack role on engine performance, durability and wear, is becoming on the other hand, more demanding. Between the piston-ring and cylinder liner, cavitation occurs as a result of two-phase liquid flow. Cavitation has long been recognized to degrade performances in most engineering applications and its effect in piston-ring lubrication is that it alters the oil film pressure profile, generated at the converging-diverging wedge of the piston-ring. An area of the piston-ring surface is void, corresponds to subatmospheric pressures and thus, the piston-ring load capacity is altered. Two experimental rigs were used, a simplified single-ring test rig that simulates the piston-ring liner movement at speeds corresponding to idle but the movement is reversed and a single cylinder diesel engine that was used for visualization results only, after the necessary modifications.

Sign in / Sign up

Export Citation Format

Share Document