Film Thickness and Friction Measurement of Piston Ring Cylinder Liner Contact With Corresponding Modeling Including Mixed Lubrication

2004 ◽  
Author(s):  
Nathan W. Bolander ◽  
Brian D. Steenwyk ◽  
Ashwin Kumar ◽  
Farshid Sadeghi
Keyword(s):  
Film Thickness ◽  
Analytical Model ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Mixed Lubrication ◽  
Lubricant Film ◽  
Asperity Contact ◽  
Lubricant Film Thickness ◽  
Lubrication Regimes ◽  
Experimental Apparatus

An experimental apparatus and an analytical model have been developed to investigate and determine the lubrication condition and frictional losses at the interface between a piston ring and cylinder liner. The experimental apparatus features twin fiber optic displacement sensors to accurately measure the lubricant film thickness and a tri-axial piezoelectric force transducer to simultaneously measure frictional force. An analytical mixed lubrication model featuring Elrod cavitation and a stochastic/deterministic approach for asperity contact was used to investigate the effects of boundary and mixed lubrication conditions at the ends-of-stroke. A comparison between experimental and analytical results indicated that they are in good agreement. The results illustrate the transition through all of the different lubrication regimes (i.e. boundary, mixed and hydrodynamic lubrication) the piston ring and liner experience during a stroke. The twin displacement sensor arrangement is capable of producing accurate, repeatable measurements of lubricant film thickness that are in agreement with the analytical predictions. The analytical model developed for this study can capture the different lubrication regimes that the piston ring and liner experience.

A Mixed-Lubrication Study of Journal Bearing Conformal Contacts

1997 ◽  
Vol 119 (3) ◽  
pp. 456-461 ◽  
Author(s):  
Qian (Jane) Wang ◽  
Fanghui Shi ◽  
Si C. Lee
Keyword(s):  
Film Thickness ◽  
Contact Pressure ◽  
Contact Area ◽  
Numerical Solutions ◽  
Mixed Lubrication ◽  
Lubricant Film ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Lubricant Film Thickness ◽  
Asperity Contacts

Numerical analyses of finite journal bearings operating with large eccentricity ratios were conducted to better understand the mixed lubrication phenomena in conformal contacts. The average Reynolds equation derived by Patir and Cheng was utilized in the lubrication analysis. The influence function, calculated numerically using the finite element method, was employed to compute the bearing deformation. The effects of bearing surface roughness were incorporated in the present analysis for the calculations of the asperity contact pressure and the asperity contact area. The numerical solutions of the hydrodynamic and asperity contact pressures, lubricant film thickness, and asperity contact area were evaluated based on a simulated bearing-journal geometry. The calculations revealed that the asperity contact pressure may vary significantly along both the width and the circumferential directions. It was also shown that the asperity contacts and the lubricant film thickness were strongly dependent on the bearing width, asperity orientation, and operating conditions.

The influence of surface texturing on the transition of the lubrication regimes between a piston ring and a cylinder liner

2016 ◽  
Vol 18 (8) ◽  
pp. 785-796 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Di Zhang
Keyword(s):  
Piston Ring ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Mixed Lubrication ◽  
Textured Surface ◽  
Asperity Contact ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Stribeck Curves

This article employs a mixed lubrication model to investigate the performance of the textured surface. The Jakobsson–Floberg–Olsson model is used to obtain the hydrodynamic support of the textured conjunction, while the calculation of the asperity contact load is based on the load-sharing concept. Based on the simulated Stribeck curves of the smooth surface and the textured surface, comparisons are conducted to study the effect of texturing under different lubrication regimes. It appears that the transition of lubrication regimes is influenced by the texturing parameters and the convergence degrees of conjunction. The presence of textures delays the appearance of the mixed lubrication regime and the boundary lubrication regime.

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.

Piston Ring-Cylinder Bore Friction Modeling in Mixed Lubrication Regime: Part I—Analytical Results

1999 ◽  
Vol 123 (1) ◽  
pp. 211-218 ◽  
Author(s):  
Ozgen Akalin ◽  
Golam M. Newaz
Keyword(s):  
Boundary Conditions ◽  
Friction Force ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Surface Flow ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Friction Modeling ◽  
Crank Angle ◽  
Cylinder Bore

An axi-symmetric, hydrodynamic, mixed lubrication model has been developed using the averaged Reynolds equation and asperity contact approach in order to simulate frictional performance of piston ring and cylinder liner contact. The friction force between piston ring and cylinder bore is predicted considering rupture location, surface flow factors, surface roughness and metal-to-metal contact loading. A fully flooded inlet boundary condition and Reynolds boundary conditions for cavitation outlet zone are assumed. Reynolds boundary conditions have been modified for non-cavitation zones. The pressure distribution along the ring thickness and the lubricant film thickness are determined for each crank angle degree. Predicted friction force is presented for the first compression ring of a typical diesel engine as a function of crank angle position.

Continuous Lubricant Film Thickness Measurement Between Piston Ring and Cylinder Bore

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Yunus Emre Ayranci ◽  
Ozgen Akalin
Keyword(s):  
Film Thickness ◽  
Piston Ring ◽  
Fiber Optic ◽  
Thickness Measurement ◽  
Test System ◽  
Lubricant Film ◽  
Laser Source ◽  
Bench Test ◽  
Lubricant Film Thickness ◽  
Cylinder Bore

Measurement of film thickness between piston ring and cylinder bore has been a challenge for decades; laser-induced fluorescence (LIF) method was used by several groups, and promising results are obtained for the investigation of lubricant film transport. In this study, blue light generated by a laser source is transmitted to a beam splitter by means of a fiber optic cable and combined with another fiber optic line, then transmitted to the piston ring and cylinder bore conjunction. The light causes the fluorescence dye present in the lubricant to emit light in a longer wavelength, i.e., green. Reflected light is recollected; blue wavelength components are filtered out using a narrow band pass optical filter, and only components in the florescence wavelength is transmitted to a photomultiplier tube. The photomultiplier produces a voltage proportional to instantaneous lubricant film thickness. Then, the photomultiplier signal is calibrated for lubricant film thickness using a laser textured cylinder bore with known geometries. Additional marks were etched on the liner for calibration. The LIF system is adapted to a piston ring and cylinder bore friction test system simulating engine conditions. Static piston ring and reciprocating liner configuration of the bench test system allow the collection of continuous lubricant film thickness data as a function of crank angle position. The developed system has potential to evaluate new designs, materials, and surface properties in a controlled and repeatable environment.

Continuous Lubricant Film Thickness Measurement Between Piston Ring and Cylinder Bore

2017 ◽  
Author(s):  
Yunus Emre Ayranci ◽  
Ozgen Akalin
Keyword(s):  
Film Thickness ◽  
Piston Ring ◽  
Fiber Optic ◽  
Thickness Measurement ◽  
Test System ◽  
Lubricant Film ◽  
Laser Source ◽  
Bench Test ◽  
Lubricant Film Thickness ◽  
Cylinder Bore

Measurement of film thickness between piston ring and cylinder bore has been a challenge for decades; laser induced fluorescence method (LIF) was used by several groups and promising results are obtained for the investigation of lubricant film transport. In this study, blue light generated by a laser source is transmitted to a beam splitter by means of a fiber optic cable and combined with another fiber optic line, then transmitted to the piston ring and cylinder bore conjunction. The light causes the fluorescence dye present in the lubricant to emit light in a longer wavelength, i.e. green. Reflected light is recollected; blue wavelength components are filtered out using a narrow band pass optical filter, and only components in the florescence wavelength is transmitted to a photomultiplier tube. The photomultiplier produces a voltage proportional instantaneous lubricant film thickness. Then, the photomultiplier signal is calibrated for lubricant film thickness using a laser textured cylinder bore with known geometries. Additional marks were etched on the liner for calibration. The LIF system is adapted to a piston ring and cylinder bore friction test system simulating engine conditions. Static piston ring and reciprocating liner configuration of the bench test system allows the collection of continuous lubricant film thickness data as a function of crank angle position. The developed system has potential to evaluate new designs, materials and surface properties in a controlled and repeatable environment.

Elastohydrodynamic Film Thickness in Concentrated Contacts: Part 1: Experimental Investigation for Lubricant Entrainment Aligned with the Major Axis of the Contact Ellipse

1986 ◽  
Vol 200 (3) ◽  
pp. 207-217 ◽  
Author(s):  
R J Chittenden ◽  
D Dowson ◽  
C M Taylor
Keyword(s):  
Experimental Investigation ◽  
Film Thickness ◽  
Major Axis ◽  
Lubricant Film ◽  
Capacitance Measurement ◽  
Experimental Investigations ◽  
Lubricant Film Thickness ◽  
Wide Range ◽  
Experimental Apparatus ◽  
Contact Ellipse

Experimental investigations of the lubricant film thickness generated in elastohydrodynamic elliptical contacts have been undertaken since the early 1960s. The majority of these studies has been concerned with circular or near circular contact situations, although a wide range of geometries in which lubricant entrainment was directed along the minor axis of the contact ellipse has also been considered. The information available on lubricant film thickness in geometrical conditions where lubricant entrainment was aligned with the major axis of the contact ellipse has, however, been severely limited. The experimental investigation described in this paper is therefore concerned with the measurement of lubricant film thickness in the unusual geometrical conditions recently analysed theoretically by the authors (1, 2). The measurements were made with the aid of a twin disc machine for geometries ranging from a radius ratio of unity down to a value of 0.112. The experimental apparatus is described and details are given of the special test discs which were manufactured to produce such geometries. The capacitance measurement technique adopted is detailed along with the numerical model developed to allow the measured values of inter-disc capacitance to be interpreted in terms of the lubricant film thickness. The lubricant film thickness developed in four geometrical situations was investigated at four rotational speeds and five loads. This allowed a comparison to be made with the film thickness values predicted by recent elastohydrodynamic theory for changes in both speed and load. The film thickness deduced from the capacitance measurements was considered to be representative of that found at the centre of contact, and good agreement was found between experiment and all aspects of the theoretical predictions.

The Film Thickness in Piezoviscous-Rigid Regime; Film Thickness Lubrication Regimes Transition Criteria

1984 ◽  
Vol 106 (3) ◽  
pp. 375-381 ◽  
Author(s):  
L. Houpert
Keyword(s):  
Film Thickness ◽  
General Formula ◽  
Lubricant Film ◽  
Lubricant Film Thickness ◽  
Dimensionless Parameters ◽  
Lubrication Regimes ◽  
Lubrication Film ◽  
Lubrication Regime ◽  
Transition Criteria

A new general formula is proposed to calculate the lubricant film thickness in the piezoviscous rigid lubrication regime. Equivalent radii ratio, load, speed, and material dimensionless parameters are included. New general criteria to decide whether piezoviscous rigid or EHD (elasto-hydrodynamic) or isoviscous elastic lubrication film thickness formulas have to be used are proposed. Comparisons with some other published results are made.

Numerical Simulation of Piston Ring in Mixed Lubrication—A Nonaxisymmetrical Analysis

1994 ◽  
Vol 116 (3) ◽  
pp. 470-478 ◽  
Author(s):  
Yuanzhong Hu ◽  
Herbert S. Cheng ◽  
Takayuki Arai ◽  
Yoichi Kobayashi ◽  
Shunichi Aoyama
Keyword(s):  
Film Thickness ◽  
Load Distribution ◽  
Piston Ring ◽  
Mixed Lubrication ◽  
Contact Load ◽  
Asperity Contact ◽  
Static Distortion ◽  
Piston Ring Lubrication ◽  
Cylinder Bore

The assumption of axisymmetry, employed by most of studies on piston ring lubrication, probably gives a too idealistic model for the real situation. A theoretical model for a nonaxisymmetrical analysis of piston ring lubrication has been established in the present study. When a piston ring with an arbitrary free shape is fitted into the cylinder bore, the determination of ring deflection and contact load has been modeled mathematically as a Linear Complementary Problem (LCP). By combining LCP solution with lubrication analysis, the film thickness and contact load distribution over the circumference are obtained, leading to a more realistic simulation for piston ring lubrication. The friction force between piston ring and cylinder bore is predicted by the mixed lubrication model including the effects of surface roughness and asperity contact. The static distortion of cylinder bore, gas pressure variation, and lubricant starvation are also considered in the simulation. Results show that the contact pattern and film thickness between piston ring and cylinder bore are not exactly axisymmetrical. The main reason for the nonuniform contact is the asymmetry of ring elasticity, the static distortion and dynamic load created by the secondary movement of piston skirt.

Sign in / Sign up

Export Citation Format

Share Document