Piston Ring-Cylinder Bore Friction Modeling in Mixed Lubrication Regime: Part II—Correlation With Bench Test Data

1999 ◽  
Vol 123 (1) ◽  
pp. 219-223 ◽  
Author(s):  
Ozgen Akalin ◽  
Golam M. Newaz
Keyword(s):  
Friction Coefficient ◽  
Test Data ◽  
Piston Ring ◽  
Normal Load ◽  
Test System ◽  
Mixed Lubrication ◽  
Contact Temperature ◽  
Bench Test ◽  
Crank Angle ◽  
Contact Width

A bench friction test system for piston ring and liner contact, which has high stroke length and large contact width has been used to verify the analytical mixed lubrication model presented in a companion paper (Part 1). This test system controls the speed, temperature and lubricant amount and records the friction force, loading force, crank angle signal and contact temperature data simultaneously. The effects of running speed, applied normal load, contact temperature and surface roughness on friction coefficient have been investigated for conventional cast-iron cylinder bores. Friction coefficient predictions are presented as a function of crank angle position and results are compared with bench test data. Analytical results correlated well with bench test results.

Frictional Characteristics of IF-WS2 Nanoparticles in Simulated Engine Conditions

2009 ◽  
Author(s):  
Burak Gullac ◽  
Ozgen Akalin
Keyword(s):  
Piston Ring ◽  
Normal Load ◽  
Mineral Oil ◽  
Test System ◽  
Mixed Lubrication ◽  
Bench Test ◽  
Inorganic Fullerene ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Cylinder Bore

The effect of inorganic fullerene-like (IF) WS2 nanoparticles added to mineral oil which has a potential to reduce engine friction was investigated using a reciprocating piston ring - cylinder bore bench test system. The test system simulates actual engine conditions controlling oil temperature, speed, and normal load. Frictional characteristics of various IF-WS2 nanoparticle concentrations in mineral oil were experimentally analyzed. After a certain period of running in mixed lubrication regime, a significant reduction in friction coefficient was observed when the IF-WS2 formulated oil was used. This reduction remains to some extent with the reference mineral oil even after solvent cleaning. The results show that a thin tribofilm gradually forms on the piston ring and the cylinder bore surfaces that reduce the coefficient of friction in mixed lubrication regime. The effects of lubrication regime, load, speed, temperature and surface roughness on tribofilm formation were also discussed.

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.

A Global Tribological Approach of Friction Dry Contact Polymer with SGF on Steel, in Terms of Consequences on Metallic Surface Condition (Comparative Wear Coefficients of Steel Surface)

2015 ◽  
Vol 723 ◽  
pp. 927-942 ◽  
Author(s):  
Virgil Florescu ◽  
Lucian Capitanu ◽  
Dorin Rus
Keyword(s):  
Friction Coefficient ◽  
Steel Surface ◽  
Plastic Material ◽  
Normal Load ◽  
Contact Temperature ◽  
Metallic Surface ◽  
Linear Wear ◽  
Sliding Speed ◽  
Dry Contact ◽  
Steel Surfaces

In this paper, we present a global tribological approach of friction dry contact polymer with SGF on steel, in terms of consequences on metallic surface condition (comparative wear coefficients of polished steel surface) based on extensive experimental determinations between the value and the evolution of the friction coefficient, wear of steel surfaces and contact temperature, in the case of linear dry contact, for thermoplastic material reinforced with short glass fibers (SGF) and various steel surfaces. The aim was to highlight the evolution of the wear process depending on the friction coefficient, as well as the dependence of the loading wear and the sliding speed. Wear depth and volume were calculated based on the “wear imprint” method. As a result, it was possible to graphically illustrate the evolution of the friction coefficient, of the contact temperature, and the change of the wear process, emphasizing the abrasive, adhesive and corrosive wear. The evolution of the plastic material transfer function of the contact temperature, namely of the power lost by friction was highlighted. It has been demonstrated that in the case of a 30% SGF content it can reach and even exceed contact temperatures very close to the yield limit of the plastic material. The influence of the normal load and sliding speed was evaluated in detail. The influence of SGF content, normal load, relative sliding speed and contact temperature over the metal surface wear and over the nature of wear mechanism was recorded. The reaction to wear of different steel surfaces in linear dry friction contact on polymers with SGF (polyamide + 20% SGF, polyamide + 30% SGF and polycarbonate with 20% SGF), observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.). Thus, authors' findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component are presented, which generally is specific to the polymers’ friction. Authors’ detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4mm/h, respectively the order of volumetric wear rate is of 10-6cm3/h. The resulting comparative volumetric wear coefficients are of the order (10-11to 10-12) cm3/cm and respectively linear wear coefficients of 10-9mm/cm.

Boundary Lubrication Model under Square Surface Contact Condition

2010 ◽  
Vol 29-32 ◽  
pp. 1396-1401
Author(s):  
Wei Zu Wang ◽  
Liu Yi Wang ◽  
Zeng Xue Zhang ◽  
Hai Bo Chen
Keyword(s):  
Friction Coefficient ◽  
Boundary Lubrication ◽  
Contact Area ◽  
Normal Load ◽  
Contact Temperature ◽  
Sliding Speed ◽  
Surface Contact ◽  
Relative Deficiency ◽  
Frictional Surfaces ◽  
Relationship Of

The contact temperature of the frictional surfaces under boundary lubrication in square surface contact is calculated according to classic heat conduction theories. The friction coefficient of boundary lubrication is expressed with the friction coefficient of boundary film and direct contact. Then, a model is developed based on the relationship of adsorption heat, friction coefficient and contact temperature. The model is used to solve a sample question. The results illuminate that when the applied load is relatively small, the friction coefficient keeps at a stable small value with the variation of the sliding speed and the load. However, when the load reaches a certain value, the increase of the sliding speed or the normal load both leads to the increase of the friction coefficient. The friction coefficient is also increases with the increase of the contact temperature. The relative deficiency of oil, which indicates the proportion of the true contact area to mean contact area, has almost the same variation trend of the friction coefficient.

Design of Road Test and Evaluation System for Vehicle Handling and Stability

2014 ◽  
Vol 505-506 ◽  
pp. 281-285
Author(s):  
Ming Qiu Gao ◽  
Run Qing Guo ◽  
Rong Liang Liang
Keyword(s):  
Data Processing ◽  
Test Data ◽  
Evaluation System ◽  
Test System ◽  
Stability Test ◽  
Road Test ◽  
Vehicle Handling ◽  
Test And Evaluation ◽  
Test Result

Vehicle handling and stability has effect on positive safety of automotive directly. Test system of handling and stability is built for its road test and the test variables signal can be acquired and stored synchronously. Based on MATLAB GUI, software is developed for the test data processing, so that the stored data is to be analyzed and handling and stability test result is given by the software automatically. Using the test system in paper, handling and stability road test of one domestic sedan is fulfilled and scored, which verifies the applicability of the test system and scoring software in paper.

Friction Characteristics with Pin-on-Disc Friction Test on Microstructured Surface Using Whirling Electrical Discharge Texturing

2014 ◽  
Vol 1017 ◽  
pp. 417-422
Author(s):  
Vitchuda Lertphokanont ◽  
Takayuki Sato ◽  
Masahiro Oi ◽  
Minoru Ota ◽  
Keishi Yamaguchi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Electrical Discharge ◽  
Area Ratio ◽  
Mixed Lubrication ◽  
Optimal Conditions ◽  
Friction Test ◽  
Crater Diameter ◽  
Microstructured Surface ◽  
Pin On Disc ◽  
Lubrication Condition

A microstructured surface was created on a steel surface by whirling electrical discharge texturing (WEDT) since it was considered that the microstructures could act as lubricant reservoirs to assist the formation of a lubricating film, resulting in reduced friction. In this study, friction tests under engine oil were carried out over a range of loads and sliding speeds. In addition, the surface characteristics of the microstructured surface were also investigated to optimize the friction characteristics of the textured surface through pin-on-disc friction tests. It was found that under the mixed lubrication condition near the boundary condition, textured surfaces with texture-area ratio of approximately 6% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient. However, a texture-area ratio of approximately 4% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient under the mixed lubrication condition near the elastohydrodynamic lubrication condition. It was considered that when the normal load decreased, the lubrication region changed from the mixed lubrication condition to the hydrodynamic lubrication condition, which meant that the actual contact surface area decreased. The decrease in the actual contact surface area with decreasing texture-area ratio led to a reduction in the friction coefficient. Finally, it was clarified that the friction coefficient was reduced under the optimized conditions of the microstructured surface through a pin-on-disc friction test.

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