Investigation of the wear of engine journal bearings approaching severe lubrication conditions using a microabrasion tester

2019 ◽  
Vol 233 (12) ◽  
pp. 1939-1949 ◽  
Author(s):  
Andys Hernández-Peña ◽  
Leonardo I Farfan-Cabrera ◽  
Ezequiel A Gallardo-Hernández
Keyword(s):  
Boundary Lubrication ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Mineral Oil ◽  
Constant Load ◽  
Journal Bearings ◽  
Engine Operation ◽  
Lubrication Regimes ◽  
Actual Use ◽  
Steel Balls

Ideally, engine journal bearings are expected to operate under hydrodynamic lubrication regime to limit wear and promote minimal friction by sliding. Nevertheless, engine journal bearings fail since wear caused by severe conditions in actual engine operation, such as start/stop, misalignment, lubricant degradation, overheating, and debris contamination, producing a transition from hydrodynamic to mixed and boundary lubrication regimes and wear increased in both engine journal bearings and crankshaft. Thus, this work aims to study the influence of boundary lubrication, engine mineral oil aging, and debris contamination on wear of engine journal bearings. An adapted microscale abrasion tester using a ball-on-concave flat configuration was used to reproduce boundary lubrication under controlled conditions. Steel balls having a similar surface than crankshafts and concave flat samples cut from actual engine journal bearings were tested. The tests were run under boundary lubrication at a constant load, speed, and sliding distance at 26 ℃ and 100 ℃ using separately clean fresh and aged engine mineral oil, and then, tests were conducted using the oils contaminated with hard abrasive particles. The engine mineral oil was degraded by a laboratory aging process approaching oxidation of an engine mineral oil used in actual use conditions. Oxidation, additives depletion and changes in viscosity were evaluated. The wear volumes and scar morphologies of engine journal bearing samples were analyzed. The results suggested that high temperature was the main contributor for wear increase in engine journal bearings, while oil aging and debris did not influence considerably on the wear. However, the oils contaminated with hard particles produced a wear decrease in engine journal bearing samples but increased wear in rotary balls.

Performance of Stern Tube Bearings under Different Lubrication and Operating Conditions

2009 ◽  
Author(s):  
Jan H. Andersen ◽  
Hiroyuki Sada ◽  
Seiji Yamajo
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Water Soluble ◽  
Analysis Tool ◽  
Test Rig ◽  
Experimental Performance ◽  
Shaft Alignment ◽  
Alignment Analysis

This paper presents the results of an investigation into the theoretical and experimental performance of oil lubricated journal bearings. DNV has developed a new calculation tool for the analysis of journal bearing performance as part of shaft alignment analysis. The results of the calculation tool have been compared to other research and analysis methods under static and dynamic conditions. In addition, white metal bearings were tested with decreasing Sommerfeld number until loss of hydrodynamic lubrication. The experiments were carried out in a bearing test rig and with three different lubricants, normal mineral oil, emulsifying oil, and water-soluble oil. The tests were done with increasing water content in the lubricant. Results from the test were compared with calculation using the DNV analysis tool.

scholarly journals A Method for Monitoring Lubrication Conditions of Journal Bearings in a Diesel Engine Based on Contact Potential

2020 ◽  
Vol 10 (15) ◽  
pp. 5199
Author(s):  
Biao Wan ◽  
Jianguo Yang ◽  
Sicong Sun
Keyword(s):  
Diesel Engine ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Asperity Contact ◽  
Contact Potential ◽  
Axis Orbit ◽  
Lubrication Condition ◽  
The Relationship ◽  
Lubrication Conditions

Wear of the journal bearings in a diesel engine is usually caused by asperity contact. Increased contact potential is caused by the asperity contact between the journal bearing and the shell. This paper analyzes the relationship between the contact potential and asperity contact and presents a method based on contact potential to monitor the bearing wear caused by asperity contact. A thermo-elastic hydrodynamic lubrication (THL) model of the journal bearing on the test bench was established and was verified by measuring its axis orbit. The asperity contact proportion was calculated based on this THL model, and its relationship with the measured contact potential was determined. The main contribution of this paper is to present a new method for monitoring the lubrication conditions of journal bearings in a diesel engine based on contact potential. The results showed that (a) when the minimum oil film thickness was less than 5 μm, asperity contact occurred between the bearing shell and the journal, which led to a sharp increase in contact pressure and a rapid increase in friction power consumption. Further, (b) there was a positive correlation between contact potential and asperity contact. The contact potential was greater than 0.75 mv when asperity contact occurred. These results proved that asperity contact could be accurately monitored using the contact potential, and the feasibility of using the contact potential to monitor the lubrication condition of a bearing was verified.

A Numerical Solution for the Hydrodynamic Lubrication of Finite Porous Journal Bearings

1973 ◽  
Vol 187 (1) ◽  
pp. 71-78 ◽  
Author(s):  
B. R. Reason ◽  
D. Dyer
Keyword(s):  
Numerical Solution ◽  
Numerical Method ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Approximate Solutions ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Variable Porosity ◽  
Present Solution

We present a numerical solution for the operating conditions of a hydrodynamic porous journal bearing. The numerical method allows for the possibility of variable porosity in the bearing matrix, but the solution has been achieved on the assumption of matrix homogeneity. The relation between the various bearing parameters have been shown for a variety of bearing geometries and permeabilities enabling the operating conditions for this type of bearing to be better appreciated. A comparison of the present solution with approximate solutions used by other authors has been made, which indicates the useful working range of the approximate solutions.

The Hydrodynamic Lubrication of Rough Journal Bearings

1973 ◽  
Vol 95 (2) ◽  
pp. 166-172 ◽  
Author(s):  
H. Christensen ◽  
K. Tonder
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Hydrodynamic Theory ◽  
Finite Width ◽  
Hydrodynamic Theory Of Lubrication

In a number of previous papers a hydrodynamic theory of lubrication of rough bearing surfaces has been developed. The present paper describes the application of this theory to the analysis of the full journal bearing of finite width. The analysis demonstrates how the roughness influences the characteristics of the bearing and also shows how roughness interacts with features of nominal geometry and operating factors to determine the bearing response.

A Contribution to the Analysis of the Thermo-Hydrodynamic Lubrication of Porous Self-Lubricating Journal Bearings

2010 ◽  
Vol 297-301 ◽  
pp. 618-623 ◽  
Author(s):  
S. Boubendir ◽  
Salah Larbi ◽  
Rachid Bennacer
Keyword(s):  
Thermal Effects ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Porous Matrix ◽  
Journal Bearings ◽  
Governing Equations ◽  
Hydrodynamic Analysis ◽  
Result Show

In this work the influence of thermal effects on the performance of a finite porous journal bearing has been investigated using a thermo-hydrodynamic analysis. The Reynolds equation of thin viscous films is modified taking into account the oil leakage into the porous matrix, by applying Darcy’s law to determine the fluid flow in the porous media. The governing equations were solved numerically using the finite difference approach. Obtained result show a reduction in the performance of journal bearings when the thermal effects are accounted for and, this reduction is greater when the load capacity is significant.

The Effect of Oil Supply Pressure on the Circumferential Pressure Profile in Hydrodynamic Journal Bearing

2013 ◽  
Vol 315 ◽  
pp. 809-814 ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
Rob Dwyer-Joyce ◽  
Nik Rosli Abdullah
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Pressure Profile ◽  
Journal Bearings ◽  
Maximum Pressure ◽  
Oil Supply ◽  
Supply Pressure ◽  
Machine Elements ◽  
Hydrodynamic Journal Bearing ◽  
Circumferential Pressure

In hydrodynamic lubrication, the pressure condition of the fluid is critical to ensure good performance of the lubricated machine elements such as journal bearings. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on pressure profile around the circumference of a journal bearing. A journal diameter of 100mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 Mpa) and the circumferential pressure results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the maximum pressure values were affected by changes in oil supply pressure.

TRIBOLOGICAL CHARACTERISTICS OF RADIAL JOURNAL BEARINGS BY ULTRASONIC NANOCRYSTAL SURFACE MODIFICATION TECHNOLOGY

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3011-3016 ◽  
Author(s):  
YOUNG SHIK PYOUN ◽  
JEONG HYUN PARK ◽  
CHANG MIN SUH ◽  
INHO CHO ◽  
CHANG-SOON LEE ◽  
...  
Keyword(s):  
Surface Modification ◽  
Boundary Lubrication ◽  
Transition Period ◽  
Hydrodynamic Lubrication ◽  
Peak Torque ◽  
Bearing Steel ◽  
Journal Bearings ◽  
Mixed Lubrication ◽  
Stribeck Curve ◽  
Lubrication Condition

Ultrasonic nanocrystal surface modification (UNSM) has applied to a radial journal bearings made of bearing steel SUJ2. Mechanical characteristics are compared between UNSM treated and untreated bearings. Friction torque is measured at the boundary lubrication condition, the mixed lubrication condition, and the full hydrodynamic lubrication condition. The peak torque at the boundary lubrication condition and the transition period to mixed lubrication condition on the UNSM treated samples are reduced. These effects are very useful to improve the service life of journal bearings. The Stribeck curve at the mixed and full hydrodynamic lubrication is derived and compared. The friction coefficient at these two regimes is reduced by more than 50%, which will do effective role for improvement of energy efficiency. The major effects for this reduction at three lubrication regimes could be explained in the terms of micro dimple surface.

Researches on Friction Performance of Water-Lubricated Polymer Composite Journal Bearings Based on Experiments

2014 ◽  
Vol 711 ◽  
pp. 57-60
Author(s):  
Geng Yuan Gao ◽  
Zhong Wei Yin ◽  
Dan Jiang ◽  
Xiu Li Zhang
Keyword(s):  
Carbon Fiber ◽  
Polymer Composite ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Test Rig ◽  
Friction Performance ◽  
Steel Sleeve ◽  
Almost All ◽  
The Given

A composite which is PTFE as a matrix with PEEK and carbon fiber as fillers is developed to fabricate the bush of water-lubricated journal bearings. The bush is fabricated with a new structure that a relatively large straight groove is opened in its upper part. A water-lubricated journal bearing made up of the bush and a steel sleeve is studied using purposed-built test rig. It is shown that the test bearing operates under hydrodynamic lubrication for almost all of the given conditions. The composite developed in the work is a promising material for water-lubricated journal bearings, and the new structure can be well used in water-lubricated journal bearings.

Modeling the Viscoelastic Effects in the Hydrodynamic Lubrication of Journal Bearing in a High-Torque Low Speed Diesel Engine

2017 ◽  
Author(s):  
Talha Zia ◽  
Syed Adnan Qasim ◽  
Raja Amer Azim
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Adhesive Wear ◽  
Hydrodynamic Lubrication ◽  
Physical Contact ◽  
Engine Operation ◽  
Low Speed ◽  
Viscoelastic Characteristics ◽  
High Torque ◽  
Simulation Results

Multi-grade diesel lubricants exhibit viscoelastic characteristics, which affect journal bearing lubrication of a high torque engine at a low speed. During engine operation the main end of the crankshaft journal is most vulnerable to the cyclic combustion loads and must be protected against adhesive wear. This research models the Newtonian behavior of a lubricant by solving the 2-D Reynolds equation and determining the film thickness between the bearing and the crankshaft. It is followed by solving the continuity and Navier-Stokes equations to ensure conservation of mass and momentum of the lubricant flows. The constitutive equations exhibiting viscoelastic characteristics are coupled with the momentum conservation equations to generate simulation results for non-Newtonian lubricant response. The steady state wedging and transient squeeze effects are studied for a viscoelastic engine lubricant at low speed. The simulation results for Newtonian and viscoelastic engine lubricants are analyzed separately and then compared for definite conclusions. The results show that at a low initial speed the Newtonian lubricant is not affective against the cyclic loads to prevent physical contact and wear of interacting surfaces. The viscoelastic characteristics of the lubricant visibly contribute towards improving the pressure and film thickness profiles of a high-torque low-speed engine. It reduces the chances of breakdown of lubricant film and enhances the life of crankshaft by preventing adhesive wear.

Numerical Investigation of the Flow in Hydrostatic Journal Bearings With Porous Material

2018 ◽  
Author(s):  
M. Böhle
Keyword(s):  
Porous Material ◽  
Numerical Method ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Volume Flow Rate ◽  
Load Capacity ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Volume Flow ◽  
Present Contribution

The numerical prediction of load capacity, stiffness, power loss etc. of hydrostatic journal bearings must be performed for technical applications. CFD offers one possibility but is time consuming. In the present contribution a fast working numerical method is introduced based on the numerical solution of the Reynolds equation for hydrodynamic lubrication (REHL). It is applied in order to examine the flow inside three-dimensional journal bearings. The emphasis lies on the treatment of journal bearings with porous material. By the application of porous material the lubricant can be fed uniformly around the shaft and therefore improves the reliability of the journal bearing. The contribution gives a short outline of the possibilities and limitations of the application of the REHL. A detailed description of a finite difference method is given by which the REHL is solved. It is described in detail how the load capacity, stiffness, volume flow rate etc. of classical hydrodynamic journal bearings and journal bearings with porous material can be treated by the REHL whereby the emphasis lies on the treatment of journal bearings with porous material. Darcy’s law is implemented in the numerical method in order to take into account the pressure loss of the porous material which is the flow restrictor of the journal bearing. Many results are shown and discussed. Pressure distributions, load capacity, volume flow rates through the porous material, direction of force for a hydrodynamic and porous bearing etc. are shown and discussed in dependence of the eccentricity of the shaft.

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