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.

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.

Effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions

2020 ◽  
Vol 21 (3) ◽  
pp. 301
Author(s):  
Chongpei Liu ◽  
Wanyou Li ◽  
Xiqun Lu ◽  
Bin Zhao
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Lubricating Oil ◽  
Asperity Contact ◽  
Adiabatic Flow ◽  
Lubrication Performance ◽  
Load Carrying ◽  
Edge Wear ◽  
Journal Misalignment

The textures on the bushing surface have important effects on the performance of journal bearing. In this study, the effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions are investigated theoretically. The journal misalignment, asperity contact and thermal effects are considered, while the profile modifications due to running-in are neglected. The Winkler/Column model is used to calculate the elastic deformation of bushing surface and the adiabatic flow hypothesis is adopted to obtain the effective temperature of lubricating oil. The numerical solution is established by using finite difference and overrelaxation iterative methods, and the rupture zone of oil film is determined by Reynolds boundary conditions. The numerical results reveal that the double parabolic profiles with groove textures with proper location and geometric sizes can increase load carrying capacity and reduce friction loss under steady operating conditions, which effectively overcome the drawbacks of double parabolic profiles. This novel bushing profile may help to reduce the bushing edge wear and enhance the lubrication performance of journal bearing.

Experimental and Analytical Research on Floating-Ring Bearings for Engine Applications

1990 ◽  
Vol 112 (1) ◽  
pp. 119-122 ◽  
Author(s):  
X. Dong ◽  
Z. Zhao
Keyword(s):  
Diesel Engine ◽  
Journal Bearing ◽  
Friction Pair ◽  
Journal Bearings ◽  
Nonstationary Load ◽  
Analytical Research ◽  
The Difference ◽  
Starting Speed ◽  
Frictional Coefficients

This study deals with whether floating-ring journal bearings can be applied to engine bearings or not. The performance of floating-ring journal bearings with nonstationary load is analyzed. The main bearings of a S195 4-stroke diesel engine are replaced by floating-ring bearings and an experiment is carried out with success. After the engine starting, the ring lifts off when crankshaft speeds approach seven hundred and forty rpm. The ring maintains its rotation until crankshaft speeds decrease to two hundred rpm, during its deceleration to a stop. Once the ring lifts off it remains in normal working order. It is possible for floating-ring bearings to be used in engines where the load is nonstationary. It is hoped that a further reduction in the ring starting speed will be provided by lessening the difference between dynamic and static frictional coefficients in friction pair and an increase in lifetime will be provided by the floating-ring journal bearing.

Modeling Shear Heating in the Hydrodynamic Lubrication of Crankshaft Journal Bearing of a High-Torque Diesel Engine Operating at a Low Speed

2017 ◽  
Author(s):  
Saqib Naseer ◽  
Syed Adnan Qasim ◽  
Raja Amer Azim
Keyword(s):  
Diesel Engine ◽  
Engine Speed ◽  
Journal Bearing ◽  
Adhesive Wear ◽  
Hydrodynamic Lubrication ◽  
Physical Contact ◽  
Low Speed ◽  
Viscous Shear ◽  
Shear Heating ◽  
High Torque

Journal bearing plays a critical role in carrying the extensive transient hydrodynamic loads to prevent adhesive wear of crankshaft of a high-torque low-speed diesel engine. The nominal clearance between the shaft-pin and the bearing journal invites viscous shearing of the lubricant on the initiation of rotation at the time of low speed engine start up. Shear heating adversely affects the load carrying ability of the bearing by reducing its viscosity as a function of time. It invites physical contact and wear of bearing and the crankshaft compromising their designed life. In this work the 2-D Reynolds equation is used to model hydrodynamic lubrication phenomenon of crankshaft covering the steady state wedging and transient squeeze which are modeled under the lubricant flooding conditions. The viscous shear heating is modeled by solving energy equation encompassing 2-D convection and 1-D conduction phenomena. The lateral displacements are incorporated in the lubrication model to analyze the effects of secondary dynamics of crankshaft on viscous shearing and friction. The relationships between temperature, viscosity and density are defined to ascertain their effects on bearing lubrication at low engine speed. The numerical simulation results are analyzed for the complete 720-degree 4-stroke engine cycle at a low operating speed. The results show that viscous heating adversely affects the lubrication of journal bearing by significantly reducing the viscosity of lubricant film at low transient loads and speed. The study determines hydrodynamic pressures, temperature, density, viscosity and thermal conductivity of lubricant suitable to minimize the possibility of rupture and adhesive wear due to shear heating under the flooding conditions at a low initial engine speed. It will facilitate towards enhancing the life of crankshaft of a heavy-duty diesel engine.

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.

Experimental Investigation of Mechanism of Lubrication in Porous Journal Bearings: Part 1—Observation of Oil Flow in Porous Matrix

1990 ◽  
Vol 112 (4) ◽  
pp. 618-623 ◽  
Author(s):  
S. Kaneko ◽  
S. Obara
Keyword(s):  
Hydrodynamic Lubrication ◽  
Porous Matrix ◽  
Journal Bearings ◽  
Feed Pressure ◽  
Glass Spheres ◽  
Load Line ◽  
Oil Flow ◽  
Uniform Diameter ◽  
Lubrication Conditions ◽  
Oil Film Pressure

The oil flow in the porous matrix is experimentally investigated to explicate the mechanism of lubrication in the porous journal bearings. To visualize the flow in the porous matrix, a simplified model is used for the test bearing, whose matrix is composed of packed glass spheres having small uniform diameter. A dye-injection method is used for visualization. It is observed that there exists a circulation of oil through the porous matrix and this flow contributes to the lubrication in the porous bearings. The flow pattern is dependent on the lubrication conditions. Under hydrodynamic lubrication conditions, the oil in the porous matrix flows away from the position of the load line towards the unloaded region. However under boundary lubrication conditions, when the oil feed pressure is negligibly small, most of the oil in the porous matrix flows toward the region where the oil film pressure would take the minimum.

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.

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