scholarly journals Effects of Bearing Steps on Probable Wear Damage of Main Bearings of an IC Engine

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
H. Karimaei ◽  
H. R. Chamani
Keyword(s):  
Hydrodynamic Model ◽  
Mass Conservation ◽  
Main Bearing ◽  
Ic Engine ◽  
Oil Film ◽  
Lubrication Performance ◽  
Lubrication Characteristics ◽  
Wear Damage ◽  
Assembly Error ◽  
Oil Film Pressure

When two bearing shells are assembled in the bearing housing, it is possible that the edges of the two shells do not fit in the radial direction completely and have an offset relative to each other. This assembly error, which can have different causes, is called the bearing step in this paper. The bearing step can lead to wear damage in bearings. The effects of bearing step on the lubrication performance of main bearings and the probable wear damage have been investigated. To calculate the bearing lubrication characteristics such as maximum oil film pressure and minimum oil film thickness, elasto-hydrodynamic model, which includes the mass conservation algorithm, has been applied. The objective of this work is to investigate the effects of bearing steps on the lubrication performance of the main bearings and assess the probable wear damage of main bearings due to bearing step. The prediction of elasto-hydrodynamic model is very proximate to what really happened. The results show that for the under-study 12-cyl engine, main bearing No. 2 involved with medium wear damage. Wear damage in this main bearing No. 3 is not a concern, while main bearing No.4, 5 and 6 do not predict the probability of wear damage. For main bearing No.7, it is concluded that considering step and bore relief in simulation has high importance so that the solution without step and bore relief does not predict the wear, but with step and bore relief predicts medium wear damage.

Full Shafting-Based Elastohydrodynamic Lubrication Simulation for Main Bearings of Marine Diesel Engine

2012 ◽  
Vol 479-481 ◽  
pp. 1119-1123 ◽  
Author(s):  
Hui Xing ◽  
Hui Zhang ◽  
Qili Wu ◽  
Shu Lin Duan
Keyword(s):  
Diesel Engine ◽  
Marine Diesel Engine ◽  
Main Bearing ◽  
Film Pressure ◽  
Oil Film ◽  
Marine Diesel ◽  
Simulation Results ◽  
Lubrication Characteristics ◽  
The Impact ◽  
Oil Film Pressure

To predict and analyze accurately the lubrication characteristics and its influencing factors of main bearing for large low-speed two-stroke marine diesel engine, based on EHD lubrication model of dynamically loaded bearing, coupling simulation between EHD and MBD for main bearing of marine diesel engine was carried out. Systemic models were established separately considering the independent crankshaft of diesel engine and the full shafting of propulsion power plant. Main bearing load, peak oil film pressure, oil film pressure distribution, MOFT and orbital path in one working cycle under rated working conditions were investigated, and simulation results were compared based on both models. The results show that, if the impact of full shafting was considered, the lubrication characteristics of No.8 main bearing changed significantly, the lubrication characteristics of other main bearings were similar as the simulation results of the independent crankshaft model.

The effects of material and structure of main bearing caps on crankshaft lubrication of diesel engine

2020 ◽  
pp. 146808741989664
Author(s):  
Limin Wu ◽  
Yan Fu ◽  
Mei Li ◽  
Gang Liang ◽  
Yanting Zhang ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Coupled Model ◽  
Engine Block ◽  
Main Bearing ◽  
Film Pressure ◽  
Oil Film ◽  
Medium Speed ◽  
Lubrication Performance ◽  
Bearing Cap ◽  
Oil Film Pressure

The elastic deformation of the crankshaft and engine block has important effects on lubrication performance of main bearings of the diesel engine. But the effect of main bearing caps was rarely analyzed. The purpose of this article is to analyze and compare the tribological performances of main bearings of a 20-V medium-speed diesel engine with different materials and structures of main bearing caps. A coupled multi-elastic body and elasto-hydrodynamic model is established for a 20-V medium-speed diesel engine. The deformations of engine block, crankshaft and bearing caps are simulated with finite element modal condensation method. The bearing lubrication analysis is based on the extended Reynolds equation considering the deformation of contact surface and solved by finite difference method. Two materials and four structures of the main bearing cap are analyzed with the coupled model. The distribution of oil film pressure, thickness and bearing thermal loads are obtained and analyzed. The main bearing cap of iron is better than steel on bearing lubrication performance. With the lower edge stiffness of bearing cap, the maximum oil film pressure of bearing can be reduced by 13%. Meanwhile, the bearing thermal load can be reduced by 53%. The results show that when the bearing cap material is iron and with large trough on both sides of bearing cap, the peak value of edge pressure and the average heat load of main bearing can be reduced effectively under the premise of ensuring stiffness.

Effect of recess depth on lubrication performance of annular recess hydrostatic thrust bearing by constant rate flow

2018 ◽  
Vol 70 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Jun-peng Shao ◽  
Guang-dong Liu ◽  
Xiao-dong Yu ◽  
Yan-qin Zhang ◽  
Xiu-li Meng ◽  
...  
Keyword(s):  
Thrust Bearing ◽  
Simulation Method ◽  
Content Type ◽  
Oil Film ◽  
Constant Rate ◽  
Lubrication Performance ◽  
Optimal Value ◽  
Improved Performance ◽  
Lubrication Characteristics ◽  
Volume Method

Purpose The purpose of this paper is to describe a simulation and experimental research concerning the effect of recess depth on the lubrication performance of a hydrostatic thrust bearing by constant rate flow. Design/methodology/approach The computational fluid dynamics and finite volume method have been used to compute the lubrication characteristics of an annular recess hydrostatic thrust bearing with different recess depths. The performances are oil recess pressure, oil recess temperature and oil film velocity. The recess depth has been optimized. A test rig is established for testing the pressure field of the structure of hydrostatic thrust bearing after recess depth optimization, and experimental results show that experimental data are basically identical with the simulation results, which demonstrates the validity of the proposed numerical simulation method. Findings The results demonstrate that the oil film temperature decreases and the oil film pressure first increases and then decreases with an increase in the recess depth, but oil film velocity is constant. To sum up comprehensive lubrication performance, the recess depth of 3.5 mm is its optimal value for the annular recess hydrostatic thrust bearing. Originality/value The computed results indicate that to get an improved performance from a constant flow hydrostatic thrust bearing, a proper selection of the recess depth is essential.

Fibre Optic Sensors for Long-Term Monitoring of Oil Film Pressure in Diesel Engine Main Bearing

2014 ◽  
Vol 56 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Markku Kapulainen ◽  
Helena Ronkainen ◽  
Ari Hokkanen ◽  
Ingmar Stuns ◽  
Simo Varjus ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fibre Optic ◽  
Main Bearing ◽  
Film Pressure ◽  
Oil Film ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Oil Film Pressure

An Experimental Study of Journal Bearing Lubrication Effected by Journal Misalignment as a Result of Shaft Deformation Under Load

2005 ◽  
Vol 127 (4) ◽  
pp. 813-819 ◽  
Author(s):  
Jun Sun ◽  
Changlin Gui ◽  
Zhiyuan Li
Keyword(s):  
Journal Bearing ◽  
Friction Pair ◽  
Obvious Effect ◽  
Oil Film ◽  
Lubrication Performance ◽  
Mechanical Devices ◽  
Journal Misalignment ◽  
Shaft Deformation ◽  
Oil Film Pressure ◽  
Bearing Friction

Journal bearing friction pair system is one of the most general and essential parts used in various mechanical devices. A special test bench is developed for the study on lubrication performance of cylindrical journal bearings. The effect of journal misalignment as a result of shaft bending under load is studied. The results show obvious changes at distribution and value of oil film pressure, oil film thickness and oil temperature of journal bearing due to journal misalignment. The higher the load on the shaft, the larger the journal misalignment resulted from shaft deformation, the more obvious effect on lubrication performance of journal bearing.

scholarly journals Marine Four-Stroke Diesel Engine Crankshaft Main Bearing Oil Film Lubrication Characteristic Analysis

2018 ◽  
Vol 25 (s2) ◽  
pp. 30-34
Author(s):  
Teng Xian Bin ◽  
Zhang Jun Dong
Keyword(s):  
Diesel Engine ◽  
Film Thickness ◽  
Dynamic Pressure ◽  
Synthesis Method ◽  
Elastohydrodynamic Lubrication ◽  
Characteristic Analysis ◽  
Main Bearing ◽  
Oil Film ◽  
Modal Synthesis ◽  
Lubrication Performance

Abstract The Craig-Bampton modal synthesis method was used to establish the dynamic model of marine four-stroke diesel engine body and crankshaft. Based on the Greenwood/Tripp microlong contact theory considering the surface roughness and the generalized Reynolds equation considering the oil filling rate, the elastohydrodynamic lubrication model of the main bearing of the four - stroke diesel engine is found. At the rated speed, the lubrication performance of the main bearing is simulated and analyzed by the maximum dynamic pressure, the minimum oil film thickness and the friction power. The results show that the oil pressure of 4 # main bearing is the largest and the maximum oil film pressure is in the 4 # main bearing position. The friction load of 4 # main bearing is the largest. The average oil film thickness of 4 # main bearing is the smallest and the minimum oil film The thickness also occurred in the 4 # main bearing position; it can be seen 4 # bearing the most bad lubrication conditions.

Study of Cavitation and Wear Damages in Conrod Big End Bearing of a Heavy Duty Diesel Engine by Using Elasto-Hydrodynamic Method

2009 ◽  
Author(s):  
Hadiseh Karimaei ◽  
Hamidreza Chamani
Keyword(s):  
Diesel Engine ◽  
Heavy Duty ◽  
Connecting Rod ◽  
Cavitation Damage ◽  
Oil Film ◽  
Heavy Duty Diesel Engine ◽  
Hydrodynamic Method ◽  
Heavy Duty Diesel ◽  
Wear Damage ◽  
Oil Film Pressure

Wear and cavitation erosion are the common damages in engine bearing shells. In the case of cavitation damage, the generation and immediate collapse of small gas bubbles cause high pressure pulses and the bearing surface is being locally damaged. Cavitation damage is observed in heavy duty diesel engine due to highly dynamic loading, oscillation of pins, turbulence of oil flow and other factors. Wear damage induces adjustment in the bearing geometry and affects the oil film pressure and the durability of bearing shell. In this paper, wear and cavitation damages in connecting rod big end bearing have been studied. In order to compute the bearing lubrication characteristic such as minimum oil film thickness and maximum oil film pressure, Elasto-Hydrodynamic method that incorporates mass conserving algorithm has been utilized. Wear and cavitation damages in two different designs of connecting rod structure in a heavy duty diesel engine have been assessed and the results have been presented. Furthermore, the effect of connecting rod structure on wear damage has been investigated.

Numerical study on lubrication performance of engine main bearing with rough surface considering axial movement of crankshaft

2019 ◽  
Vol 234 (1) ◽  
pp. 98-109
Author(s):  
Biao Li ◽  
Jun Sun ◽  
Shaoyu Zhu ◽  
Yangyang Fu ◽  
Enming Miao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Rough Surface ◽  
Numerical Study ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Main Bearing ◽  
Lubrication Performance ◽  
Axial Movement ◽  
Actual Operation ◽  
Lubrication Characteristics

In actual operation of an engine, the crankshaft will move along the axis direction of engine main bearings under the combined influence of various influencing factors. Considering the axial movement and crankshaft deformation, a new lubrication model of engine main bearings with rough surface was built based on the average Reynolds equation. The influence of axial movement of deformed crankshaft on performance of main bearing with rough surface was studied. In this study, the axial movement law of deformed crankshaft is measured through experiment, and the finite element method was applied to solve the tilting of crankshaft in the bearing bore resulted from the crankshaft deformation. The results show that the axial movement of deformed crankshaft has a significant impact on performance of main bearing with rough surface. No matter whether or not the surface roughness is considered, the journal center trajectories of main bearings are unclosed three-dimensional space curve due to the axial movement of deformed crankshaft. The influence level of the axial movement of deformed crankshaft on lubrication characteristics of main bearings is directly related to the surface roughness. The influence trend and level of the surface roughness on lubrication characteristics of main bearings are obviously changed when considering the axial movement of crankshaft.

Numerical analysis of the effects of compression ring wear and cylinder liner deformation on the thermal mixed lubrication performance of ring-liner system

2018 ◽  
Vol 19 (2) ◽  
pp. 203 ◽  
Author(s):  
Cheng Liu ◽  
Yanjun Lu ◽  
Peng Wang ◽  
Yongfang Zhang ◽  
Yonggui Zhang ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Thermal Effect ◽  
Cylinder Liner ◽  
Mass Conservation ◽  
Asperity Contact ◽  
Friction Forces ◽  
Oil Film ◽  
Compression Ring ◽  
Lubrication Performance ◽  
Liner System

The lubrication performance of roughness compression ring-cylinder liner system (CRCL) with axial-asymmetric new/worn compression ring and out-of-round cylinder liner is studied in this paper. By considering the oil film thermal effect, cavitation phenomenon, and surface roughness, the energy equations, mass conservation Jacoboson-Floberg-Olsson (JFO) cavitation algorithm, generalized average Reynolds equation, and Greenwood-Tripp asperity contact model are employed to investigate the frictional behaviors of CRCL. The oil film thickness, friction forces, wear, and power loss of CRCL are investigated at various wear stages of compression ring. The effects of the magnitude of cylinder liner deformation on the frictional characteristics of CRCL are also analyzed with consideration of compression ring conformability. Numerical results show that the deformation of cylinder liner and the wear of compression ring have a significant influence on the lubrication performance. It also suggests that the oil film thermal effect should be considered in the numerical analysis to provide an accurate prediction on the frictional behaviors of CRCL.

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