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.

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

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.

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.

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.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

Stress Distribution Analysis on Alloy Layer of High Power Marine Diesel Engine Bearing Bush

2013 ◽  
Vol 331 ◽  
pp. 148-152
Author(s):  
Xiu Xu Zhao ◽  
Zhi Xiang Hu ◽  
An Jian Huang
Keyword(s):  
Diesel Engine ◽  
High Power ◽  
Alloy Layer ◽  
Marine Diesel Engine ◽  
Oil Film ◽  
Marine Diesel ◽  
Bearing Alloy ◽  
Stress And Strain Distribution ◽  
Engine Bearing ◽  
Oil Film Pressure

According to the characteristics of large size, small clearance ratio, high oil film pressure and thin oil film thickness in the actual conditions of high power marine diesel engine bearing, this Paper analyzes oil film pressure distribution on inner surface of bearing bush based on the finite difference method, uses finite element method to establish the hierarchical model, and analyzes stress and strain distribution on bearing alloy. In addition, this Paper researches the changes of stress and strain distribution on bearing alloy layer when alloy layer thickness changes for the optimization design of high power marine diesel engine bearing bush.

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