Research on the Status of Lubricating Oil Transport in Piston Skirt-Cylinder Liner of Engine

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Jun Sun ◽  
Xiang Huang ◽  
Guangsheng Liu ◽  
Xiaoyong Zhao ◽  
Enming Miao ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Cylinder Liner ◽  
Lubricating Oil ◽  
Engine Load ◽  
Piston Skirt ◽  
Oil Transport ◽  
Bottom Dead Center ◽  
The Status ◽  
Intake Stroke ◽  
Engine Operating Condition

The status of the lubricating oil transport in the piston skirt-cylinder liner has important influence on the lubrication of piston assembly frictional pair, the consumption of lubricating oil, the emission, and the performance degradation of lubrication oil. In this paper, based on the model of piston secondary motion, fluid lubrication and lubricating oil flow, the status of the lubricating oil transport between the piston skirt and the cylinder liner on different engine operating condition is calculated, and the quantity of lubricating oil retained on the surface of cylinder liner is mainly analyzed when the piston skirt moves from the top dead center to the bottom dead center. The results show that the variation of the quantity of retained lubricating oil is almost same in the corresponding stroke on different engine operating condition; the quantity of retained lubricating oil is dissimilar at different moment and is equal in principle at the piston top and bottom dead center. The quantity of lubricating oil retention is dissimilar at different moment in the intake stroke or expansion stroke, but the quantity of lubricating oil retention is equal in principle at the top and bottom dead center on different engine operating condition. When the engine is on the same load condition, as the engine rotational speed increasing, the quantity of retained lubricating oil is decreased in the whole intake stroke and the middle and later parts of expansion stroke, but the quantity of retained lubricating oil is increased in the front part of expansion stroke. When the engine is on the same rotational speed condition, the quantity of retained lubricating oil increases with the increasing engine load in the front part of expansion stroke, it does not vary with the engine load in principle in the middle and later part of expansion stroke, the variation that the quantity of retained lubricating oil varies with the engine load is dissimilar in the intake stroke on different engine rotational speed condition.

Research on the lubrication performance of engine piston skirt–cylinder liner frictional pair considering lubricating oil transport

2018 ◽  
Vol 21 (4) ◽  
pp. 713-722 ◽  
Author(s):  
Jun Sun ◽  
Feifei Hao ◽  
Guangsheng Liu ◽  
Hu Wang ◽  
Qin Teng ◽  
...  
Keyword(s):  
Cylinder Liner ◽  
Lubricating Oil ◽  
Frictional Pair ◽  
Operating Cycle ◽  
Piston Skirt ◽  
Oil Transport ◽  
Bottom Dead Center ◽  
Lubrication Performance ◽  
Oil Flow ◽  
Secondary Motion

In current lubrication analysis of piston skirt, the flooded status is generally considered in the piston skirt–cylinder liner frictional pair in all strokes of an engine operating cycle. However, the quantity of lubricating oil at the entrance of piston skirt cannot always ensure the sufficient lubrication status of piston skirt–cylinder liner frictional pair when the piston moves from the bottom dead center to the top dead center in actual engine. In this article, based on the model of piston secondary motion, fluid lubrication, and lubricating oil flow, the lubrication performance of piston skirt–cylinder liner frictional pair is analyzed, in which the quantity of lubricating oil detained on the surface of cylinder liner after the piston skirt moves from the top dead center to the bottom dead center and is considered as the quantity of lubricating oil at entrance of piston skirt when the piston moves from the bottom dead center to the top dead center. The results show that compared with current analysis, in which the sufficient lubrication of piston skirt–cylinder liner frictional pair is assumed in all strokes of engine, there are remarkable changes for the lubrication performance of piston skirt–cylinder liner frictional pair and the piston secondary motion when the lubrication status of the frictional pair in the upstroke of piston is determined by considering actual lubricating oil transport in the lubrication analysis of piston skirt.

Impact of the Piston Secondary Motion on its Slap Force

2014 ◽  
Vol 553 ◽  
pp. 582-587
Author(s):  
Bao Cheng Zhang ◽  
Tong Li ◽  
Hai Fei Zhan ◽  
Yuan Tong Gu
Keyword(s):  
Theoretical Model ◽  
Boundary Conditions ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Lubricating Oil ◽  
Actual Condition ◽  
Piston Skirt ◽  
Secondary Motion

A theoretical model is developed for the analysis of piston secondary motion. Based on this model, the slap force of a specific L6 diesel engine was compared when considering different boundary conditions, such as lubricating oil on cylinder liner, surface roughness, deformation of cylinder liner and piston skirt. It is concluded that it is necessary to consider the secondary motion of piston in the analysis of the inner excitation for an internal combustion engine. A more comprehensive consideration of the boundary condition (i.e., more close to the actual condition) will lead to a smaller maximum slap force, and among all boundary conditions considered in this paper, the structural deformation of the piston skirt and cylinder liner is the most influential factor. The theoretical model developed and findings obtained in this study will benefit the future analysis and design of advanced internal combustion engine structures.

Tribological evaluation of piston skirt/cylinder liner contact interfaces under boundary lubrication conditions

2010 ◽  
Vol 22 (3) ◽  
pp. 73-87 ◽  
Author(s):  
Nicholaos G. Demas ◽  
Robert A. Erck ◽  
George R. Fenske
Keyword(s):  
Boundary Lubrication ◽  
Cylinder Liner ◽  
Piston Skirt ◽  
Lubrication Conditions

Improvements in premixed charge compression ignition combustion and emissions with lower distillation temperature fuels

2005 ◽  
Vol 6 (5) ◽  
pp. 433-442 ◽  
Author(s):  
A Sakai ◽  
H Takeyama ◽  
H Ogawa ◽  
N Miyamoto
Keyword(s):  
Diesel Fuel ◽  
Direct Injection ◽  
Cylinder Liner ◽  
Lubricating Oil ◽  
Compression Ignition ◽  
Gas Temperature ◽  
Compression Stroke ◽  
Charge Mixture ◽  
Rate Of Heat Release ◽  
Wall Wetting

The charge mixture in a premixed charge compression ignition (PCCI) engine with direct in-cylinder injection early in the compression stroke is still heterogeneous even at the compression end. Direct injection of a low-volatility fuel, such as diesel fuel, early in the compression stroke results in adhesion of unevaporated fuel on the cylinder liner wall. It may be possible to improve both mixture formation and homogeneity, and decrease wall wetting by using higher-volatility fuels with distillation temperatures lower than the in-cylinder gas temperature early in the compression stroke. This research addressed the potential for improvements in early direct injection type PCCI combustion with a higher-volatility fuel, experimentally and computationally. A normal heptane + isooctane blended fuel with ignitability similar to diesel fuel in PCCI operation was used as the higher-volatility fuel. The experimental results showed that the deterioration in thermal efficiency that occurs with advanced injection timings with ordinary diesel fuel could be eliminated with the higher-volatility fuel without significantly altering the total hydrocarbons (THC) and CO emissions. With early injection timings, the rate of heat release with diesel fuel is smaller than with higher-volatility fuels. This result suggests that with diesel fuel there is significant fuel adhesion to the cylinder liner wall and also absorption into the lubricating oil.

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