scholarly journals Geometry of shape of profiles of the sliding surface of ring seals in the aspect of friction losses and oil film parameters

2016 ◽  
Vol 167 (4) ◽  
pp. 38-52 ◽  
Author(s):  
Piotr WRÓBLEWSKI ◽  
Antoni ISKRA

The article describes the results of simulations of the approved variations of sliding surfaces of ring seals in relation to a reference symmetrical barrel profile which is most often used in piston internal combustion engines. In particular the paper discusses the impact of the five assumed variants of sliding profiles of ring seals onto the thickness of oil film left on the cylinder face by a bottom and upper ring seal, the distribution of internal friction force in oil film between the ring seal set and the cylinder face, finally the oil film cover on a sliding surface of the upper ring seal. The results presented in the article show a close relationship between the sliding surface profile of ring seals and a unit oil consumption. A relationship between these parameters for the elements lying in the movement plane of a wrist pin axis was proven, as well as for the one lying in the plane perpendicular to it. Exemplary parameters of oil film and friction losses were presented while assuming a constant total axial values of the height and depth of circumferential grooves. The shapes of these grooves on the sliding surface of the ring seals in free state can be made with electroerosion microprocessing or ablative laser microprocessing.

2005 ◽  
Vol 127 (1) ◽  
pp. 206-212
Author(s):  
T. Icoz ◽  
Z. Dursunkaya

Blowback of engine oil suspended in combustion gases, when the gas flows from the piston second land back into the combustion chamber, is believed to contribute to oil consumption and hydrocarbon emissions in internal combustion engines. Oil accumulation in the region between top and second compression rings is a factor that influences this phenomenon. The effects of individual parameters, such as oil film thickness and viscosity, however, have still not been understood. The present study was aimed at constructing an experimental setup to study the effect of oil film thickness on oil accumulation in the second land of internal combustion engines. Due to the inherent difficulties of experimentation on production engines, a modeled piston-cylinder assembly was constructed. Total oil accumulation in the modeled second land after a single piston stroke was measured and compared to oil consumption in operating engines.


Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7492
Author(s):  
Vincent Berthome ◽  
David Chalet ◽  
Jean-François Hetet

Particulate emission from internal combustion engines is a complex phenomenon that needs to be understood in order to identify its main factors. To this end, it appears necessary to study the impact of unburned gases, called blow-by gases, which are reinjected into the engine intake system. A series of transient tests demonstrate their significant contribution since the particle emissions of spark-ignition engines are 1.5 times higher than those of an engine without blow-by with a standard deviation 1.5 times greater. After analysis, it is found that the decanter is not effective enough to remove completely the oil from the gases. Tests without blow-by gases also have the advantage of having a lower disparity, and therefore of being more repeatable. It appears that the position of the “endgap” formed by the first two rings has a significant impact on the amount of oil transported towards the combustion chamber by the backflow, and consequently on the variation of particle emissions. For this engine and for this transient, 57% of the particulate emissions are related to the equivalence ratio, while 31% are directly related to the ability of the decanter to remove the oil of the blowby gases and 12% of the emissions come from the backflow. The novelty of this work is to relate the particles fluctuation to the position of the endgap ring.


2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Mohamed Kamal Ahmed Ali ◽  
Hou Xianjun

AbstractThe friction between two sliding surfaces is probably one of the oldest problems in mechanics. Frictional losses in any I.C. engine vary between 17% and 19% of the total indicated horse power. The performance of internal combustion engines in terms of frictional power loss, fuel consumption, oil consumption, and harmful exhaust emissions is closely related to the friction force and wear between moving parts of the engine such as piston assembly, valve train, and bearings. To solve this problem, most modern research in the area of Nanotribology (Nanolubricants) aims to improve surface properties, reduce frictional power losses, increase engine efficiency, and reduce consumed fuel and cost of maintenance. Nanolubricants contain different nanoparticles such as Cu, CuO, TiO


2020 ◽  
Vol 10 (11) ◽  
pp. 3705
Author(s):  
Ahmad Alshwawra ◽  
Florian Pohlmann-Tasche ◽  
Frederik Stelljes ◽  
Friedrich Dinkelacker

Reducing friction is an important aspect to increase the efficiency of internal combustion engines (ICE). The majority of frictional losses in engines are related to both the piston skirt and piston ring–cylinder liner (PRCL) arrangement. We studied the enhancement of the conformation of the PRCL arrangement based on the assumption that a suitable conical liner in its cold state may deform into a liner with nearly straight parallel walls in the fired state due to the impact of mechanical and thermal stresses. Combining the initially conical shape with a noncircular cross section will bring the liner even closer to the perfect cylindrical shape in the fired state. Hence, a significant friction reduction can be expected. For the investigation, the numerical method was first developed to simulate the liner deformation with advanced finite element methods. This was validated with given experimental data of the deformation for a gasoline engine in its fired state. In the next step, initially conically and/or elliptically shaped liners were investigated for their deformation between the cold and fired state. It was found that, for liners being both conical and elliptical in their cold state, a significant increase of straightness, parallelism, and roundness was reached in the fired state. The combined elliptical-conical liner led to a reduced straightness error by more than 50% compared to the cylindrical liner. The parallelism error was reduced by 60% to 70% and the roundness error was reduced between 70% and 80% at different liner positions. These numerical results show interesting potential for the friction reduction in the piston-liner arrangement within internal combustion engines.


2019 ◽  
Vol 11 (23) ◽  
pp. 6585 ◽  
Author(s):  
Markiewicz ◽  
Muślewski

The application of fuels from renewable energy sources for combustion engine powering involves a great demand for this kind of energy while its production infrastructure remains underdeveloped. The use of this kind of fuel is supposed to reduce the emission of greenhouse gases and the depletion of natural resources and to increase the share of renewable energy sources in total energy consumption and thus support sustainable development in Europe. This study presents the results of research on selected performance parameters of transport by internal combustion engines including: power, torque, the emission of sound generated by the engine, the content of exhaust components (oxygen O2, carbon monoxide CO, carbon dioxide CO2, nitrogen dioxide NO2), and the content of particulate matter (PM) in exhaust emission. Three self-ignition engines were tested. The fuel injection controllers of the tested internal combustion engines were additionally adjusted by increasing the fuel dose and the load of air. The material used in the tests were mixtures of diesel oil and fatty acid methyl esters of different concentration. A statistical analysis was performed based of the results. The purpose of the work was to develop a resulting model for assessing the operation of engines fueled with biofuel and diesel mixtures while changing the vehicle's computer software. A computer simulation algorithm was also developed for the needs of the tests which was used to prognose the state of the test results for variable input parameters.


Author(s):  
Cristiana Delprete ◽  
Abbas Razavykia

Internal combustion engines are at present used as the major power sources for transportation and power generator. Improvement of the internal combustion engine efficiency is expected due to strict environmental standards and energy costs. Any reduction in oil consumption, friction power losses and emissions results in improving engines’ performance and durability. Automotive industries have intense passion to increase engines’ efficiency to meet the fuel economy and emission standards. Many studies have been conducted to develop reliable approaches and models to understand the lubrication mechanisms and calculate power losses. This review paper summarizes the synthesis of the main technical aspects considered during modeling of piston ring–liner lubrication and friction losses investigations. The literature review highlights the effects of piston ring dynamics, components geometry, lubricant rheology, surface topography and adopted approaches, on frictional losses contributed by the piston ring-pack.


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