The Prediction of Gas Pressures within the Ring Packs of Large Bore Diesel Engines

1981 ◽  
Vol 23 (6) ◽  
pp. 295-304 ◽  
Author(s):  
B. L. Ruddy ◽  
D. Dowson ◽  
P. N. Economou
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Angular Displacement ◽  
Cylinder Liner ◽  
Wall Friction ◽  
Piston Rings ◽  
Ring Pack ◽  
Piston Ring Lubrication ◽  
Volume Method ◽  
Gas Pressures

The established orifice and volume method for predicting the gas pressures between piston rings in reciprocating machines is extended to take account of the energy loss due to wall friction in the circumferential gas flow between the piston and cylinder liner. The results show that such energy losses are significant when gas flow rates exceed 10-2 kg/s and that this is most likely to occur in engines of over 0·5 m bore with worn piston rings. Under these conditions the angular displacement of the ring gaps significantly affects ring pack gas flow. In particular, it is shown that the maximum resistance to the flow of gas through the ring pack occurs when adjacent ring gaps are separated by more than 90 degrees. In the analysis of piston ring lubrication in ring packs it is necessary to ascertain the inter-ring pressures and the present paper enables such pressures to be determined with greater accuracy and for a wider range of engines.

scholarly journals Numerical analysis of piston ring pack operation

2009 ◽  
Vol 137 (2) ◽  
pp. 128-141
Author(s):  
Andrzej WOLFF
Keyword(s):  
Mathematical Model ◽  
Gas Flow ◽  
Piston Ring ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Labyrinth Seal ◽  
Piston Rings ◽  
Oil Film ◽  
Piston Ring Pack ◽  
Ring Pack

In the paper a model of a piston ring pack motion on an oil film has been analysed. The local oil film thickness can be compared to height of the combined roughness of mating surfaces of piston rings and cylinder liner. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng [6, 7] and Greenwood, Tripp [3] have been combined [12] and used in this paper. A model of a gas flow through the labyrinth seal of piston rings has been developed [13, 15]. In addition models of ring twist effects and axial ring motion in piston grooves have been applied [14, 15]. In contrast to the previous papers of the author, an experimental verification of the main parts of developed mathematical model and software has been presented. A relatively good compatibility between the experimental measurements and calculated results has been achieved. In addition this study presents the simulation results for an automobile internal combustion engine

scholarly journals Influence of piston ring pack configuration on blowby and friction losses in a marine two-stroke engine

2017 ◽  
Vol 170 (3) ◽  
pp. 164-170
Author(s):  
Andrzej WOLFF
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Labyrinth Seal ◽  
Piston Rings ◽  
Marine Engine ◽  
Oil Film ◽  
Flow Through ◽  
Piston Ring Pack ◽  
Ring Pack

In the paper a comprehensive model of a piston ring pack motion on an oil film has been presented. The local thickness of the oil film can be compared to height of the combined surface roughness of a cylinder liner and piston rings. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been combined and used in this paper. In addition a model of gas flow through the labyrinth seal of piston rings has been developed. The main parts of the model and software have been experimentally verified abroad by the author at the marine engine designing centre. For the selected two-stroke marine engine, the influence of the number of piston rings used and the type of the top ring lock (straight or overlapped) on blowby to piston underside and on friction losses of the piston-ring-cylinder (PRC) system have been investigated. The developed model and software can be useful for optimization of the PRC system design

scholarly journals Mathematical Model of Piston Ring Sealing in Combustion Engine

2015 ◽  
Vol 21 (4) ◽  
pp. 66-78 ◽  
Author(s):  
Grzegorz Koszałka ◽  
Mirosław Guzik
Keyword(s):  
Mathematical Model ◽  
Heat Exchange ◽  
Numerical Solution ◽  
Gas Flow ◽  
Piston Ring ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Computer Application ◽  
Piston Rings ◽  
Flow Through

Abstract This paper presents a mathematical model of piston-rings-cylinder sealing (TPC) of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit, displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls, were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model, the model itself, its numerical solution as well as its computer application for carrying out simulation tests.

scholarly journals Engine Speed and Load on the Sealing Capacity of a Piston Ring-Pack

2020 ◽  
Vol 5 (3) ◽  
pp. 304-313
Author(s):  
Erjon Selmani ◽  
Arian Bisha
Keyword(s):  
Gas Dynamics ◽  
Gas Flow ◽  
Piston Ring ◽  
Engine Speed ◽  
Fuel Mixture ◽  
Sealing Capacity ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Two Parameters ◽  
Gas Pressures

The combustion chamber is ought to be perfectly sealed, however, part of the air and fuel mixture can escape from it. Among the several losses there is the gas flow from the inter-ring crevices, which is always present. This leakage is known as blow-by, and affects efficiency, correct lubrication and emissions. The amount of leakage is dependent on many factors, and among the most important are the engine speed and load, which are able to affect the system through the forces applied on it. The aim of this paper was to understand in a more detailed way how the engine speed and load could affect the sealing efficiency of a ring-pack. For this purpose, a complete range of speeds and loads were used in the simulations. The equations of the ring motions and gas dynamics has been implemented and solved in ©Ricardo RINGPAK solver. The results showed that inertia and inter-ring gas pressures drives the sealing behavior of the rings. The blow-by trend showed to decrease with the speed and increase with the load, exception made for the idle condition where the values were different to the other cases, especially at higher speeds. Among the two parameters, the engine speed resulted to affect more significantly the blow-by trend.

Gas flow through the piston ring pack

2018 ◽  
Author(s):  
Petr Veigend ◽  
Gabriela Necasov ◽  
Peter Raffai ◽  
Vclav Åtek ◽  
Jir Kunovsk
Keyword(s):  
Gas Flow ◽  
Piston Ring ◽  
Flow Through ◽  
Piston Ring Pack ◽  
Ring Pack

scholarly journals Wear of different material pairings for the cylinder liner – piston ring contact

2018 ◽  
Vol 70 (4) ◽  
pp. 687-699 ◽  
Author(s):  
Thomas Wopelka ◽  
Ulrike Cihak-Bayr ◽  
Claudia Lenauer ◽  
Ferenc Ditrói ◽  
Sándor Takács ◽  
...  
Keyword(s):  
Steady State ◽  
Wear Mechanisms ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Wear Behaviour ◽  
Special Focus ◽  
Intermediate Step ◽  
Piston Rings ◽  
Content Type ◽  
Cylinder Liners

Purpose This paper aims to investigate the wear behaviour of different materials for cylinder liners and piston rings in a linear reciprocating tribometer with special focus on the wear of the cylinder liner in the boundary lubrication regime. Design/methodology/approach Conventional nitrided steel, as well as diamond-like carbon and chromium nitride-coated piston rings, were tested against cast iron, AlSi and Fe-coated AlSi cylinder liners. The experiments were carried out with samples produced from original engine parts to have the original surface topography available. Radioactive tracer isotopes were used to measure cylinder liner wear continuously, enabling separation of running-in and steady-state wear. Findings A ranking of the material pairings with respect to wear behaviour of the cylinder liner was found. Post-test inspection of the cylinder samples by scanning electron microscopy (SEM) revealed differences in the wear mechanisms for the different material combinations. The results show that the running-in and steady-state wear of the liners can be reduced by choosing the appropriate material for the piston ring. Originality/value The use of original engine parts in a closely controlled tribometer environment under realistic loading conditions, in conjunction with continuous and highly sensitive wear measurement methods and a detailed SEM analysis of the wear mechanisms, forms an intermediate step between engine testing and laboratory environment testing.

Field-Testing of Biodiesel (B100) and Diesel-Fueled Vehicles: Part 3—Wear Assessment of Liner and Piston Rings, Engine Deposits, and Operational Issues

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Avinash Kumar Agarwal ◽  
Deepak Agarwal
Keyword(s):  
Piston Ring ◽  
Direct Injection ◽  
Cylinder Liner ◽  
Field Testing ◽  
Field Trials ◽  
Operating Conditions ◽  
Piston Rings ◽  
Carbon Deposits ◽  
Bottom Dead Center ◽  
Operational Issues

Abstract This study investigated the use of biodiesel (B100) and baseline mineral diesel in two identical unmodified vehicles to realistically assess different aspects of biodiesel’s compatibility and durability issues with modern common rail direct injection (CRDI) engine-powered vehicles. Two identical vehicles were operated for 30,000 km under identical operating conditions during a field-trial using biodiesel (B100) and mineral diesel. Exhaustive experimental results from this series of tests are divided into four sections, and this is the third paper of this series of four papers, which covers comparative feasibility and wear analyses, underlining the effect of long-term use of biodiesel on wear of cylinder liner and piston rings compared to baseline mineral diesel-fueled vehicle. Surface microstructures at three locations of the cylinder liner were evaluated using scanning electron microscopy (SEM). Wear was found to be relatively lower at all locations of liners from biodiesel-fueled vehicle compared to diesel-fueled vehicle. Surface roughness of cylinder liners measured at different locations showed that it reduced by ∼30–40% at top dead center (TDC), ∼10–20% at mid-stroke, and ∼20–30% at bottom dead center (BDC) for both vehicles, showing higher wear close to TDC compared to mid-stroke and BDC locations. Loss of piston-ring weight was significantly lower for biodiesel-fueled vehicle. Engine tear-down observations and carbon deposits on various engine components were recorded after the conclusion of the field trials. During these field-trials, engine durability-related issues such as fuel-filter plugging, injector coking, piston-ring sticking, carbon deposits in the combustion chamber, and contamination of lubricating oils were found to be relatively lower in biodiesel-fueled vehicle. Overall, no noticeable durability issues were recorded because of the use of biodiesel in CRDI engine-powered vehicle.

Simulation of Altitude Influence on Piston Ring Movement and Blow-By Effects in Piston Engines (Keynote)

2003 ◽  
Author(s):  
Sylvester Abanteriba
Keyword(s):  
Combustion Chamber ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Lubricating Oil ◽  
Axial Position ◽  
Piston Engine ◽  
Piston Rings ◽  
Ability To Act ◽  
Effective Seal ◽  
The Impact

The compression and oil rings of the piston engine play a very important role in the performance and reliability of the piston engine. The rings are required to accomplish three main distinct tasks: 1. Sealing the combustion chamber gas from the crankcase to eliminate blow-by phenomenon, which constitutes the flow of some of the contents of the combustion chamber into the crankcase. 2. Proper distribution of the lubricating oil film over the piston skirt and cylinder liner. 3. Transfer of heat from piston to cylinder liner. Unfortunately the piston ring pack contributes to the highest proportion of the frictional losses in the engine and is more prone to high wear rates. In the engine, the compression rings are designed to provide effective sealing of the crankcase against the gases from the combustion chamber. The oil-rings provide an effective means of distributing the lubricating oil over the cylinder liner while keeping it from flowing into the combustion chamber. The ability of the compression rings to serve as a gas seal depends on their axial position within the groove. The ring needs to be in contact with the lower flank in order to provide the requisite sealing effect. Once the ring lifts itself from the lower flank its ability to act as an effective seal is compromised. The axial motion of the piston rings during the operation of the engine engenders blow-by and therefore has deteriorating effect on the engine performance. Not much work has, hereto, been done to study the impact of altitude on the movement of the piston rings and hence the blow-by phenomenon. This papers presents a simulation model to investigate this effect.

scholarly journals ANALISIS PERUBAHAN KEKERASAN YANG TERJADI PADA CINCIN TORAK AKIBAT PERUBAHAN JARAK TEMPUH PADA MOTOR YAMAHA MIO SOUL GT

2021 ◽  
pp. 32-37
Keyword(s):  
Combustion Chamber ◽  
Change Process ◽  
Fracture Process ◽  
Piston Ring ◽  
Combustion Engine ◽  
Energy Transfer Process ◽  
Piston Rings ◽  
Stiff Material ◽  
Piston Ring Lubrication

In a four stroke combustion engine, there are three piston rings, namely two compression piston rings and one lubrication control piston ring. The piston compression ring serves to maintain the combustion pressure, while the piston ring lubrication regulator functions to lubricate the combustion chamber during the energy change process so that the piston will run back and forth in the combustion chamber smoothly. Damage that occurs to the piston ring can be in the form of a broken piston ring, or a scratched or worn piston ring. These things can reduce the quality of the energy transfer process. The piston ring is broken because the ring is too brittle. Vibration that occurs in the piston when combustion occurs at full load increases the possibility of a fracture process in the piston ring. The brittleness of the piston ring is strongly influenced by the material used. To overcome this, a hard but not stiff material is needed. Keywords: Hardness, mileage, Vicker test

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