Friction Reduction via Piston and Ring Design for an Advanced Natural-Gas Reciprocating Engine

2004 ◽  
Author(s):  
Grant Smedley ◽  
S. H. Mansouri ◽  
Tian Tian ◽  
Victor W. Wong
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Substantial Reduction ◽  
Friction Reduction ◽  
Design Parameters ◽  
Design Strategies ◽  
Low Friction ◽  
Piston Skirt ◽  
Model Predictions

Friction from the power cylinder represents a significant contribution to the total mechanical losses in internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel consumption, and reduced emissions. In this study, models incorporating piston ring dynamics and piston secondary motion with elastic skirt deformation were applied to a Waukesha natural gas power generation engine to identify the main contributors to friction within the piston and ring pack system. Based on model predictions, specific areas for friction reduction were targeted and low-friction design strategies were devised. The most significant contributors to friction were identified as the top ring, the oil control ring, and the piston skirt. Model predictions indicated that the top ring friction could be reduced by implementing a skewed barrel profile design or an upward piston groove tilt design, and oil control ring friction could be reduced by decreasing ring tension. Piston design parameters such as skirt profile, piston-to-liner clearance, and piston surface characteristics were found to have significant potential for the reduction of piston skirt friction. Designs were also developed to mitigate any adverse effects that were predicted to occur as a result of implementation of the low-friction design strategies. Specifically, an increase in wear was predicted to occur with the upward piston groove tilt design, which was eliminated by the introduction of a positive static twist on the top ring. The increase in oil consumption resulting form the reduction in the oil control ring tension was mitigated by the introduction of a negative static twist on the second ring. Overall, the low-friction design strategies were predicted to have potential to reduce piston ring friction by 35% and piston friction by up to 50%. This would translate to an improvement in brake thermal efficiency of up to 2%, which would result in a significant improvement in fuel economy and a substantial reduction in emissions over the life of the engine.

Piston dynamics, lubrication and tribological performance evaluation: A review

2018 ◽  
Vol 21 (5) ◽  
pp. 725-741 ◽  
Author(s):  
Cristiana Delprete ◽  
Abbas Razavykia
Keyword(s):  
Power Loss ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Tribological Performance ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Design Parameters ◽  
Combustion Engines ◽  
Piston Skirt ◽  
Secondary Motion

Mechanical power loss of lubricated and bearing surfaces serves as an attractive domain for study and research in the field of internal combustion engines. Friction reduction at lubricated and bearing surface is one of the most cost-effective ways to reduce gas emission and improve internal combustion engines’ efficiency. This thus motivates automotive industries and researchers to investigate tribological performance of internal combustion engines. Piston secondary motion has prime importance in internal combustion engines and occurs due to unbalanced forces and moments in a plane normal to the wrist pin axis. Consequently, piston executes small translations and rotations within the defined clearance during the piston reciprocating motion. Mechanical friction power loss and lubrication at piston skirt/liner and radiated engine noise are dramatically affected by piston secondary dynamics. The lubrication mechanism, piston secondary motion and tribological performance are affected by piston design parameters (piston/liner clearance, wrist pin offset, skirt profile, etc.), lubricant rheology, oil transport mechanism and operating conditions. Therefore, this review is devoted to summarize the synthesis of main technical aspects, research efforts, conclusions and challenges that must be highlighted regarding piston skirt/liner lubrication and piston dynamics and slap.

Advanced Tribological Assessment of Ring Coatings

2012 ◽  
Author(s):  
Max Maschewske ◽  
Kimm Karrip ◽  
Carol Lynn Deck
Keyword(s):  
Coefficient Of Friction ◽  
Surface Finish ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
Piston Ring ◽  
Friction Reduction ◽  
Bench Test ◽  
Test Rig ◽  
Frictional Characteristic ◽  
The Impact

Friction reduction within the power cylinder assembly of internal combustion engines continues to be a one of the foremost focuses of engine manufactures. In an effort to better address this topic previously developed bench test rigs, such as the Falex, Cameron-Plint, and EMA-LS9 [1,2], have been utilized. These devices were formerly focused solely on wear mechanisms and material compatibility. Current development of new piston ring coatings has demanded significant refinements to the previously mentioned EMA-LS9 test rig for specific frictional characteristic evaluations. These developments have allowed for coefficient of friction ranking between various piston ring materials in addition to the influence and surface finish on coefficient of friction. This paper examines how the test rig is utilized to characterize upper compression ring materials, surface treatments, and the impact of surface finish. The significance of these results will be examined as it applies to analytical evaluations. From these calculations a demonstration of the effect of surface finish on ring dynamics and gas flow, as well as future piston ring coating developments will be discussed.

An Integrated Model of Ring Pack Performance

1991 ◽  
Vol 113 (3) ◽  
pp. 382-389 ◽  
Author(s):  
R. Keribar ◽  
Z. Dursunkaya ◽  
M. F. Flemming
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Engine Speed ◽  
Integrated Model ◽  
Design Parameters ◽  
Combustion Engines ◽  
Predictive Tool ◽  
Engine Friction ◽  
Piston Ring Pack ◽  
Ring Pack

This paper describes an integrated model developed for the detailed characterization and simulation of piston ring pack behavior in internal combustion engines and the prediction of ring pack performance. The model includes comprehensive and coupled treatments of (1) ring-liner hydrodynamic and boundary lubrication and friction; (2) ring axial, radial, and (toroidal) twist dynamics; (3) inter-ring gas dynamics and blowby. The physics of each of these highly inter-related phenomena are represented by submodels, which are intimately coupled to form a design-oriented predictive tool aimed at the calculation of ring film thicknesses, ring motions, land pressures, engine friction, and blowby. The paper also describes the results of a series of analytical studies investigating effects of engine speed and load and ring pack design parameters, on ring motions, film thicknesses, and inter-ring pressures, as well as ring friction and blowby.

Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn 4-Stroke Natural Gas Engine: Experimental Results

2006 ◽  
Author(s):  
Kris Quillen ◽  
Rudolf H. Stanglmaier ◽  
Luke Moughon ◽  
Rosalind Takata ◽  
Victor Wong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Piston Ring ◽  
Department Of Energy ◽  
Experimental Results ◽  
Friction Reduction ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Computational Tools ◽  
Ring Pack ◽  
Institute Of Technology

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT) and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the US Department of Energy. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼ 0.50% improvement in mechanical efficiency (ηmech).

Influence of the Position of Oil Drain Holes of a Piston on Lubricating Oil Consumption

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Hiroki Hasegawa ◽  
Koji Kikuhara ◽  
Akemi Ito ◽  
Shunsuke Nishijima ◽  
Masatsugu Inui ◽  
...  
Keyword(s):  
Piston Ring ◽  
Gasoline Engine ◽  
Pressure Sensors ◽  
Lubricating Oil ◽  
Oil Consumption ◽  
Tracer Method ◽  
Low Friction ◽  
Piston Skirt ◽  
Generation Mechanisms ◽  
Good Agreement

An increase in lubricating oil consumption in a gasoline engine causes an increase in particulate matters in exhaust gases, poisoning the catalyst after treatment devices, abnormal combustion in a turbo-charged gasoline engine, and so on. Recent trend of low friction of a piston and piston ring tends to increase in lubricating oil consumption. Therefore, reducing oil consumption is required strongly. In this study, the effect of the position of oil drain holes on oil pressure under the oil ring and lubricating oil consumption was investigated. The oil pressure under the oil ring is measured using fiber optic pressure sensors and pressure generation mechanisms were investigated. Lubricating oil consumption was also measured using sulfur tracer method and the effects of oil drain holes hence the oil pressure were evaluated. Four types of arrangement of oil drain holes were tested. The oil pressure variations under the oil ring in the circumferential direction was measured. An increase in oil pressure was found during down-stroke of the piston. The lowest oil pressure was found for the piston with four oil drain holes. Two holes nearby the front/rear end of the piston skirt showed relatively lower pressure. The measured results of oil consumption showed good agreement to measured oil pressure under the oil ring. It was found that oil pressure under the oil ring affected oil consumption, and oil drain holes set near the front/rear end of the piston skirt were effective for reducing oil consumption.

A Computational Chemistry Approach for Investigation of Low Friction Mechanisms Based on FEP Film with Functionalized SiO2 Nanoparticles

2015 ◽  
Vol 1119 ◽  
pp. 142-150
Author(s):  
Yusuke Morita ◽  
Marleen de Weser ◽  
Gerhard Schottner
Keyword(s):  
Friction Coefficient ◽  
Internal Combustion Engines ◽  
Fuel Efficiency ◽  
Friction Reduction ◽  
Dynamics Simulation ◽  
Chemical Calculation ◽  
Combustion Engines ◽  
Low Friction ◽  
Reduction Mechanisms ◽  
Friction Measurements

To improve the fuel efficiency of automobile internal combustion engines, we investigated the fundamental mechanism of friction reduction within engine moving parts. A new coating was designed by introducing SiO2nanoparticles in FEP film. The SiO2nanoparticles were functionalized with hydrophobic fluoroalkyl units on their surface to create additional low friction property. Universal Surface Tester friction measurements revealed a significant reduction of the friction coefficient with increasing number of hydrophobic fluoroalkyl units for SiO2surface functionalization. To clarify the friction reduction mechanisms by the functionalization of SiO2nanoparticles, a quantum chemical calculation was carried out. The result indicates that an attractive force occurs between nanoparticle Si atoms and polymer F atoms, while by adding fluoroalkyl units on the SiO2nanoparticle surface, this force changes to repulsive. By performing a molecular dynamics simulation of a shear model between FEP film and SiO2nanoparticles, we observed a decrease of friction force with increasing fluoroalkyl units which lead smooth rolling motion of nanoparticles, thus confirming the repulsive effect of nanoparticle functionalization. We conclude that fluoroalkyl units on the SiO2surface play an important role in creating a repulsive force between nanoparticle and FEP film which lead to low friction coefficient.

Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn Four-Stroke Natural Gas Engine: Experimental Results

2007 ◽  
Vol 129 (4) ◽  
pp. 1088-1094
Author(s):  
Kris Quillen ◽  
Rudolf H. Stanglmaier ◽  
Luke Moughon ◽  
Rosalind Takata ◽  
Victor Wong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Piston Ring ◽  
Department Of Energy ◽  
Experimental Results ◽  
Friction Reduction ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Computational Tools ◽  
Ring Pack ◽  
Institute Of Technology

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT), and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the U.S. Department of Energy. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼0.50% improvement in mechanical efficiency (ηmech).

Influence of the Position of Oil Drain Holes of a Piston on Lubricating Oil Consumption

2017 ◽  
Author(s):  
Hiroki Hasegawa ◽  
Koji Kikuhara ◽  
Akemi Ito ◽  
Shunsuke Nishijima ◽  
Masatsugu Inui ◽  
...  
Keyword(s):  
Piston Ring ◽  
Gasoline Engine ◽  
Pressure Sensors ◽  
Lubricating Oil ◽  
Oil Consumption ◽  
Tracer Method ◽  
Low Friction ◽  
Piston Skirt ◽  
Generation Mechanisms ◽  
Good Agreement

An increase in lubricating oil consumption in an engine causes an increase in particulate matters in exhaust gases, poisoning the catalyst of after treatment devices, abnormal combustion in a turbo-changed gasoline engine and so on. Recent trend of low friction of a piston and piston ring tends to increase in lubricating oil consumption. Therefore reducing oil consumption is required strongly. It is known that oil pressure generated under the oil ring affects lubricating oil consumption. It is also known that the position of oil drain holes affects lubricating oil consumption. In this study, the effect of the position of oil drain holes on oil pressure under the oil ring and lubricating oil consumption was investigated. The oil pressure under the oil ring is measured using fiber optic pressure sensors and pressure generation mechanisms were investigated. Lubricating oil consumption was also measured using sulfur tracer method and the effects of oil drain holes against the oil pressure under the oil ring were evaluated. Four types of arrangement of oil drain holes were tested. The oil pressure variations under the oil ring in the circumferential direction was measured using a gasoline engine. An increase in oil pressure was found during down-stroke of the piston. The lowest oil pressure was found for the piston with four oil drain holes. Two holes nearby the front / rear end of the piston skirt showed relatively lower pressure. The measured results of oil consumption showed good agreement to measured oil pressure under the oil ring. It was found that oil pressure under the oil ring affected oil consumption, and oil drain holes set near the front / rear end of the piston skirt were effective for reducing oil consumption.

scholarly journals The Rotating Liner Engine (RLE) Diesel Prototype: Reducing Internal Engine Friction by about 40% under Idle Conditions

2021 ◽  
Vol 11 (2) ◽  
pp. 779
Author(s):  
Dimitrios Dardalis ◽  
Amiyo Basu ◽  
Matt J. Hall ◽  
Ronald D. Mattthews
Keyword(s):  
Internal Combustion Engines ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Friction Reduction ◽  
Contact Boundary ◽  
Metal Contact ◽  
Load Testing ◽  
Gas Leakage ◽  
Brake Mean Effective Pressure ◽  
Economy Benefit

The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2–4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential to eliminate the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 100 bar) and up to about 10 bar BMEP (brake mean effective pressure). Preliminary testing has proven that the metal-to-metal contact in the piston assembly mostly vanished, and a friction reduction at idle conditions of about 40% as extrapolated to a complete engine has taken place. It is expected that as the speed increases, the friction reduction percentage will diminish, but as the load increases, the friction reduction will increase. The fuel economy benefit over the US Heavy-Duty driving cycle will likely be of the order of 10% compared to a standard engine.

A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

2021 ◽  
pp. 146808742110050
Author(s):  
Enrica Malfi ◽  
Vincenzo De Bellis ◽  
Fabio Bozza ◽  
Alberto Cafari ◽  
Gennaro Caputo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Pollutant Emissions ◽  
Average Error ◽  
Combustion Engines ◽  
Nitric Oxides ◽  
Lean Burn ◽  
Fuel Charge ◽  
Unburned Hydrocarbons ◽  
Model Reliability

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

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