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.

scholarly journals Enhancing the Geometrical Performance Using Initially Conical Cylinder Liner in Internal Combustion Engines—A Numerical Study

2020 ◽  
Vol 10 (11) ◽  
pp. 3705
Author(s):  
Ahmad Alshwawra ◽  
Florian Pohlmann-Tasche ◽  
Frederik Stelljes ◽  
Friedrich Dinkelacker
Keyword(s):  
Internal Combustion Engines ◽  
Thermal Stresses ◽  
Numerical Study ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Friction Reduction ◽  
Cylindrical Shape ◽  
Combustion Engines ◽  
Cold State ◽  
The Impact

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.

scholarly journals Numerical study of the physical processes of gas leakage in the compression ring in diesel engines

2021 ◽  
Vol 2118 (1) ◽  
pp. 012016
Author(s):  
J A Pabón León ◽  
J P Rojas Suárez ◽  
M S Orjuela Abril
Keyword(s):  
Numerical Model ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Cylinder Liner ◽  
Combustion Engines ◽  
Combustion Gases ◽  
Gas Leakage ◽  
Lubrication Film ◽  
Compression Ring ◽  
Complex Mathematical Model

Abstract In this research, the construction of a numerical model is proposed for the analysis of the friction processes and the thickness of the lubrication film present in the compression ring of internal combustion engines. The model is built using MATLAB software, and three load conditions are used as reference (2 Nm, 4 Nm, and 6 Nm) with a rotation speed of 3600 rpm, which correspond to a stationary single-cylinder diesel engine. Comparison between model estimates and experimental results show that the development model could predict the actual engine conditions. The deviation between the numerical model and the experimental data was 17%. It was shown that the increase in engine load causes a 16% increase in the friction force of the compression ring, which implies a 50% increase in power loss due to friction processes. In general, the model developed allows the analysis of the friction processes in the compression ring and its effect on the lubrication film, considering the leakage of the combustion gases. In this way, the construction of a more complex mathematical model is achieved, which allows improving the precision in the analyzes related to the interaction between the compression ring and the cylinder liner.

Modeling of Axial and Circumferential Ring Pack Lubrication

2001 ◽  
Author(s):  
Mikhail A. Ejakov
Keyword(s):  
Hydrodynamic Lubrication ◽  
Three Dimensional ◽  
Cylinder Liner ◽  
Mixed Lubrication ◽  
Contact Boundary ◽  
Asperity Contact ◽  
Oil Viscosity ◽  
Friction Forces ◽  
Crank Angle ◽  
Ring Pack

Abstract The ring-pack lubrication is a complicated physical process involving multiple physical phenomena. This paper presents an attempt to model the ring-pack lubrication in three-dimensional space, considering the ring-bore structure interaction, bore distortion, ring-twist, piston secondary motion, non-Newtonian lubricant behavior, and ring/bore asperity contacts. The physics of the model includes the interface between the structure of the ring, oil lubricant, and the structure of the cylinder liner. The ring is modeled as a three-dimensional FEA model with the nodes along the ring circumference. The ring face orientation changes circumferentially depending on ring geometry as well as piston tilt angle and three-dimensional ring twist angle at every crank angle degree. The oil lubrication is modeled with the Reynolds equation with shear thinning and temperature dependent oil viscosity and with or without the flow factors. The cylinder liner description allows three-dimensional bore distortion and ring/liner asperity contact to be modelled. The key of the analysis is solving simultaneously at every crank angle increment a set of coupled linear and non-linear equations of ring structure, ring face lubrication, bore distortion, and asperity contact. The model predicts variations of the ring-pack lubrication in the axial and circumferential directions. Using the hydrodynamic lubrication model coupled with the asperity contact model allows calculations of the friction forces due to asperity contact (boundary and mixed lubrication) and oil film interactions (hydrodynamic and mixed lubrication). The transition from hydrodynamic lubrication to boundary lubrication through mixed lubrication is determined interactively based on ring / liner surface properties, ring loads, and lubrication properties. The new friction sub-module calculates axial and circumferential variation of both types of friction forces as well as total friction. The asperity contact induced friction forces and asperity contact pressure can further be used for ring wear calculations. The developed model has been applied to determine the performance of a production engine ring-pack. The influence of different phenomena affecting the ring-pack performance has been analyzed and compared.

Experimental Investigation of Surface Modifications for Piston-Ring/Cylinder-Liner Friction Reduction

2008 ◽  
Author(s):  
Marko S. Cater ◽  
Nathan W. Bolander ◽  
Farshid Sadeghi
Keyword(s):  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Surface Modifications ◽  
Friction Reduction ◽  
Analytical Models ◽  
Reciprocating Motion ◽  
Lubrication Regime ◽  
Average Coefficient ◽  
Lubrication Condition ◽  
Micro Dimples

Micro-dimples on the surface of lubricated sliding contacts can act as mini-hydrodynamic bearings. The pressure generated within these dimples tends to separate the surfaces and reduce the number of asperities in contact, thereby lowering the average coefficient of friction and moving the lubrication condition to the more stable hydrodynamic lubrication regime. An experimental study on the effects of laser surface modifications for friction reduction is presented through the use of several experimental test rigs. Micro-dimples were generated with an Nd-YAG laser on the surface of flat samples for testing in constant speed and reciprocating motion test rigs. These simple geometries were used to investigate the phenomenon and validate existing analytical models. Modifications to the top dead center region of an actual cylinder liner were evaluated with a motored, small-engine dynamometer. The results demonstrated that measurable friction reductions can be achieved using this approach.

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.

Mutual influence of plateau roughness and groove texture of honed surface on frictional performance of piston ring–liner system

2016 ◽  
Vol 231 (7) ◽  
pp. 838-859 ◽  
Author(s):  
Yang Hu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Jiazheng Fan
Keyword(s):  
Piston Ring ◽  
Cylinder Liner ◽  
Texture Features ◽  
Groove Depth ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Lubrication Performance ◽  
Liner System ◽  
Frictional Performance

The cylinder liner surface finish, which is commonly produced using the honing technique, is an essential factor of engine performance. The characteristics of the texture features, including the cross-hatch angle, the plateau roughness and the groove depth, significantly affect the performance of the ring pack–cylinder liner system. However, due to the influence of the honed texture features, the surface roughness of the liner is not subject to Gaussian distribution. To simulate the mixed lubrication performance of the ring–liner system with non-Gaussian roughness, the combination of a two-scale homogenization technique and a deterministic asperities contact method is adopted. In this study, a one-dimensional homogenized mixed lubrication model is established to study the influence of groove parameters on the load-carrying capacity and the frictional performance of the piston ring–liner system. The ring profile, plateau roughness, and operating conditions are taken into consideration. The main findings are that for nonflat ring, shallow and wide groove textures are beneficial for friction reduction, and there exists an optimum groove density that makes the friction minimum; for flat ring, wide and sparse grooves help improving the tribological performance, and there exists an optimum groove depth that makes the friction minimum.

scholarly journals A Study of Parameters Affecting Wear Resistance of Alumina and Yttria Stabilized Zirconia Composite Coatings on Al-6061 Substrate

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
N. Krishnamurthy ◽  
M. S. Prashanthareddy ◽  
H. P. Raju ◽  
H. S. Manohar
Keyword(s):  
Internal Combustion Engines ◽  
Composite Coatings ◽  
Wear Test ◽  
Cylinder Liner ◽  
Yttria Stabilized Zirconia ◽  
Atmospheric Plasma ◽  
Equal Proportion ◽  
Stabilized Zirconia ◽  
Bond Coats ◽  
Al 6061

In this investigation, a composite coating of alumina and yttria stabilized zirconia in equal proportion was developed on Al-6061 substrate using Atmospheric Plasma Spraying technique. Two commercially available powders of chemical composition Al 25Fe7Cr5Ni and Al2O330(Ni 20Al) were used as bond coats. The coating samples were subjected to abrasive wear test as per ASTM G99. From the results it was found that wear rate and coefficient of friction depend on various parameters such as microstructure, surface roughness, porosity, coating thickness, and hardness. It was also found that the mechanism of wear is mainly due to abrasion and once the bond coat is exposed to the disc, it loses material by adhesion. As the coating systems possess α-Al2O3 and ZrO2, they can be used for wear and heat resistant applications such as cylinder liner of internal combustion engines.

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