Characterization of various coatings in terms of friction and wear for internal combustion engine piston rings (original) (raw)
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Types of Piston Ring Coating Techniques- A Review
Journal of emerging technologies and innovative research, 2018
In the current scenario, there is a global drive for light as well as heavy duty vehicles to meet the legal norms of vehicle emissions. The surface engineering approach has emerged to be the possible solutionwhich is attracting increasing attention worldwide. Through this approach certain light weight alloys such as Mo, CrC are employed to utilise the best of their properties towards fuel and energy saving thereby enhancing the overall engine life. This review paper caters to give an idea of broad category of different coating techniques that are currently being adopted by industries in the application of piston ring coating in order to increase engine efficiency and life. The paper also highlights the effect of different coating technique on the tribological behaviour of the piston ring such as wear resistance, surface morphology, surface hardness, adhesion, coefficient of friction etc. Apart from that, this paper also demonstrates the relative significance of coating techniques in...
An Experimental Investigation of Piston Coating on Internal Combustion Engine
The thermal efficiency of most commercially used engine ranges from 38% to 42%, as nearly 58% to 62% of energy is lost in the form of waste heat. In order to save energy the hot parts are insulated. This will lead to reduction in heat transfer through the engine, involving an increased efficiency. Change in combustion process due to insulation also affects emissions. In this study an attempt is made to reduce the intensity of thermal and structural stresses by using a layer of ceramic material. Experimental investigation is carried out under different loading conditions on single cylinder two stroke spark ignition engine with its piston crown coated with Nickel-Chromium & Al2O3 to understand the influence of thermal barrier coating (TBC) on performance characteristics. Al2O3 is chosen as a candidate material for coating the piston crown because of its desirable physical properties like low thermal conductivity, high coefficient of thermal expansion, high thermal resistance, chemical inertness, high resistance to erosion, corrosion and high strength. Thermal barrier coating (TBC) is done by using Plasma Spraying Technique. Engine working conditions are maintained constant before and after coating. Experimental results revealed that the thermal efficiency is increased by 13.75%, Mass of fuel consumption is reduced by 6.02% and brake specific fuel consumption is reduced by 9.84% between coated and bare engine.
Wear, 2011
The piston system accounts for roughly half of the mechanical friction of an internal combustion engine, thus it is important to optimize. Different thermally sprayed cylinder liners were investigated in order to optimize the frictional impact of the contact between cylinder liner and piston ring/piston. A novel tribometer test setup was used to scan through different materials at different running conditions. Two cylinder liner materials showed significantly lower friction than the other tested materials, CrC-NiCr and MMC. All the thermally sprayed cylinder liners were worn significantly less than the reference material. Based on these results a full-scale single cylinder test was performed to validate the results from the rig. Comparing the thermally sprayed cylinder liner MMC with reference cylinder liner the test showed higher friction torque for the MMC cylinder liner except in one case; at low speed and high pressure. An analysis of the results between the tribometer and the engine points at the importance of the ratio between viscous and mechanical friction losses. The most probable cause of higher friction torque for the thermally sprayed coating (MMC) is that the functional surface of the cylinder liner promotes an increase in viscous friction.
Experimental friction evaluation of cylinder liner/piston ring contact
Wear, 2011
Fuel consumption is an extremely important parameter for the automotive industry today. Anticipated emission legislative demands in combination with a rising oil price are true motivators. In engines the piston system is the largest source of frictional losses, accounting for about 50% of the total frictional losses, thus it is important to optimize. Apart from frictional losses the piston system is a large consumer of lubricating oil, a considerable contributor to the total amount of particulate emissions (PM). New materials, coatings and high-tech machining processes that previously were considered to be too expensive and therefore only used in complex applications are today becoming more affordable. It is important to develop reliable test methods to study these new concepts. The reciprocating tribometer at Volvo Technology has been updated to better evaluate the frictional difference between material combinations/surfaces; it is possible to evaluate a number of operational parameters in each experiment. The components that were studied were a piston ring running against a cylinder liner. Friction, wear and change in surface morphology were studied in the experiments. It is shown that for the introduced DoE based tribometer test the interaction of dynamic viscosity, velocity and contact pressure can be studied within one experiment. The results show differences in friction which could be explained as the surface creating beneficial contact conditions for oil film build-up. It is also apparent that surface roughness is important regardless of material properties. To better understand the correlations between friction and surface roughness a future study should include a study of similar materials with different roughness values.
Applied Energy, 2020
IC engines contribute to global warming through extensive use of fossil fuel energy and emission of combustion by-products. Innovative technologies such as cylinder de-activation (CDA), after-exhaust heat treatment, surface texturing and coatings are proposed to improve fuel economy and reduce emissions of the vehicle fleet. Therefore, study of coating technology through a comprehensive multi-physics analytical model of engine top compression ring is important to ascertain ways of promoting energy savings. This paper presents a multi-scale, multi-physics model of the compression ring-cylinder bore conjunction, using three alternative bore surfaces. The model comprises ring dynamics, contact tribology, heat transfer and gas blow-by. Tribological and thermal properties of advanced coatings, such as Nickel Nanocomposite (NNC) and diamond-like carbon (DLC) are compared with an uncoated steel bore surface as the base line configuration. Such a comprehensive analysis has not hitherto been reported in open literature, particularly with original contributions made through inclusion of salient properties of alternative bore materials for high performance race engines. Power loss and FMEP are evaluated in a dynamometric test, representative of the Worldwide harmonised Light vehicles Test Cycle (WLTC). The NNC coating shows promising tribological improvements. The DLC coating is detrimental in terms of frictional power loss and FMEP, although it can effectively improve sealing of the combustion chamber. The differences in power loss of nominated bore surfaces are represented as fuel mass and CO emissions, using theoretical and empirical relations. For the first time the paper shows that advanced coatings can potentially mitigate the adverse environmental impacts of spark ignition (SI) engines, with significant repercussions when applied to the global gasoline-powered vehicle fleet.
2012
This paper deals with testing of hard chromium coatings, which are used for piston rings. There were tested the standard hard chromium, porous chromium and composite chromium coatings. Wear resistance was tested by pin-on-disc method and by engine test. Coatings for pin-on-disc test were deposited on a steel plate. Al2O3 and WC balls were used as a counter part. Engine test of coatings was performed on a diesel passenger car engine. Coating used for engine test were applied to piston rings made of ductile cast iron. The engine was tested on a engine test bench. The evaluation was performed by optical microscope. Loss of material on the piston rings was measured by micrometer. The standard hard chromium coating showed the highest wear so results were related to this coating. The rate of wear depends on the type of counter part. Results of individual test methods are not sometimes comparable.
The Effects of Different Fuels on Wear between Piston Ring and Cylinder
Advances in Mechanical Engineering, 2014
In internal combustion engines, mechanical friction occurs between engine components in contact with each other, leading to wear and important loss of efficiency. Mechanical energy absorbed by piston ring-cylinder pair in piston engines accounts for the largest portion of efficiency losses due to mechanical friction. Different engine lubrication regimes significantly affect wear and friction. In addition to selection of compatible materials, improvement of operational conditions and the properties of lubricants and fuels are of great importance to minimize wear. This study investigated the effects of oil, diesel fuel, oil + diesel fuel, and two different biodiesel fuels (SOME: sunflower oil methyl ester and TSOME: tobacco seed oil methyl ester) as engine lubricants and their effects on wear in piston ring-cylinder pair. The tests were carried out at different engine speeds and loads. Minimum wear occurred when using engine oil as lubricant, and maximum wear occurred when using diese...
A Review of Wear in Piston Ring of Internal Combustion Engine
International Journal of Engineering Research and, 2015
The role of piston ring is to maintain an effective gas seal to transfer the heat from piston into cylinder wall and to limit the amount of oil from crankcase to the combustion chamber. The wear between piston ring and cylinder liner affects on the efficiency of the engine. The goal of this study was to study the effect of different parameters related to wear in piston ring.
This paper presents a model to study the effect of piston ring dynamics on basic tribological parameters that affect the performance of internal combustion engines by using dynamics analysis software (AVL Excite Designer). The paramount tribological parameters include friction force , frictional power losses, and oil film thickness of piston ring assembly. The piston and rings assembly is one of the highest mechanically loaded components in engines. Relevant literature reports that the piston ring assembly accounts for 40% to 50% of the frictional losses, making it imperative for the piston ring dynamics to be understood thoroughly. This analytical study of the piston ring dynamics describes the significant correlation between the tribological parameters of piston and rings assembly and the performance of engines. The model was able to predict the effects of engine speed and oil viscosity on asperity and hydrodynamic friction forces, power losses, oil film thickness and lube oil consumption. This model of mixed film lubrication of piston rings is based on the hydrodynamic action described by Reynolds equation and dr y contact action as described by the Greenwood–Tripp rough surface asperity contact model. The results in the current analysis demonstrated that engine speed and oil viscosity had a remarkable effect on oil film thickness and hydrodynamic friction between the rings and cylinder liner. Hence , the mixed lubrication model, which unifies the lubricant flow under different ring–liner gaps, is needed via the balance between the hydrodynamic and boundar y lubrication modes to obtain minimum friction between rings and liner and to ultimately help in improving the performance of engines. Keywords Internal combustion engines, piston ring dynamics, boundar y lubrication friction, hydrodynamic friction, lube oil consumption