Ring Liner Research Articles

Simulation based analysis to study the effect of compression ring crown height in ring liner assembly on the performance of four stroke petrol engine

Among different piston rings of an Internal Combustion Engine (IC), the top compression ring-liner assembly shared a momentous amount of the total frictional losses, particularly at the Top Dead Center (TDC) and Bottom Dead Center (BDC) where boundary lubrication subsists. In the present study, the lubrication mechanism in piston ring cylinder liner conjunction for top compression ring using one dimensional Reynolds equation assuming axisymmetric contact was studied. The hydrodynamic and mixed lubrication regimes were taken during the study. Gumbel boundary conditions were used for Reynolds equation solution. For boundary pressure calculation, first, combustion chamber pressure variation was determined, then, interring pressure was calculated assuming orifice volume method by solving mass flow rate through crevice volumes using Runge-Kutta 4th order method. The Reynolds equation was solved using finite difference method. Whole solution process was repeated for different engine speed and crown height of top compression ring to study the effect of them in wear and power loss. First, the solution was found for 3000, 5000 and 7500 RPM keeping constant crown height of 10 µm. Average power loss was found to be increased with the increasing engine speed. There was increased in oil film thickness around mid-stroke with the increased engine speed, but there was no significant change in film thickness with the engine speed at the TDC and BDC positions. Then, the solution was again repeated for different RPM varying the crown height. The compression ring with lower crown height showed the better wear performance by increasing the minimum film thickness in critical zones of engine cycle for all RPM. The crown height of 5,7 and 9 µm gave the minimum power loss (77.89, 163.47 and 297.33 W) for 3000, 5000 and 7500 rpm. Moreover, the power loss in the range of 5-9 µm had no significant differences.

Thickness Measurement of Self-Lubricating Fabric Liner of Inner Ring of Sliding Bearings Using Spectral-Domain Optical Coherence Tomography

This study presents a novel and highly accurate method of measuring the geometric thickness of the self-lubricating fabric liner of bearings by combining the optical coherence tomography (OCT) technology and the Hanning-windowed energy centrobaric method (HnWECM). The geometric thickness of wear-resistant coating material is one of the important indicators for evaluating its wear, and the measurement of its geometric thickness is of great significance for preventing coating failure. To address the issue of significant measurement errors caused by using the refractive index of the sample instead of the group refractive index to calculate the material’s geometrical thickness in previous OCT research and applications, our proposed method can accurately measure the geometrical thickness of materials without the influence of the refractive index of the material. Moreover, this method exhibits the advantages of non-contact and high precision, since it utilizes an SD-OCT system, making it a novel method for extracting the physical parameters of composite materials. The geometric thickness of the peeled-off liner obtained from our method is compared with the thickness measured by the spiral micrometer to evaluate its accuracy. The experimental results indicate that the thickness measured by the spiral micrometer was 172 μm, while the maximum difference in the data obtained by our method was 171.261 μm. This suggests that the difference between the two methods is less than 0.430%, which verifies the accuracy and validity of our method. Additionally, the obtained geometric thickness and the optical thickness of the peeled-off liner are used to evaluate the group refractive index of this material. The inside geometrical structure of the self-lubricating fabric liner on the end face and inner ring of the sliding bearing is imaged with this group refractive index. The measurement of the inner ring liner of the sliding bearing proves the flexibility of the fiber-optic OCT and provides a non-contact, nondestructive testing method for measuring the geometric thickness and internal geometric structure of composite materials.

An Examination of Effect of Impact on Four Stroke 4 Cylinder Petrol Engine using Different Engine Oil

In the gas powered motor not practically everything moved to the cylinder from the gases contained inside the chamber the Demonstrated work is accessible at the drive shaft for real work.. The grinding delivered because of PRA(piston ring assembly) has a significant commitment altogether frictional misfortunes of the motor. The piston ring gathering is predominant wellsprings of the motor scouring force. This work endeavors to assess the frictional power at the piston ring liner gathering by utilizing different motor oil. To assess the frictional power a model ready by the YUKIO is thought of. The exploratory work was led on a four stroke 4-chamber SI motor from speed range from 1500 rpm to 3000 rpm. It is seen that the greatest worth of the frictional power is higher for the ointment SAE30W which might reason for higher wear of the rings. The utilization of grease SAE15W in the given arrangement would make less wear of piston rings due diminish frictional powers. Key words:- Piston Ring Assembly, Gas powered cycle, friction, wear, SAE.

Piston Compression Ring Elastodynamics and Ring–Liner Elastohydrodynamic Lubrication Correlation Analysis

Friction loss in an internal combustion engine largely depends on elastohydrodynamic lubrication. The piston compression ring is a contributor to such parasitic losses in the piston subsystem. The complex elastodynamics of the ring are responsible for the transient and regime-altering film that affects the elastohydrodynamic lubrication of the ring liner contact conjunction. The current paper will discuss the ring radial, lateral deformation, and axial twist, and its effect on the film profile of the compression ring and its subsequent effect on tribological characteristics like elastohydrodynamic pressure, friction, and lubricant. A finite difference technique is used to solve the elastohydrodynamic issue of elastodynamic piston compression by introducing the elastodynamically influenced film thickness into the lubrication model. The results show that consideration of the elastodynamics predicts a 23.53% reduction in friction power loss in the power stroke due to the elastodynamic ring compared to the rigid ring. The elastodynamic effect improves the lubricant oil flow into the conjunction. A finite element simulation predicts a von-Mises stress of 0.414 N/mm2, and a maximum deformation of 0.513 µm at the core and coating interface is observed at the ring–ring groove contact. The sustainability of EHL in this case largely depends on the ring–liner elastodynamics.

Investigation of friction properties in the piston-cylinder liner region of a single-cylinder compressed air engine using the GT-SUITE program

Dependence on nonrenewable fuels continues to a great extent today. Overuse of fossil fuels has brought along various environmental problems. In order to reduce such problems, compressed air engines have developed significantly during the last 20 years. Compressed air engines are environment-friendly engines that do not use fossil fuel and achieve expansion using compressed air. It is of great importance for engine efficiency to decrease friction losses of piston engines. There are not many studies in the literature focusing on friction manner of piston ring liner parts of compressed air engines with a piston. In this article, the transformation of a four-stroke gasoline engine with 388 cm3 displacement into a compressed air engine has been carried out and the friction manner between piston cylinder liner has been modeled with the help of GT-SUITE program using in-cylinder pressure-cylinder volume (P-V) data obtained from different engine loads under operating pressure of 12 bar and geometrical size of the engine. It has been determined according to the results of the simulation that asperity friction losses have not changed significantly in top dead center and bottom dead center regions due to low testing speed, and hydrodynamic power losses have occurred in the middle of the course. Lack of combustion reactions in such engines has resulted in compression leakages and unavailability of a quality oil film layer. Since there are no combustion reactions, the eccentric movement of the pistons of the compressed air engines is changed by the lubricating oil, engine speed, compression leaks, and viscosity parameters.

Numerical investigation of radial thrust fluctuation caused by diffuser rotating stall in a centrifugal pump

Abstract In this study, in order to understand the relation between the diffuser rotating stall and the fluctuating radial thrust, unsteady RANS simulation of a centrifugal pump was carried out. The rotating stall with single stall cell was qualitatively reproduced though the propagation speed was smaller than the experiment. The pressure amplitude caused by the rotating stall was comparable to the measured one, and the tendency that the propagation speed increases as the flow rate increases agreed with experiment. The radial thrust fluctuation due to the rotating stall was well evaluated by the simulation, and a considerable difference of phase angle between the stall cell position and the working direction of radial thrust was detected, which also agreed with experiment. On the basis of simulation result, the reason is found to be that the radial force acting on the impeller external wall at the liner ring section due to stall cell was not very small but comparable to that acting on the impeller blade and outer wall, while their working directions were roughly 100° different. This suggests that considering the leakage flow in numerical simulation is important to accurately predict the radial forces generated by rotating stall.

Comparison of Marginal Fit of Metal Copings in Two Different States with and without Using Ring Liners: An In Vitro Study

To compare the marginal fit of Ni-Cr copings made by casting in two different states (dry and wet) with either cellulose ring liners or no ring liners. An in vitro study was conducted on 40 patterns which were invested, and a burnout casting procedure was used, using a Ni-Cr alloy to obtain the cast copings. The cast copings were divested, cleaned, and run through a finishing procedure. The copings were seated on the stainless steel die and microscopically evaluated for marginal discrepancies at two predetermined reference points using an optical microscope (Rieichert, Austria). Statistical analysis was done using Pearson's correlation coefficient and Chi-square test, keeping 95% confidence intervals and having a p value of less than 0.05 statistically significant. Our results identified marginal discrepancies in all the Ni-Cr cast copings, which significantly differed from each other. The copings obtained from casting with a cellulose ring liner in a wet state showed a significantly higher value followed by casting using a cellulose ring liner in a dry state. The mean marginal discrepancy values were within the clinically acceptable range for all the Ni-Cr cast copings included in two groups. Our study concludes that the copings cast with a cellulose ring liner in dry states had the least amount of vertical marginal discrepancies as compared to those that were cast with a ring liner in two different forms or those cast without a ring liner, suggesting that the use of cellulose ring liner in a dry state is favorable for all casting procedures. Measuring gaps or discrepancies at margins is the commonly used method to determine the fit of Ni-Cr copings. In order to minimize marginal inaccuracies, various authors have suggested different methods to improve the marginal adaptation of cast restorations. There are compensation methods like setting expansion, hygroscopic expansion, and thermal expansion of the investment, which are used to assess metal shrinkage during cooling.

Tribological evaluation of piston ring/cylinder liner assembly in automotive engines using GNP as a lubricant additive

Friction and wear are the main causes of energy dissipation in automotive engines. To minimize the frictional power losses, it is extremely important to improve the tribological characteristics of ring/liner assembly which accounts for almost 40–50% frictional power losses. The present study attempts to mitigate friction and wear of the ring/liner tribo-pair using GNP/SAE 15W40 nano-lubricant. To simulate the ring/liner interface, the tribological performance of nano-lubricants was assessed using a tribometer based on ASTMG181 standard under various operating conditions. The coefficient of friction (COF) and wear rate lowered using graphene nano-lubricants (GNL). The tribological results showed that friction coefficient, wear rate, and surface roughness of piston ring improved in the range 17.71%–42.33%, 25%–40.62%, and 61%, respectively, under GNL lubricating conditions during the boundary lubrication. Further, the characterization of wear tracks of piston ring and cylinder liner confirmed tribo-film formation on worn surfaces resulting in decreased COF and wear rate.

Exploring the lubrication mechanism of CeO2 nanoparticles dispersed in engine oil by bis(2-ethylhexyl) phosphate as a novel antiwear additive

Energy-efficient engine oils are required for sustainable transportation using vehicles, and oil companies aim to manufacture lube oils with more effective additives. Here we investigate the lubrication mechanism of cerium oxide (CeO2) nanoparticles dispersed in a fully synthetic engine oil (5 W-30) by bis(2-ethylhexyl) phosphate (HDEHP). Tribological tests were conducted using a tribometer based on ASTMG181 to mimic the ring–liner tribosystem environment. The results showed that the CeO2 nanolubricant enhanced the antifriction and antiwear characteristics of the rubbing surfaces by 12–21% and 62–80%, respectively, contrary to the results obtained with the 5 W-30 oil. In-depth field emission scanning electron microscope, energy dispersive spectrometer, and X-ray photoelectron spectrometry analyses of the worn surfaces after lubrication evidenced the production of a tribofilm, induced by physical adsorption and tribochemical reactions. Concisely, this study demonstrates the superior tribological performance of the CeO2 nanolubricant and provides insights for developing lube oils and improving the fuel economy in vehicle engines.

Friction at Ring–Liner Interface Analyzed with a Systematic Surface Characterization

The ring–liner interface of an internal combustion engine is a very important interface because its behavior directly affects fuel efficiency of an automobile and the engine life. The liner surface is complicated, with honing features on top of the primary roughness. Moreover, liner surfaces considered here also contain pores that are random in terms of their shape and distribution. The work reported in this article systematically models the tribological performance of such surfaces in a ring–liner interface. A microscopic single-pore computational fluid dynamics analysis is conducted on the representative pore shape obtained from liner–surface characterization to quantify the effect of pores on friction. A pore influence zone is suggested, and a friction reduction factor is defined for pores. A macroscopic ring–liner interface model is developed in parallel to solve the average Reynolds equation for a representative section with the consideration of the starvation and cavitation effects. The two models are then combined to predict friction at the ring–liner interface for the liner surfaces with pores. Excellent agreement is observed between our modeling and experimental results. The effects of random pores of varying densities in the range of 2–10% on the ring–liner interface performance are studied under flooded and starved conditions. The results indicate that surface pores increase friction when the ring–liner set is operated under flooded conditions. However, when starvation occurs, surface pores help reduce friction.

Shear-area variation: A mechanism that reduces hydrodynamic friction in macro-textured piston ring liner contacts

Using a reciprocating rig to simulate the piston ring-cylinder liner contact, we show that macro-scale surface texture yields friction reductions in the hydrodynamic regime of up to 35%. Based on these experimental observations, we put forward a new macro-texture induced friction reduction mechanism and validate it through theoretical 1D modelling. This “Shear-Area Variation” mechanism involves macro-texture reducing both the sheared contact area (acting to decrease friction) and hydrodynamic load support/lubricant film thickness (acting to increase shear-rate and hence friction). Provided the oil film is thick enough to prevent asperity contact, the area reduction effect dominates the friction response. This has implications for machine efficiency improvements, as friction is reduced around mid-stroke where sliding speed and energy dissipation is greatest. It also complements the majority of surface texture research which involves micro-scale texture that is only effective at low speeds in the mixed and boundary regimes (around top and bottom- dead centre).

The Investigation into the Tribological Impact of Alternative Fuels on Engines Based on Acoustic Emission

The wide use of different alternative fuels (AL) has led to challenges to the internal combustion (IC) engine tribology. To avoid any unpredicted damages to lubrication joints by using AL fuels, this study aims to accurately evaluate the influences of alternative fuels on the tribological behavior of IC engines. Recent achievements of the acoustic emission (AE) mechanism in sliding friction provide an opportunity to explain the tribological AE responses on engines. The asperity–asperity–collision (AAC) and fluid–asperity–shearing (FAS) mechanisms were applied to explain the AE responses from the piston ring and cylinder liner system. A new adaptive threshold–wavelet packets transform (WPT) method was developed to extract tribological AE features. Experimental tests were conducted by fueling three fuels: pure diesel (PD), biodiesel (BD), and Fischer–Tropsch (F–T) diesel. The FAS–AE indicators of biodiesel and F–T diesel show a tiny difference compared to the baseline diesel using two types of lubricants. Biodiesel produces more AAC impacts with higher AAC–AE responses than F–T diesel, which occurs at high speeds due to high temperatures and more particles after combustion than diesel. This new algorithm demonstrated the high performance of using AE signals in monitoring the tribological impacts of alternative fuels on engines.

Potential of CuS and CuO nanoparticles for friction reduction in piston ring–liner contact

ABSTRACT An experimental study on the use of Cu nanofluids as engine oils for reduction of friction in piston ring–liner contact is presented. The Cu nanofluids were prepared using CuS and CuO nanoparticles and blending them in 0.1–6% concentration by weight in the commercial engine oils. The Cu nanoparticles were synthesised and characterised after mixing with the lubricant for their physico-chemical characteristics. The experiments were performed on a reciprocating tribo-tester using actual piston rings and the liners as test specimens. Experiments were performed to investigate the effect of nanoparticle concentration with the change of contact loads and reciprocating frequency on the coefficient of friction. The study reveals that the Cu nanoparticles blended in the engine lubricating oils can significantly reduce friction between piston ring–liner contact, desirable for fuel economy improvement. The Cu nanoparticles are compatible with base lubricants and result in significant friction reduction. The CuS nanoparticles performed significantly better than the CuO nanoparticles.

Field-Testing of Biodiesel (B100) and Diesel-Fueled Vehicles: Part 4—Piston Rating, and Fuel Injection Equipment Issues

AbstractThis study investigated the use of biodiesel (B100) and baseline diesel in two identical unmodified vehicles to realistically assess different aspects of biodiesel's compatibility with modern common rail direct injection (CRDI) fuel injection equipment (FIE) and evaluate biodiesel's long-term durability/compatibility with engine components. Two identical vehicles were fueled with biodiesel (B100) and baseline mineral diesel for 30,000 km field-trials on highway under identical operating conditions. Exhaustive experimental results from this series of tests are divided into four segments. The fourth and the last paper of this series compares the effects of long-term usage of biodiesel on piston deposits and FIE components compared to baseline mineral diesel. A key challenge for improving engine performance and fuel economy is the reduction of frictional losses, primarily at the piston ring–liner interface, which accounts for majority of frictional losses. Piston rating was done for the two vehicles after the conclusion of field-trials and it revealed that rating of different piston sections was ∼5–15% superior in case of biodiesel-fueled vehicle compared to that of diesel-fueled vehicle. Performance of FIE components such as fuel filter, fuel injectors, and fuel pump was assessed after the conclusion of field-trials. Pressure drop at different fuel flow-rates across the fuel filter was measured for assessing the fuel filter blockage. Pressure drop across biodiesel filter was ∼30% higher than diesel filter after 10,000 km usage but almost twice after 15,000 km usage. These experimental results indicated that some additional technical measures should be taken by automotive manufacturers to offset these technical challenges before biodiesel is adapted on a large-scale in modern CRDI vehicles.

The compression ring profile influence on hydrodynamic performance of the lubricant in diesel engine

For different operating conditions of an internal combustion engine, the piston–ring–liner compartment represents one of the largest sources of friction and power losses. The aim of this article is to evaluate the effect of the compression ring profile on the main tribological performance of the lubricant in a four-stroke diesel engine. A one-dimensional analysis was developed for the hydrodynamic lubrication between the compression piston ring and the cylinder wall. A numerical method was applied to analyze the influence of different ring geometrical designs during the working cycle on oil film thickness, frictional force, and power losses. Our predicted results were validated with the Takiguchi data of a previous study, and they have shown a good agreement. The results in the current analysis demonstrated that the ring geometry profile, the engine speed, and load have a remarkable effect on oil film thickness, friction force, and friction power losses between the top ring and cylinder liner. Therefore, it would help in reducing friction as well as making a contribution to the improvement of engine performance such as torque, efficiency, and fuel consumption.

Experimental Wear Study between Piston Ring and Cylinder Liner Pair with Mahua Oil as Lubricant for Automobiles

This paper developed a wear testing machine and investigated experimental study of wear among cylinder liner (CL) and piston ring (PR) pair for automobiles. Mahua oil is used as the lubricant between the CL and PR pair. The process parameters are controlled to reduce the weight loss of PR using response surface methodology (RSM). The three process parameters such as applied load, sliding velocity and quantity of oil are considered. It is observed that sliding velocity and applied load are the most influencing parameters whereas the interaction of quantity of oil has less influencing parameter on weight loss of PR. Experimental results are in good compatibility with the values from the theoretical model.

Thermal Modeling of Thin Lubricant Film Within Piston Compression Ring and Rough Cyliner Liner Conjuction

This work is devoted to develop a transient thermo elastohydrodynamic model for thermal analysis of micro scale oil film with in piston compression ring-liner conjunction. In this paper, heat dissipation through piston to cylinder wall mainly considered via thin film of lubricant on convection and conduction mode. It also includes frictional heat generated due to ring liner co-action while balancing total heat of the engine system. Results presented in this paper show that frictional heating raises additional lubricant temperature of 900 C. Such increase in temperature is one of the reasons for presence of further oil degradation in high pressure zone of engine cycle, which appears between 3000 to 4000 crank location.

Contact modeling with a finite element model in piston ring‒liner conjunction under dry conditions

PurposeThe purpose of this paper is to focus on the creation of an isothermal elastic ring-liner model to highlight, through stresses, the occurrence of the plastic deformation in certain crank angles under extreme dry lubrication conditions.Design/methodology/approachThe stresses that are exported from this analysis are pointing out not only the necessity for an elastoplastic model to be created, but also the importance of predicting the correct friction coefficient, as pointed out by both the contact surface stress and that in depth of the two bodies in contact.FindingsThe comparison between the finite element model and the adhesion mathematical model of Johnson, Kendall and Roberts seals the importance to calculate the interaction forces, acting on the common solid surface, in the pursuit of defining a propriate contact patch. Additionally, a three-dimensional ring model is built, highlighting the importance of the modeling surface’s micro asperities for a solid stress analysis. Also, numerical experiments are conducted, in contact with the cylinder and a piston ring made of an iron alloy and of two different plating materials, such us Chromium (Cr) and Chromium‒Nickel Alloy (CrN). The ability to calculate the stress concentration factor is also described.Originality/valueA three-dimensional ring model is built, highlighting the importance of the modeling surface’s micro asperities for a solid stress analysis. Also, numerical experiments are conducted, in contact with the cylinder and a piston ring made of an iron alloy and of two different plating materials, such us Chromium (Cr) and Chromium‒Nickel Alloy (CrN). The ability to calculate the stress concentration factor is also described.

EXPERIMENTAL INVESTIGATION TO ENHANCE THE TRIBOLOGICAL CHARACTERISTICS OF A LUBRICANT USING NANOPARTICLE ADDITIVE

Copper oxide (CuO) nanoparticles were found to be an excellent additive to the lubricant in order to reduce the friction and wear between piston ring and cylinder liner. Friction and wear tests have been done experimentally using a pin on disc machine. Input parameters like load, speed, distance travelled are varied for each test, so that an effective combination for the minimal friction and wear have been obtained. The effect of adding additive is also found by varying the percentage of the nanoparticle in the lubricant. Also, after the best ratio for the additive in lubricant is selected, it can be used to run the engine in the laboratory, so that the performance and emissions of the engine with the new lubricant can be obtained. Finally, comparison can be made with the engine using existing lubricant.

An Investigation into the Acoustic Emissions of Internal Combustion Engines with Modelling and Wavelet Package Analysis for Monitoring Lubrication Conditions

Online monitoring of the lubrication and friction conditions in internal combustion engines can provide valuable information and thereby enables optimal maintenance actions to be undertaken to ensure safe and efficient operations. Acoustic emission (AE) has attracted significant attention in condition monitoring due to its high sensitivity to light defects on sliding surfaces. However, limited understanding of the AE mechanisms in fluid-lubricated conjunctions, such as piston rings and cylinder liners, confines the development of AE-based lubrication monitoring techniques. Therefore, this study focuses on developing new AE models and effective AE signal process methods in order to achieve accurate online lubrication monitoring. Based on the existing AE model for asperity–asperity collision (AAC), a new model for fluid–asperity shearing (FAS)-induced AE is proposed that will explain AE responses from the tribological conjunction of the piston ring and cylinder. These two AE models can then jointly demonstrate AE responses from the lubrication conjunction of engine ring–liner. In particular, FAS allows the observable AE responses in the middle of engine strokes to be characterised in association with engine speeds and lubricant viscosity. However, these AE components are relatively weak and noisy compared to others, with movements such as valve taring, fuel injection and combustions. To accurately extract these weaker AE’s for lubricant monitoring, an optimised wavelet packet transform (WPT) analysis is applied to the raw AE data from a running engine. This results in four distinctive narrow band indicators to describe the AE amplitude in the middle of an engine power stroke. Experimental evaluation shows the linear increasing trend of AE indicator with engine speeds allows a full separation of two baseline engine lubricants (CD-10W30 and CD-15W40), previously unused over a wide range of speeds. Moreover, the used oil can also be diagnosed by using the nonlinear and unstable behaviours of the indicator at various speeds. This model has demonstrated the high performance of using AE signals processed with the optimised WPT spectrum in monitoring the lubrication conditions between the ring and liner in IC engines.