Статті в журналах: "Piston ring assembly"

1

NAKASHIMA, Kohei, and Yosuke UCHIYAMA. "Experimental development of apparatus to measure piston assembly friction in an eco-mileage vehicle engine." Combustion Engines 177, no. 2 (May 1, 2019): 55–59. http://dx.doi.org/10.19206/ce-2019-210.

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Apparatus was developed to measure piston assembly friction with a floating cylinder liner against crank angle, using components of an eco-mileage vehicle engine as much as possible. This apparatus was then used to investigate the effect of different sets of piston rings on piston assembly friction in an eco-mileage vehicle engine. Results indicated that, compared to the piston with all three rings (a top ring, a second ring and an oil ring), the piston with two rings (a top ring and an oil ring) reduced piston assembly friction at all engine temperatures and engine speeds. Another configuration of two rings, with the top ring and the second ring, but without the oil ring, reduced friction at a lower engine temperature and speed, but was almost the same as the three-ring set at a higher engine temperature and speed. Finally, a one-ring set, with only the top ring, further reduced friction, except at a higher temperature and speed, where friction was greater than the two-ring set without the second ring.

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2

Ahmed Ali, Mohamed Kamal, Hou Xianjun, Richard Fiifi Turkson, and Muhammad Ezzat. "An analytical study of tribological parameters between piston ring and cylinder liner in internal combustion engines." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 230, no. 4 (August 3, 2016): 329–49. http://dx.doi.org/10.1177/1464419315605922.

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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 dry 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 boundary lubrication modes to obtain minimum friction between rings and liner and to ultimately help in improving the performance of engines.

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3

ADAMKIEWICZ, Adam, and Jan DRZEWIENIECKI. "OPERATIONAL EVALUATION OF PISTON-RINGS-CYLINDER LINER ASSEMBLY WEAR IN HIGH POWER MARINE DIESEL ENGINES." Tribologia 271, no. 1 (February 28, 2018): 5–15. http://dx.doi.org/10.5604/01.3001.0010.6357.

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This paper presents an operational evaluation of piston-piston rings-cylinder liner (PRC) assembly wear in marine diesel engines of high power. It is based on visual inspection through cylinder liner scavenge ports. Clearance measurements of piston rings in piston grooves and piston ring gap measurements were used to evaluate the extent of wear of the PRC assembly. Moreover, it is shown that piston ring gap measurements can be used as a reference parameter in wear trend analysis to predict the length of time periods between overhauls (TBO). Furthermore, it has been shown that controlling the wear of chromium (protective) layers of piston ring working surfaces by measuring their thickness with induction and eddy current methods is highly useful. They were accepted as a source of information on PRC lubrication correctness and as a symptom of its technical condition. Factors indicating the necessity of an overhaul and introducing operational methods of improving working conditions between the tribological pair – liner and piston rings have been determined.

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4

Peng, Engao, and Sheng Huang. "Wear performance of cylinder liner surface texturing on cylinder liner–piston ring assembly." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, no. 3 (June 15, 2017): 291–306. http://dx.doi.org/10.1177/1350650117713435.

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The microgeometrical structure has a great impact on lubricating performance of the cylinder liner–piston ring assembly. Extensive investigations have been done upon the various texture types for better lubrication. However, rarely do they focus on the morphological alteration of the friction surfaces during the initial wearing process. In this study, the pits and grooves at the liner inner surface are processed and experiments are conducted to investigate the influence of the surface texturing structure on the piston ring assembly during the initial wearing process at different rotating speeds. Then, the tribology information of cylinder liner–piston ring assembly is obtained and the mechanism between surface texturing structure and lubricating performance was analyzed. Experimental results show that some pits and grooves on the inner surface of the cylinder liner can properly improve the wear performance of cylinder liner–piston ring at a high rotating speed in diesel engine, and hence reducing friction and wear. Moreover, it provides experimental data for theoretical analysis and knowledge for improving the friction surface texturing of cylinder liner.

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5

Zavos, Anastasios, and Pantelis G. Nikolakopoulos. "Measurement of friction and noise from piston assembly of a single-cylinder motorbike engine at realistic speeds." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 13 (November 14, 2017): 1715–35. http://dx.doi.org/10.1177/0954407017734770.

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This paper presents a thorough experimental study of piston assembly friction and noise in a single-cylinder motorbike engine operating at low speeds. The friction of the piston ring pack is evaluated using a foil strain gauge with minimal cylinder modification on the thrust side. The technique involves transmitting deformations through the cylinder bore and recording reflections from the lubricated interface as the piston assembly passes. Under these conditions, the piston side forces and the thermal deformations on the output side of the strain gauge sensor are critical. Therefore, the proposed methodology is designed under controlled operating conditions. The overall deformation of the piston assembly is analysed to measure the primary reflection due to friction between the piston assembly and the cylinder wall. Simultaneously, the piston assembly noise is recorded on the thrust side of the engine block using a microphone. Taking measured noise data into account, possible piston slap events resulting from varied engine speeds are taken into account using continuous wavelet signal analysis. The calibration procedure for both tests is also illustrated. The measured friction results show that the strain gauge technique is a challenging work in providing realistic results to enhance current technology. For low engine speeds, a higher contribution is noted by boundary friction at the top dead centre reversal, extending to the position of maximum combustion pressure in the power stroke. Furthermore, the main contribution of the piston slap is estimated at the thrust side when the piston assembly passes at the beginning of the combustion stroke. These results can also be attributed as data to validate piston ring models in terms of friction and piston slap.

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6

Srinivas, E. Krishna. "Design and Analysis of Piston Rings by Using Hyper Elastic Materials of Dynamic Engine Assembly." International Journal for Research in Applied Science and Engineering Technology 9, no. VII (July 20, 2021): 1808–15. http://dx.doi.org/10.22214/ijraset.2021.36704.

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The piston ring is one of the main components of an internal combustion engine. Its main purposes are to seal the combustion chamber of engine. The main objective of this work is to develop the design modeling and then analysis of stress and deformation of the piston rings by using different materials like Grey cast iron, elastomer and Titanium alloy by using ansys software and to investigate these three materials behavior which are used for the piston ring. The project shows the components involved in the single cylinder engine assembly and their operation. Finally we are checking out three materials behaviors which are used for piston rings. This research paper deals with to reduce the friction of a piston ring while maintaining a Large oil film load-carrying capacity, an approach comprising of the inverse method, modeling and analysis of piston rings using Structural and rigid dynamics is deliberated in order to quantify the stress that the rings can bear. Many researchers had considered that the entire surface of the ring was enveloped in an oil film, but much experimental research has discovered that not all the entire surface was soaked. The various parameters studied under structural analysis are displacement and ultimate stress limit using three Different composition materials. A cumulative analysis is performed which considers the combined effect of mechanical and load for determination of the dimensions of the rings.

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7

Tee, J. W., S. H. Hamdan, and W. W. F. Chong. "Predictive tool for frictional performance of piston ring-pack/liner conjunction." Journal of Mechanical Engineering and Sciences 13, no. 3 (September 27, 2019): 5513–27. http://dx.doi.org/10.15282/jmes.13.3.2019.19.0445.

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Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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8

Liu, K., Y. B. Xie, and C. L. Gui. "A comprehensive study of the friction and dynamic motion of the piston assembly." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 212, no. 3 (March 1, 1998): 221–26. http://dx.doi.org/10.1243/1350650981542038.

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A mixed lubrication model based on a two-dimensional average Reynolds equation is presented in this paper. It is developed for use in conjunction with a piston secondary motion analysis. The motion has been studied and the effects of structure parameters and different profiles of piston skirts on the motion are also investigated. The friction force and power loss consisting of piston skirt friction and the friction of the piston ring pack are also given.

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9

Burnett, P. J., B. Bull, and R. J. Wetton. "Characterization of the Ring Pack Lubricant and its Environment." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 209, no. 2 (June 1995): 109–18. http://dx.doi.org/10.1243/pime_proc_1995_209_413_02.

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The performance characteristics of the piston ring-liner assembly and the lubricant within it are critical for the operation of modern internal combustion engines. The ring pack can directly affect engine friction, oil consumption and oil degradation, which in turn can impact upon fuel economy, emissions and engine wear. The operation of this system is complex and no single technique is capable of fully characterizing the processes occurring. This paper outlines the range of both experimental and theoretical methods that are being applied to the study of this system and the lubricant within it. These include the modelling of ring pack gas and oil flows, and direct measurement of piston temperatures, ring belt pressures and piston ring motion. Characterization of lubricant degradation via direct sampling of oil from the top ring groove of an operating engine has also been used. The merits of such a multi-faceted approach are discussed in relation to piston deposit formation.

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10

Ma, M.-T., I. Sherrington, and E. H. Smith. "Analysis of lubrication and friction for a complete piston-ring pack with an improved oil availability model: Part 1: Circumferentially uniform film." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 211, no. 1 (January 1, 1997): 1–15. http://dx.doi.org/10.1243/1350650971542273.

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The study of the tribological performance of piston rings plays an important role in piston assembly design. In this study, a comprehensive analysis of piston-ring pack lubrication has been developed. The model employs a flow-continuity algorithm and considers relative ring locations in the piston-ring pack as well as oil accumulation in front of the ring in determining the oil availability. The computer model is able to predict the effect that bore distortion and ring conformability have on piston-ring performance. (This influence is discussed in Part 2 of the paper). In this part of the paper (Part 1), the theoretical formulation of the model is briefly described. The model is verified through comparison of the calculated ring-liner film thicknesses with those measured experimentally by Hamilton and Moore on a diesel engine. Then some results, obtained under situations where film thicknesses are circumferentially uniform, are presented to simulate a piston-ring pack in a modern petrol engine as an example to demonstrate the capabilities of the model and to show the effects of some important factors on the performance characteristics of the ring pack. The authors have found that the model developed is a robust one which can be used to analyse the tribological performance of ring packs effectively in both circular and distorted cylinder bores of internal combustion (IC) engines.

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11

Rozario, Arthur, Christoph Baumann, and Raj Shah. "The Influence of a Piston Ring Coating on the Wear and Friction Generated during Linear Oscillation." Lubricants 7, no. 1 (January 14, 2019): 8. http://dx.doi.org/10.3390/lubricants7010008.

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The piston group is responsible for contributing to ~50% of the frictional losses of an engine, which ultimately leads to the waste of fuel. This coupled with the fact that gasoline is a finite resource linked to CO2-emissions, there is an increased demand of higher performance vehicles, which coincidently further loads the piston ring. As of yet, there are plenty of studies that already study the piston ring’s contact with the cylinder liner. However, this study focuses on a cost-effective Schwing, Reib, Verschleiss (SRV) instrumentation that allows to pre-screen lubricants, additives, materials and coatings for their friction, wear and load carrying capacity including scuffing resistance. As a result of the pre-screening conducted outside of engine by using the SRV instrument, it brings us to the following conclusion: the PVD CrN-TiN 1º Group coating on the piston ring produces the least wear, as well as the lowest coefficient of friction. Moreover, it is concluded that a coating that is based from CrN and TiN allows the piston ring to perform better in engine settings. A continued understanding of the piston-cylinder-contact assembly only helps engineers, scientists and any other stakeholder to improve on the piston ring and cylinder liner interaction.

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12

BORKOWSKA, Joanna, and Andrzej KAŹMIERCZAK. "Research and analysis of the results from the tribotester test for piston." Combustion Engines 169, no. 2 (May 1, 2017): 14–17. http://dx.doi.org/10.19206/ce-2017-203.

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Piston – ring – cylinder assembly of combustion engine has a lot of friction pairs examples, also one of them which decide about fastness to wear, it means first sealing ring – cylinder, called further very simply ring – cylinder unit. During work of this unit we can observe wear of piston, precisely – of coating which is deposited on ring to prolong service life. Objective of this work was to realize a test of roll-block type on tribotester to set durability of piston sample. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of diamond coating technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials in friction pairs, including powders. The work aims to show the possibilities and benefits of the application of new protective coatings to reduce their wearing, which is consistent with the observed trend of technology development.

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13

Nakai, H., N. Ino, and H. Hashimoto. "Piston-Ring Lubrication Problems for Refrigeration Compressors Considering Combined Effects of Supply Oil Quantity and Surface Roughness." Journal of Tribology 118, no. 2 (April 1, 1996): 286–91. http://dx.doi.org/10.1115/1.2831297.

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Reciprocating-type compressors are widely used for refrigeration systems, and an understanding of piston-ring lubrication in the compressor is vital for designers in reducing the energy losses due to friction because a substantial portion of friction in the compressors is attributable to the piston-ring assembly. This study aimed at developing a one-dimensional analysis for lubrication between the piston-ring and cylinder of refrigeration compressors considering the combined effects of supply oil quantity and surface roughness on piston-ring face and cylinder wall. In the theoretical model, the piston-ring is treated as a one-dimensional dynamically loaded bearing with combined sliding and squeezing motion. The one-dimensional modified Reynolds equation based on the average flow model by Patir and Cheng is used as a governing equation. In the analysis of the modified Reynolds equation, two-types of inlet boundary conditions, flooded condition and starvation condition, are applied at the leading edge according to the supply oil quantity, and the Reynolds boundary condition is applied at the trailing edge. A numerical procedure is then developed to estimate the cyclic variation of minimum film thickness, inlet and outlet positions of lubrication film and friction force, and the combined effects of supply oil quantity and surface roughness height are examined for a typical refrigeration compressor. It is clarified from the numerical results that the supply oil quantity and surface roughness affect significantly the friction force of the piston-ring for refrigeration compressors.

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14

Shih, L. K., and D. N. Assanis. "Effect of Ring Dynamics and Crevice Flows on Unburned Hydrocarbon Emissions." Journal of Engineering for Gas Turbines and Power 116, no. 4 (October 1, 1994): 784–92. http://dx.doi.org/10.1115/1.2906886.

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A significant source of unburned hydrocarbon emissions from internal combustion engines originates from the flow of unburned fuel/air mixture into and out of crevices in the piston-cylinder-ring assembly. During compression, fuel vapor flows into crevice regions. After top dead center, the trapped fuel vapor that returns into the cylinder escapes complete oxidation and contributes to unburned hydrocarbon emissions. In this work, the crevice flow model developed by Namazian and Heywood is implemented into KIVA-II, a multidimensional, reacting flow code. Two-dimensional, axisymmetric simulations are then performed for a 2.5 liter gasoline engine to investigate the effects of engine speed and selected piston-ring design parameters on crevice flows and on unburned hydrocarbon emissions. Results suggest that engine-out unburned hydrocarbon emissions can be reduced by optimizing the ring end gap area and the piston-cylinder side clearance.

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15

Rusu, Gabriela-Petruta, Mihai-Octavian Popp, Alexandru Bârsan, and Mihaela Oleksik. "Crimping Profile Optimization on the Air Spring Using Finite Element Method." ACTA Universitatis Cibiniensis 70, no. 1 (December 1, 2018): 43–47. http://dx.doi.org/10.2478/aucts-2018-0007.

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Abstract Due to the fact that the requirements of the industry aim to improve the dynamics, the safety and the comfort during the use of the vehicles, it is recommended to use the finite element method for component quality optimization. The purpose of this paper is to provide an overview of the current state of analysis through the finite element method of the crimping process used to assemble air springs produced in the automotive industry. Starting from the prototype of an air spring, the researches are focused on the study of the assembly of the piston with the bellow and the crimping ring through the crimping process. After analysis with the finite element method and static tests, improvements were made to the piston, the results of the tests revealing an improvement as opposed the original variant of the piston.

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16

Lyu, Fengxia, Caiqian Xie, Fengfeng Bie, Xinting Miao, Yifan Wu, and Ying Zhang. "Nonlinear Vibration Feature Recognition Method for Reciprocating Compressor Cylinder Based on VMD-Multifractal Spectrum." Shock and Vibration 2023 (January 17, 2023): 1–15. http://dx.doi.org/10.1155/2023/2504170.

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The failure probability of piston ring abrasion occupies the forefront in reciprocating compressor cylinder assembly. Due to the reciprocating friction between the piston ring and cylinder liner, the local vibration signal contains typical nonstationary characteristics with a seriously overlapped frequency band of impact signals, while the different featured signals are coupled with each other. Therefore, the identification of cylinder friction and abrasion fault modes has always been a hot and difficult problem in fault diagnosis of reciprocating compressors. In order to monitor the friction and abrasion between low linear speed nonmetallic piston ring and cylinder liner of reciprocating compressor in refinery and provide a theoretical basis for preventive maintenance, an analysis method based on VMD-multifractal spectrum was presented in this paper. First, the feasibility of the proposed method was proven based on the cylinder vibration experiment of a reciprocating compressor in the laboratory. Then, an in-service reciprocating compressor in a refinery was taken as the research object, from which the cylinder friction vibration signals were processed by using variational mode decomposition to obtain a band-limited intrinsic mode function (BLIMF). Multifractal detrended fluctuation analysis is employed in the final abrasion pattern identification. The results show that the proposed method based on VMD-multifractal spectrum analysis can effectively obtain the abrasion state of a piston ring, which can avoid blind overhaul or provide the basis for preventive maintenance and a practicable engineering route for the study of the piston ring abrasion degree.

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17

Ostapski, W., T. Wierzchoń, J. Rudnicki, and S. Dowkontt. "Simulation and bench studies of the constructively and technologically modernized high performance piston aircraft engine. Stage I." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 1 (February 1, 2017): 93–105. http://dx.doi.org/10.1515/bpasts-2017-0012.

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Abstract The paper presents an analysis of tribological wear of an assembly composed of cylinder liner and piston rings in a piston aircraft engine. In place of the previously used technology of gas nitriding of the cylinder liner (made out of 38CrAlMo6‒10 steel), formation of multi-component or composite layers by nitriding in plasma discharge environment was proposed. Also, a modification of the previously used chromium coating of the piston rings by plasma nitriding was proposed. A study on the structure and properties of surface layer diffusion manufactured by utilizing the phenomenon of cathode sputtering was carried out. Wear resistance tests were performed on a specially designed bench, with the use of isotope markers. Verification of each of the friction couples was based on using the wear of the ring as a function of the distance trip, and the roughness of the cylinder liner and ring.

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18

Dellis, P., and C. Arcoumanis. "Cavitation development in the lubricant film of a reciprocating piston-ring assembly." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 218, no. 3 (March 2004): 157–71. http://dx.doi.org/10.1243/1350650041323340.

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19

SERDECKI, Wojciech, and Piotr KRZYMIEŃ. "Distribution of piston compression ring pressure against the deformed cylinder wall." Combustion Engines 145, no. 2 (May 1, 2011): 17–24. http://dx.doi.org/10.19206/ce-117096.

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The following study presents typical cylinder deformations that come up during engine assembly and operation and provides results of analysis of how these changes affect the operation of the compression ring. Special attention has been paid to the effect of cylinder diameter increase on the distribution of the circumferential wall pressure and the cause of light gaps formation has been explained. The analyses presented in the following paper have been carried out using a computer program that has been formulated based on a compression ring mathematical model. Exemplary results of simulation have been obtained for a medium speed generator engine of a cylinder diameter of 0.48 m.

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20

Henein, Naeim A., Shengqiang Huang, and Walter Bryzik. "A New Approach to Determine Lubrication Regimes of Piston-Ring Assemblies." Journal of Tribology 119, no. 4 (October 1, 1997): 808–16. http://dx.doi.org/10.1115/1.2833889.

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A new approach is developed to determine piston-ring assembly lubrication regimes from the instantaneous frictional torque measured for the whole engine. This is based on the variation of the friction coefficient with the duty parameter in the Stribeck diagram over the mixed and hydrodynamic lubrication regimes. The derived equation determines the lubrication regimes from the slope of the line in the Stribeck diagram. A single cylinder spark ignition engine was instrumented to determine the total instantaneous frictional torque of the engine. Experiments were conducted under different loads at a constant speed. Results show that the regime is mixed lubrication near the top dead center (TDC) and shifts to the hydrodynamic lubrication regime as the piston moves away from TDC. The extent of the mixed lubrication regime depends on engine load and speed.

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21

Zhao, Jianguo, Hanxiu Peng, Shiji Fang, Kunpeng Wang, Shuo Han, Ying Zhang, Zixu Zhu, and Chi Tu. "Study on dynamic sealing performance of combined sealing structure of telescopic type of downhole robot by using HTHP coupling method." Science Progress 104, no. 3 (July 2021): 003685042110132. http://dx.doi.org/10.1177/00368504211013214.

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The sealing performance will directly affect the operation of downhole robot under HTHP condition. Traditional analysis methods of sealing performance are that the temperature and pressure is loaded respectively. This can not really evaluate the sealing performance. Besides, the simulation process is: Step 1: pre-compress O-ring to produce contact force. According to the contact pressure, select the compression ratio to calculate the displacement of the slip ring. Step 2: load fluid pressure on the O-ring. This simulation method is to directly load pressure on the undeformed O-ring. However, the O-ring will deform after pre-compression. Therefore, this simulation method is not accurate. In order to make the simulation data more accurate, calculate the data of shape, stress, and strain of O-ring caused by pre-compression caused by assembly. Then, import the deformation body containing the real data of shape, stress, and strain into a new model. On the basis, establish the numerical simulation model of piston, piston guide rod, O-ring, and FTS-ring with HTHP loads is. Finally, calculate and analyze. When the compression ratio of the O-ring is about 14%, the sealing performance is good. What’s more, the distribution of contact stress and Von Mises of the O-ring at 8.3 mm/s of motion speed are analyzed. The results show that the foot shaped combined sealing structure can keep a good dynamic sealing performance under HTHP condition. This paper provides a theoretical basis for the analysis of the dynamic sealing performance by using HTHP coupling method. In the analysis of sealing performance: the hydraulic pressure is loaded to the real model with the real shape, stress, and strain produced by the O-ring assembly. This can more accurately evaluate the sealing performance under HTHP condition. It also provides a reference for the dynamic sealing structure design of downhole tools.

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22

Kula, Piotr, Robert Pietrasik, Sylwester Pawęta, and Jarosław Komorowski. "INDUSTRIAL SCALING OF LOW-FRICTION HYBRID LAYER TECHNOLOGY ON PISTON RINGS." Tribologia 302, no. 4 (December 30, 2022): 23–29. http://dx.doi.org/10.5604/01.3001.0016.1605.

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Technological trials of gas sulphonitriding processes for cast iron piston rings were carried out as an alternative to chromium electroplating for the production of low-friction layers. The effectiveness of different ways of packing heat treatment charges in minimising or eliminating deformation of the rings was compared, and the effectiveness of ring packing with restraining tooling was confirmed. The maximum duration of the gas sulphonitriding process was determined at 1 hour, both as a stand-alone process and as a component process in a multi-stage technology for the manufacture of low-friction hybrid layers, ensuring the maintenance of sufficient ring toughness for an opening during assembly.

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23

Ostapski, W., T. Wierzchoń, J. Rudnicki, and S. Dowkontt. "Erratum to: Simulation and bench studies of the constructively and technologically modernized high performance piston aircraft engine. Stage I." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 2 (April 1, 2017): 273–75. http://dx.doi.org/10.1515/bpasts-2017-0031.

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Abstract In Ostapski et al., Bull. Pol. Ac.: Tech 65(1), 93-105 (2017), doi: 10.1515/bpasts-2017-0012, an analysis of tribological wear of an assembly composed of cylinder liner and piston rings in a piston aircraft engine was presented. In place of the previously used technology of gas nitriding of the cylinder liner (made out of 38CrAlMo6-10 steel), formation of multi-component or composite layers by nitriding in plasma discharge environment was proposed. Also, a modification of the previously used chromium coating of the piston rings by plasma nitriding was proposed. A study on the structure and properties of surface layer diffusion manufactured by utilizing the phenomenon of cathode sputtering was carried out. Wear resistance tests were performed on a specially designed bench, with the use of isotope markers. Verification of each of the friction couples was based on using the wear of the ring as a function of the distance trip, and the roughness of the cylinder liner and ring. This note corrects flaws in illustrations published in the original paper.

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24

Yun, Jeong Eui, and Sung Soo Kim. "New Device for Piston-Ring Assembly Friction Force Measurement in IDI Diesel Engine." JSME International Journal Series B 36, no. 4 (1993): 723–29. http://dx.doi.org/10.1299/jsmeb.36.723.

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25

Chaudhari, Tejaskumar, and Bharatkumar Sutaria. "Investigation of friction characteristics in segmented piston ring liner assembly of IC engine." Perspectives in Science 8 (September 2016): 599–602. http://dx.doi.org/10.1016/j.pisc.2016.06.032.

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26

Ma, Zheng, Naeim A. Henein, Walter Bryzik, and John Glidewell. "Break-In Liner Wear and Piston Ring Assembly Friction in a Spark-Ignited Engine." Tribology Transactions 41, no. 4 (January 1998): 497–504. http://dx.doi.org/10.1080/10402009808983774.

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27

Grabon, Wieslaw, Pawel Pawlus, Slawomir Wos, Waldemar Koszela, and Michal Wieczorowski. "Evolutions of cylinder liner surface texture and tribological performance of piston ring-liner assembly." Tribology International 127 (November 2018): 545–56. http://dx.doi.org/10.1016/j.triboint.2018.07.011.

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28

YUN, Jeong Eui, and Sung Soo KIM. "An Improved Approach to the Instantaneous IMEP Method for Piston-Ring Assembly Friction Force Measurement." JSME international journal. Ser. 2, Fluids engineering, heat transfer, power, combustion, thermophysical properties 35, no. 2 (1992): 310–18. http://dx.doi.org/10.1299/jsmeb1988.35.2_310.

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29

Lyubarskyy, Pavlo, and Dirk Bartel. "2D CFD-model of the piston assembly in a diesel engine for the analysis of piston ring dynamics, mass transport and friction." Tribology International 104 (December 2016): 352–68. http://dx.doi.org/10.1016/j.triboint.2016.09.017.

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30

Nouri, Jamshid, Ioannis Vasilakos, Youyou Yan, and Constantino-Carlos Reyes-Aldasoro. "Effect of Viscosity and Speed on Oil Cavitation Development in a Single Piston-Ring Lubricant Assembly." Lubricants 7, no. 10 (October 9, 2019): 88. http://dx.doi.org/10.3390/lubricants7100088.

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A high-speed camera has been used to produce unique time-resolved images of high quality to describe the dynamics of the lubricant flow and cavitation characteristics in a sliding optical liner over a fixed single piston-ring lubricant assembly for three lubricants with different viscosities to establish their impact on cavitation formation and development. The images were obtained at two cranking speeds (or liner sliding velocity) of 300 rpm (0–0.36 m/s) and 600 rpm (0–0.72 m/s), at a lubricant temperature of 70 °C and a supply lubricant rate of 0.05 L/min. A special MATLAB programme has been developed to analyse the cavitation characteristics quantitatively. The dynamic process of cavities initiation was demonstrated by time-resolved images from fern cavity formation to fissure cavities and then their development to the sheet and strings cavities at a liner sliding velocity of around 0.17 m/s. The results for both up- and down-stroke motions showed that the cavities reach their fully developed state downstream of the contact point when the liner velocity reaches its highest velocity and that they start to collapse around TDC and BDC when the liner comes to rest. Within the measured range, viscosity had a great influence on length of cavities so that a decrease in viscosity (from Lubricant A to C) caused a reduction in length of cavities of up to 35% for Lubricant C. On the other hand, an increase in speed, from 300 rpm to 600 rpm, have increased the number of string cavities and also increased the length of cavities due to thicker oil film thickness with the higher speed. Overall, the agreement between the processed data by MATLAB and visualisation measurements were good, but further thresholds refinement is required to improve the accuracy.

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31

Rakosi, Edward, Gheorghe Manolache, Sorinel Gicu Talif, and Dan Teodor Balanescu. "COSRING-LUJET, Integrated New Concept in Automotive I.C. Engines for a Better Lubrication." Applied Mechanics and Materials 659 (October 2014): 231–36. http://dx.doi.org/10.4028/www.scientific.net/amm.659.231.

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The COSRING-LUJET is a new concept for integrated solution to improve the lubrication regime in internal combustion engines. Introducing a conical shape for the peripheral surface of the rings, the authors analyze the conditions for the lubrication regime. Under this new concept, entitled COSRING, has developed a method for determining the transversal profile of the first and the second compression ring in order to obtain a better lubrication conditions for the piston ring – cylinder line assembly. On the other hand, the authors analyze the main factors affecting the cam-follower contact conditions, emphasizing the influence of the lubrication regime conditions over the couple wear reduction. The LUJET concept, proposed and studied by the authors, is an original solution for the improvement of the lubrication regime and engine life by using additional oil jets directed over the contact area.

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32

Tomanik, Eduardo, Francisco Profito, Brett Sheets, and Roberto Souza. "Combined lubricant–surface system approach for potential passenger car CO2 reduction on piston-ring-cylinder bore assembly." Tribology International 149 (September 2020): 105514. http://dx.doi.org/10.1016/j.triboint.2018.12.014.

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33

Dardalis, Dimitrios, Amiyo Basu, Matt J. Hall, and Ronald D. Mattthews. "The Rotating Liner Engine (RLE) Diesel Prototype: Reducing Internal Engine Friction by about 40% under Idle Conditions." Applied Sciences 11, no. 2 (January 15, 2021): 779. http://dx.doi.org/10.3390/app11020779.

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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.

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34

Grabon, Wieslaw, Pawel Pawlus, Slawomir Wos, Waldemar Koszela, and Michal Wieczorowski. "Effects of honed cylinder liner surface texture on tribological properties of piston ring-liner assembly in short time tests." Tribology International 113 (September 2017): 137–48. http://dx.doi.org/10.1016/j.triboint.2016.11.025.

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35

Messé, S., and A. A. Lubrecht. "Transient elastohydrodynamic analysis of an overhead cam/tappet contact." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 214, no. 5 (May 1, 2000): 415–25. http://dx.doi.org/10.1243/1350650001543296.

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The friction in automotive engines is mainly caused by three components: the engine bearings, the piston-ring assembly and the valve train. In order to improve reliability and performance and to reduce fuel consumption, manufacturers have to reduce engine friction. To do this a better understanding of these components is necessary. In this paper, the valve train is studied for a direct-acting system. A transient elastohydrodynamic lubrication analysis is developed. The model includes the variation in the radius of curvature of the cam, the variation in the hydrodynamic velocity and the variation in the load. The film thickness is calculated as a function of time and space. In order to reduce the computing time, multi-grid and multi-level multi-integration techniques are used. Results show squeeze-film effects and ejection of lubricant on hydrodynamic speed reversion.

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36

Zhu, Yu Feng. "Development of the WW-1.65/7 Oilless Compressor." Advanced Materials Research 753-755 (August 2013): 1499–502. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1499.

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The development was made about the WW-1.65/7 oilless compressor in order to meet market demand. The oilless lubrication of the compressor is obtained by using self-lubricating materials and grease lubrication bearings. The reasonable structure of the piston component, its perfect seal effect and long life are achieved by the exact design and correct assembly. The air-cool pattern and the full opened crankcase bottom make the compressor cooled better, the cost is low. By analysis and calculation, the important structure parameters are made that the speed is 800r/min, the radius-length ratio is 1/6.6 and the axial width of the guiding ring is 50mm, these provide the important guarantee for the run reliability and life of the compressor. The WW-1.65/7 oilless compressor has better properties, can run reliably and go into mass production already.

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37

KAŁUŻNY, Jarosław, Jerzy MERKISZ, Aleksander STEPANENKO, Emil WRÓBLEWSKI, Bartosz GAPIŃSKI, Adam PIASECKI, and Dawid GALLAS. "Piston assembly in the most powerful 2.0l diesel engine – case study of the current tribological system and innovative concepts for the future." Combustion Engines 171, no. 4 (November 1, 2017): 127–33. http://dx.doi.org/10.19206/ce2017-421.

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This article is a contribution to the ongoing debate on the scenario of the vehicle powertrains development. The directions of the internal combustion engines development in search of the possibility of effective economic and ecological indicators improvement have been indicated. It has been pointed out that this goal can be achieved through the use of nanotechnology in order to exceed the downsizing barriers resulting from the permissible mechanical loads for conventional materials. The article presents the study of the construction and materials used in the piston assembly of the most advanced four-cylinder, compression-ignition diesel engine currently in manufacture. Original concepts of nanotechnology have been proposed to reduce friction losses in major friction components of future engines with extremely high loads. The main idea is to verify the hypothesis that the sub-micron surface texture of the friction components obtained in the process of applying anti-wear outer layers can lead to an effective reduction of friction losses under real engine operating conditions. Computer simulations of the effects of introducing the surface texture in the upper sealing ring on friction loss confirm this hypothesis by showing friction value being reduced by 3-4% relative to the standard ring profile. In the summary, further advanced technologies designed to effectively utilize the unique properties of carbon nanotubes have been described.

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38

Ali, Mohamed Kamal Ahmed, Hou Xianjun, Liqiang Mai, Cai Qingping, Richard Fiifi Turkson, and Chen Bicheng. "Improving the tribological characteristics of piston ring assembly in automotive engines using Al2O3 and TiO2 nanomaterials as nano-lubricant additives." Tribology International 103 (November 2016): 540–54. http://dx.doi.org/10.1016/j.triboint.2016.08.011.

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39

Gunawan, Subroto, and Panos Y. Papalambros. "A Bayesian Approach to Reliability-Based Optimization With Incomplete Information." Journal of Mechanical Design 128, no. 4 (January 25, 2006): 909–18. http://dx.doi.org/10.1115/1.2204969.

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In engineering design, information regarding the uncertain variables or parameters is usually in the form of finite samples. Existing methods in optimal design under uncertainty cannot handle this form of incomplete information; they have to either discard some valuable information or postulate existence of additional information. In this article, we present a reliability-based optimization method that is applicable when information of the uncertain variables or parameters is in the form of both finite samples and probability distributions. The method adopts a Bayesian binomial inference technique to estimate reliability, and uses this estimate to maximize the confidence that the design will meet or exceed a target reliability. The method produces a set of Pareto trade-off designs instead of a single design, reflecting the levels of confidence about a design’s reliability given certain incomplete information. As a demonstration, we apply the method to design an optimal piston-ring/cylinder-liner assembly under surface roughness uncertainty.

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40

KOSZAŁKA, Grzegorz, Michał GĘCA, and Andrzej SUCHECKI. "Simulation research into the influence of the combustion chamber blowby on the efficiency of a diesel engine." Combustion Engines 158, no. 3 (July 1, 2014): 73–79. http://dx.doi.org/10.19206/ce-116939.

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Combustion chamber leakage, caused mainly by blowby, results in a reduced engine performance and higher fuel consumption. The blowby rate is, to some extent, determined by the design of the piston-ring-cylinder assembly (PRC) and the blowby rate varies throughout the life of an engine due to wear of the said assembly. The paper presents a quantitative evaluation of the influence of the combustion chamber blowby on the engine performance and fuel consumption on the example of two diesel engines: older generation naturally aspirated indirect injection diesel engine and a modern turbocharged direct injection engine. The assessment was made based on a simulation research using the AVL Boost software and the input data for the calculations were ascertained based on measurements performed on actual objects. The results have shown that a reduction of the blowby by half compared to the values occurring in engines of good technical condition would increase the maximum torque and power by approx. 0.5% for both investigated engines. The results of the simulation have also shown that increases in the blowby occurring in engines after long service lead to increased fuel consumption from 1% to 7% and the lower the engine speed and load the greater theses values.

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41

DELLIS, Polychronis S. "TEMPERATURE EFFECT IN MINIMUM OIL FILM THICKNESS MEASUREMENTS IN A SIMPLIFIED SINGLE-RING TEST RIG USED TO SIMULATE THE PISTON-CYLINDER ASSEMBLY." Proceedings on Engineering Sciences 1, no. 1 (May 2019): 508–17. http://dx.doi.org/10.24874/pes01.01.067.

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42

Duarte Forero, Jorge, Guillermo Valencia Ochoa, and Jhan Piero Rojas. "Effect of the Geometric Profile of Top Ring on the Tribological Characteristics of a Low-Displacement Diesel Engine." Lubricants 8, no. 8 (August 11, 2020): 83. http://dx.doi.org/10.3390/lubricants8080083.

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The present study aims to analyze the influence of the geometric profile of the compression ring on the tribological properties of the lubricant. Additionally, the influence of the rotation speed and the engine load on the state of the lubricant is evaluated. For this study, a single-cylinder diesel engine is taken as the basis, from which a CAD model of the combustion chamber-piston assembly was made. In addition, the conditions in the cylinder chamber were analyzed when the engine operates at a rotation speed of 3000, 3300, 3600, and 3900 rpm, and a load of 1.5, 3.0, 4.5, and 6.0 N. The calculations were developed using the OpenFOAM® simulation software. The results obtained show that changes in the geometric profile of the ring can contribute to reducing the hydrodynamic friction force by 13% and the friction force caused by roughness by 61%. This implies a decrease in the power lost by friction. In general, the modification of the geometric profile allowed a reduction of 21% in the lost power associated with friction. Additionally, it was observed that the shape of the profile allows to reduce the pressure in the lubricant by 65% and obtain a greater thickness of the lubrication film. On average, an increase of 300 rpm and 1.5 N in the speed and load of the engine causes the friction force and power losses to increase by 45% and 10%. The above results imply that the geometric profile of the compression ring can improve tribological performance in the engine, allowing a reduction in fuel and better lubricant performance.

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43

Rathod, Nishith R., and Jyoti Menghani. "Dry sliding wear behavior and its relation to microstructure of artificially aged Al-Si-Mg/TiB2 in situ composites." Metallurgical and Materials Engineering 28, no. 2 (June 30, 2022): 269–90. http://dx.doi.org/10.30544/824.

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Mechanical stir casting is utilized to produce an artificially aged Al-Si-Mg alloy, whereas halide slat (K2TiF6 and KBF4) synthesis is utilized to produce Al-Si-Mg/TiB2 aluminum matrix composites. The dry sliding pin on disc wear test was conducted using a DUCOM/TR-20LE-PHM-200 machine to simulate an automobile application (Piston-Ring assembly). Where pistons are made of aluminum alloy (for the Pin) and rings are made of grey cast iron (for the disc material). At room temperature, a wear test was conducted by altering the ageing time (3, 6, 9, 12), sliding speed (2, 2.5 m/s), and applied load (14.71, 19.62, 24.52 N) with the disc speed (500 rpm) held constant (10 min). The results indicate that the aluminum matrix composite (AMC) wear rate is reduced by 37 percent at higher sliding speeds (2.5 m/s) and by 4 percent at lower sliding speeds (2.0 m/s) compared to the base alloy. Field emission scanning electron microscope-energy dispersive spectroscopy (FESEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis revealed that the formation of the mechanically mixed layer (MML) or oxidative layers on the worn surfaces reduces the wear rate under conditions of longer ageing time, higher sliding speed, and lower applied load. The research demonstrates that composite wear is a function of sliding velocity, aging period, and applied force. As sliding speed rose from 2 m/s to 2.5 m/s, the wear rate of composites dropped reasonably, yet composites are softer than basic alloys. It is conceivable due to the presence of a considerable amount of MML and the formation of oxidative layers between pins and their equivalents.

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44

Michalski, Jacek, and Paweł Woś. "Thermo-mechanical analysis of stress and deformation of engine cylinder block assembly as the attempt to explain an uncontrolled ignition of air-fuel mixture." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 6 (June 30, 2018): 609–18. http://dx.doi.org/10.24136/atest.2018.143.

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The paper analyzes the possible cause of self-ignition of air-fuel mixture in spark-ignition internal combustion engine loaded with maximum power during tests on the engine dynamometer stand. It leads to incorrect engine operation and may also occur during the flight of an aircraft or helicopter. In order to explain the cause of incorrect engine operation, a non-linear analysis using the finite element method was applied. A discreet model of a simplified engine cylinder assembly system comprising a cylinder body and the liner was determined. The numerical analysis includes both the mechanical force resulting from loading the cylinder liner clamp in the body as well as the pressure of the working medium pressure and the load on the non-uniform temperature field taken from engine test-bed measurements. The results of nonlinear static analysis of stresses and strains for the cylinder body-liner connection have shown that in the area of TDC where outer piston ring turns back, high stresses and plastic deformation of the cylinder liner occurr, causing a lack of contact between these elements. This disrupts the heat transfer from the cylinder liner to the cylinder body and creates the possibility of uncontrolled ignition of the fuel-air mixture.

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45

Radaykina, Elena A., and Aleksandr V. Kotin. "REPAIR OF POWER HYDRAULIC CYLINDERS USING NEW POLYMER COMPOSITE MATERIALS." Tekhnicheskiy servis mashin 3, no. 144 (September 2021): 138–45. http://dx.doi.org/10.22314/2618-8287-2021-59-3-138-145.

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The development and implementation of a new repair technology based on the use of polymer parts made of high-performance antifriction composites in tribo-couplings of power hydraulic cylinders will reduce the cost and repair time, significantly increase the reliability of the entire hydraulic system. (Research purpose) The research purpose is in increasing the efficiency of repairing of power hydraulic cylinders of agricultural machinery by restoring tribo-conjugations with new antifriction composites based on modified caprolon. (Materials and methods) The article presents the study of the physical and mechanical characteristics of samples of polymer composites according to well- known and original methods. Authors used computer programs and original methods of equipment suppliers in the study of compounding processes, rheological and tribotechnical tests. Theoretical research using the provisions of theoretical mechanics, elasticity theory and thermophysics has been conducted. A numerical study of the introduction of a spherical indenter into a sample of a viscoelastic composite material was carried out using the ANSYS software package, the MAPDL module. (Results and discussion) The article analyzes the obtained data on the elastic-strength, rheological and tribotechnical characteristics of the studied compositions of polyamide composites. The three-component composite containing 2 percent shungite, 0.5 percent graphite, 6 surfactants has the best complex of these properties. It has been proposed to restore the operability of the piston assembly and the front cover during the repair of the power hydraulic cylinder to change their design with the installation of guide support rings made of polyamide composite into the cover and piston of the hydraulic cylinders. This will lead to a significant reduction in the wear rate of the tribo-coupling parts and reduce the complexity of repairing hydraulic cylinders. (Conclusions) Restoration of tribo-couplings of power hydraulic cylinders with the installation of a guide ring made of a new polymer composite ensures a decrease in the maximum contact stresses, the rate of their increase with an increase in the gap and, as a result, a decrease in the wear rate of the contacted parts.

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46

Potenza, R., J. F. Dunne, S. Vulli, and D. Richardson. "A model for simulating the instantaneous crank kinematics and total mechanical losses in a multicylinder in-line engine." International Journal of Engine Research 8, no. 4 (August 1, 2007): 379–97. http://dx.doi.org/10.1243/14680874jer00507.

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A two-degree-of-freedom dynamic model is constructed to simulate the instantaneous crank kinematics and total mechanical losses arising in a multicylinder gasoline engine coupled to a dynamometer. The simulation model is driven using specified cylinder gas pressures, and loaded by nominal brake torque and total friction losses. Existing semi-empirical torque loss models (based on calibrated single-cylinder diesel engine data) are used to account for the instantaneous friction losses in the piston-ring assembly, in bearings, and in auxiliaries. The model is specialized to the simulation of crank kinematics and matched brake torque for a three-cylinder in-line direct injection spark ignition (DISI) engine, without a gearbox. This allows the total friction loss to be separated from the brake torque for an engine not fitted with the very large number of sensors otherwise needed to calibrate analytical friction models. An equivalent simulation model is also constructed using GT-Crank, which excludes explicit reference to friction. In using both models to simulate steady state operation at a specified mean engine speed, the output torque is matched by iteration. The GT-Crank model necessarily compensates for internal losses by exaggerating the total output torque. Both simulation models are compared with measured crank kinematics and brake torque obtained from a dynamometer-loaded I3 DISI engine. The paper shows that by comparing the matched output torque from simulation with the measured output torque from the engine, the proposed model gives a very good high-speed prediction of the total mechanical losses. At low speed, the instantaneous model is still not accurate. It is also shown, however, that apart from the no-load condition, use of an average torque to compensate for friction (as in GT-Crank) is wholly acceptable for simulating instantaneous crank kinematics. This is the first reported instance of a simulation model (which includes the particular form of semi-empirical friction loading) being comprehensively compared and verified using multicylinder DISI engine data.

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47

CHAVDAROV ANATOLIY V., ANATOLIY V., and VYACHESLAV A. DENISOV VYACHESLAV A. "PROSPECTS OF USING MICROARC OXIDATION TECHNOLOGY FOR INTERNAL COMBUSTION ENGINES." Agricultural engineering, no. 5 (2020): 38–42. http://dx.doi.org/10.26897/2687-1149-2020-5-38-42.

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Анотація:

microarc oxidation (MAO) technology. The authors reveal an engine development tendency to replace cast-iron blocks and liners with aluminum ones with special coatings obtained by electroplating methods. It is noted that this method does not involve the use of repair technologies, which signifi cantly aff ects consumer costs. The paper shows the prospects of using MAO technology both in the manufacturing of engine parts and restoration operations. To assess the eff ectiveness of the proposed technology, practical study was performed on covering the working part of the cylinder used in small-size agricultural machinery. The engines were tested at 5.1 kW at 3,600 rpm for 300 hours. After testing, no defects or wear were found on the cylinder face. Preliminary test results of the assembled engine showed no loss of power over 10,000 hours of car mileage, which indicates that the geometric parameters of the parts are preserved. The authors emphasize that the most optimal combination is the friction pair of two parts with an MAO coating. It has been established that the introduction of nano-additives in a MAO-coating leads to a decrease in the coeffi cient of friction between the cylinder and the piston ring and reduces the wear of piston rings and the cylinder face in more than 10 times. A conclusion is made about the feasibility of introducing the considered technology into the mass production of engines and pistons, as well as developing a set of repair equipment.

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48

KOSZAŁKA, Grzegorz, Jacek HUNICZ, and Paweł KORDOS. "A research stand for the testing of the sealing properties of the piston-rings-cylinder assembly in a combustion engine." Combustion Engines 153, no. 2 (May 1, 2013): 54–62. http://dx.doi.org/10.19206/ce-117002.

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The paper discusses research assumptions and describes a test stand for the investigations of the sealing properties of the piston rings. The research stand includes an engine brake together with a control system, a research engine and a lubrication and engine thermal state stabilization systems. The engine was fitted with a research piston containing a measuring device enabling the recording of fast varying quantities such as the pressures in the space between the rings, axial displacements of the oil sealing rings in the piston grooves and the temperatures of the gas blown through the seal.

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49

Lu, Connie, Young-un Park, Konstantin Korotkov, Wei Mi, Stewart Turley, Veer Bhatt, Ripal Shah, and Wim Hol. "Multiple approaches towards understanding the type II secretion system." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C577. http://dx.doi.org/10.1107/s2053273314094224.

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Transport of folded proteins across membranes is a feat accomplished by few biomacromolecular machines. One of the machineries able to do so is the sophisticated type II secretion system (T2SS). It can translocate key virulence factors from the bacterial periplasm into the lumen of the gut of the human host. A prime example is the secretion of cholera toxin by Vibrio cholerae. The T2SS consists of ~12 different proteins, most of these present in multiple copies, organized into three subassemblies: (i) the Inner Membrane Platform; (ii) the Pseudopilus in the periplasm, which acts most likely as a piston pushing exoproteins through the outer membrane pore; (iii) the Outer Membrane Complex, allowing passage of ~100 kDa folded proteins. We have determined crystal structures from more than a dozen T2SS domains, yet, a full understanding of the architecture and mechanism of action of the T2SS remains a formidable challenge. Our approaches include the use of "assistant-multimers" to promote recalcitrant multimer formation and of nanobodies to overcome reluctant crystal formation. The Inner Membrane Platform is interacting with the secretion ATPase GspE which most likely needs to be hexameric for full activity. Full-length GspE co-crystallized with its major partner, the cytoplasmic domain of GspL, revealed a tremendous flexibility of this ATPase, and, most unexpectedly, also the organization of the same linear arrangement of cyto-GspL domains throughout three entirely different crystal forms. Two very different hexamers of GspE were elucidated by linking the GspE subunit to the subunit of Hcp1, which successfully acted as an "assistant hexamer", inducing hexamer formation by GspE. The dodecameric nature of the ~ 850 kDa GspD, the major component of the Outer Membrane Complex, evident in earlier electron microscopy studies, was observed in the dodecameric ring-like helix in crystals of its N-terminal domain. The contacts between GspD and the inner-membrane protein GspC will be discussed as well as the remarkably frequent occurrence of dimers of Inner Membrane Platform domains. How dimers are co-assembled with an ATPase hexamer with C6 symmetry and the Outer Membrane Complex dodecamer with C12 symmetry remains one of the many fascinating outstanding questions of the T2SS.

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50

"Piston ring with a multilayer assembly." Sealing Technology 2008, no. 12 (December 2008): 11. http://dx.doi.org/10.1016/s1350-4789(08)70607-x.

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