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This is a chapter from Mr. Clark's forthcoming book on “Marine Lubrication”, which we shall publish early next year. This book will be the most comprehensive work on this subject ever published and will deal with all aspects of lubrication of marine machinery.

The paper aims to investigate the friction and wear properties of three surface-modified piston rings matched with a chromium-plated cylinder liner.

Samples were taken from the chromium-plated cylinder liner, Cr-Al2O3 ring, CrN ring and Mo ring. Tribo-tests were conducted on a reciprocating sliding tribometer under fully formulated engine oils. Friction coefficients and wear depths of three friction pairs were tested. Surface morphologies of cylinder liners and piston rings before and after test were analyzed.

Experimental results show that in the Cr-Al2O3 piston ring, scuffing occurred easily when matched with the chromium-plated cylinder liner; compared with the Mo ring, the CrN ring could decrease the wear depth of the piston ring from 2.7 to 0.2 μm, and the wear depth of cylinder liner remained; however, the friction coefficient increased from 0.113 to 0.123. The tribological performances of three surface-modified piston rings were significantly different when they matched with chromium-plated cylinder liner.

Chromium-plated cylinder liner and the three kinds of surface-modified piston rings have excellent friction and wear properties, respectively. However, according to the systematic characteristics of internal combustion (IC) engine tribology, only the appropriate cylinder liner–piston ring can improve the tribological performance of the IC engine. This paper reports the tribological performance of three surface-modified piston rings matched with a chromium-plated cylinder liner. The results can be used as reference for the design of high-power-density diesel engine.

A self-adaptive piston is designed for the compressional gas cushion press nanoimprint lithography system. It avoids the lube pollution and high wear of traditional piston.

The self-adaptive piston device consists of symmetrical piston bodies, piston rings and other parts. The two piston bodies are linked by a ball-screw. The locking nut adjusts the distance between two piston bodies to avoid the piston rings from being stuck. The piston rings are placed between two piston bodies.

The simulation results based on COMSOL indicate that cylinder vibration caused by self-adaptive piston is 15.9 times smaller than the one caused by a traditional piston.

The self-adaptive piston is superior to the traditional piston in decreasing cylinder vibration.

This paper aims to propose a literature review of the main physical phenomena considered by previous studies focusing on the modelling and the numerical simulation of frictional behaviour of piston rings, in the first section. In the second section, the more recent technical papers and patents about piston ring pack are briefly discussed. They deal with novel materials, innovative manufacturing methods and modified shape for improving frictional, stability and blow-by behaviours.

This review paper aims at covering last period technical efforts about engine piston ring pack friction reduction through novel materials and manufacturing methods as well as new surface profiles according to the last outcomes of multiphysics numerical simulation.

The paper type is “literature review”. The findings of the authors of papers and patents are described.

This review paper proposes a survey of recent papers and patents on piston rings topic.

Ferric and ferrous oxides are used for coating of piston rings in order to obtain the layer, facilitating their wearing‐in at the beginning of work. This paper aims to present study and the implementation of the anti‐wear technology of piston rings production with the application of ferrous oxides. Those rings are intended for two‐stroke self‐ignited diesel engines used for driving the diesel locomotives.

It was decided to use magnetite, Fe₃O₄, together with a binding agent, sodium metasilicate. Working out the adequate technology of filling the grooves of piston rings required performing a broad research range. It is possible to apply three different technologies. In order to find out which of the three methods of filling grooves gives the best results, the series of experiments were planned.

Experimental results cover the variability intervals of input factors enabling the selection of their best combination by the analysis of the regression function. The paper describes the experimental plan for the wet technology with water‐glass, since it occurred to be the best considering the equipment of the factory in which it was implemented. In order to cover the variability field of input factors, the multifactor Hartley's plan was applied. On the basis of the performed investigations, it was found that all input factors are significantly influencing the filling quality of ring grooves on piston rings.

This technology in one of the Polish factories in piston rings production was implemented. The implemented technology allows the production of approximately 500,000 rings annually.

The paper presented a new anti‐wear technology of the sealing piston rings for diesel.

GRAPHITE, either alone or in combination with other materials, has long been used as a lubri‐cant for specific purposes, and in recent years the self‐lubricating property of carbon has been applied to the use of engineering components—such as carbon bearings and piston rings for compressors—constructed entirely of carbon.

THE fundamental requirements of a piston ring which must be fulfilled, if it is efficiently to perform its main function of acting as a seal against the passage of compressed gas between the cylinder and piston, are numerous and exacting.

The purpose of this paper is to review and to provide a dipper understanding of what happens to piston rings and cylinder surfaces when manufacturing errors depicted, such as waviness and straightness. The mechanism of friction and the piston ring structural integrity, due to the surface irregularities, are analyzed either for smooth ring surface or for artificial textured, while piston ring floats into the piston groove or not.

In this work two tribological models of a piston ring- cylinder package are presented using CFD analysis. Initially, the piston ring is considered as a secured ring in the groove of piston (secured ring) while in second model, the piston ring floats into the piston groove (free ring).

Increasing the number of waves across the piston ring thickness, the structural integrity of the ring is strongly influenced. Piston ring with surface texturing reduces the mean friction force, under the consideration of cylinder straightness. The gas leaks due to existence of the ring gap, affects significantly the maximum mechanical stresses.

The novelty of this paper is the analysis of manufacturing errors, such as waviness and straightness either for smooth or for artificial textured piston ring. In particular, the piston ring structural integrity investigated while chamber gas pressure leaks through the ring gap or not. The number of the waves, their amplitude and the fluid velocity are also taken into consideration.

The purpose of this paper is to underline the future need for OEMs to receive lowSAP, polymer‐ and metal‐free engine oils with high‐viscosity indices and to illuminate for other OEMs the technical feasibility for application of alternative engine oils based on esters or blends of hydrocarbons with esters or polyglycols.

The strategic goal depends technically on the use of intrinsic properties of alternative base fluids, thus substituing some additives, like anti‐wear, extreme pressure and viscosity index improvers. The prone wear resistance of novel triboactive/‐reactive materials enables higher portions of mixed/boundary lubrication generated by oils with a lower viscosity.

Overall, the different bionotox and low‐ash prototype engine oils with reduced additive contents displayed isoperformance regarding the tribological behaviour against cast iron and triboreactive materials. APS‐Ti_n−2Cr₂O_2n−1 displayed an overall wear resistance comparable with grey cast iron with high‐carbon content and liner wear reduction of one order of magnitude when mated with Mo‐based rings. Both tests confirmed the potential for substituing molybdenum‐based rings by APS‐Ti_n−2Cr₂O_2n−1. The most significant reduction in “system wear” down to “zero wear” was demonstrated by mating the APS‐Ti_n−2Cr₂O_2n−1 coated piston rings with smooth machined HVOF‐(Ti,Mo)(C,N) liner coatings.

As lubricants are today not part of the core business of automotive OEMs, the next steps have to be proposed by the petrochemical suppliers. It is recalled here that some OEMs in their history developed and produced lubricants.

The customer will appreciate any increase in longevity resulting in reduced maintenance. The OEM now owns, under increased solicitations, now a future‐oriented tool box in order to respond to environmental and CAFÉ demands with reasonable cost management.

This OEM report displays the complete methodology in order to adopt alternative engine oils in existing engine architectures.

IN this paper wear and tear is taken to mean not only wear of the liner but also of the piston ring assembly, and in the first part, published in the previous issue, the author wrote of a number of wear processes occurring separately or together. In Part II basic materials, stresses suffered by the engine in use and fuel combustion are considered.