Liner Assembly Research Articles

Evaluation of Tribological Properties of Different Coatings on Automotive Piston Rings: A Review

Friction and wear play crucial roles in automotive engine performances and their efficiency. Overall, 40% of fuel power loss occurs in friction of various components of the engine. Frictional loss between piston rings and cylinder liner assembly contributes major loss of fuel power in the automotive engine and it is about 15% of total fuel power loss occurs due to friction. In the present scenario, thin film coating techniques are in trend to enhance the mechanical and tribological properties of machine components. In this paper, different types of wear-resistant, corrosion-resistant, and antifriction coating materials and their characteristics are discussed. Also, carbon-based coatings, nitride coating, carbide coating, oxide coating, and the intermixing of counterparts of coating material to form a composite coating, multilayer coating, and varying their percentage elemental composition composite are reviewed and compared. The synergistic effect of coating with texturing over the piston ring is discussed. Finally, recent developments and new possibilities of coatings that can be employed on piston rings are briefly discussed.

Thermohydrodynamic Lubrication Characteristics of Piston Rings in Diesel Engine Considering Transient Heat Transfer under the Parameterized Surface Texture of Cylinder Liners

The cylinder liner and piston ring form the most crucial friction pair in the diesel engine, contributing 35–40% of its overall friction losses. Recent research indicates that transient heat transfer significantly affects piston ring lubrication. However, the impact of such a transfer on varying surface textures and lubrication traits remains unclear. This paper takes the piston ring–cylinder liner of a certain diesel engine as the research object, which is based on a two-dimensional averaged Reynolds function and Greenwood–Tripp micro convex body contact model; establishes a numerical calculation model of the transient heat fluid lubrication characteristics of a vertical piston ring–cylinder liner assembly by combining the oil film thickness equation, energy equation, lubricating oil viscosity–temperature, and viscosity pressure characteristics; avoids large errors associated with assuming different temperature values for lubricants; and also uses the cylinder liner surface texturing technique to examine the effects of surface texturing on lubrication properties in the presence of transient thermal fluids. The findings indicate that employing transient thermal fluid for determining the mean value of the oil film temperature in isothermal lubrication calculations yields comparable values for minimum oil film thickness and frictional power consumption, while the friction power consumption calculated by the transient thermal fluid is slightly lower. The depth of the recesses on the surface of the cylinder liner should be minimized, while the radius of the texture should be maximized, taking into consideration the current circumstances. Compared with a cylindrical texture, a spherical texture achieves lower friction with good lubrication indexes.

Study on lubrication performance of engine piston skirt with bionic design

As the main friction pair of engine, the friction loss of piston-cylinder liner assembly in the working process has become the main reason of engine friction power consumption. Many species in the biological world have formed non-smooth forms of resistance reduction after thousands of years of survival and evolution. Many people have applied this non-smooth shape of drag reduction on organisms to the surface of friction pairs in construction machinery. Based on LX108 engine, the wear and erosion resistance of Scapharca subcrenata surface is applied to the piston skirt, which is the main friction pair in the engine. Nine test schemes were designed according to orthogonal test. This design selects three factors, namely, groove distribution type, groove depth and width, groove spacing, and each factor includes three levels. The macroscopic fluid lubrication state of the whole piston skirt with bionic shape is studied. Through the change of oil film thickness caused by thermal-mechanical coupling deformation of skirt, combined with the average Reynolds equation, the hydrodynamic pressure of lubricating oil, shear stress, and skirt friction force are obtained to verify the contribution of bionic shape to piston drag reduction, wear reduction, wetting increase, and friction power consumption. The simulation and test results show that the lubrication of all parts of the bionic groove piston skirt is better than that of the standard piston; When the depth and width of groove is 0.8 mm and the spacing is 10°, the thicker the oil film thickness of skirt is; The bionic piston whose oil film bearing area is 74%–87% of the standard piston has the smallest normal pressure and friction; When the upper end of the skirt is arranged with groove shape and the lower end is arranged with narrow groove shape between wide grooves, the lubrication effect is better.

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.

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.

Cylinder liner wear as a function of selected physicochemical indicators of engine oil

The paper presents a new method of forecasting the durability of piston-rings-cylinder (PRC) liner assembly of the internal combustion engine on the basis of observed changes of physical and chemical properties of engine oil. Methods used so far for the durability evaluation of the PRC group required collecting information about the moments when the assembly reached its boundary state or used kinetic models of wear designed using accelerated research of real objects. In the proposed method, for the evaluation of durability of engine cylinders information gathered form engine oil is used. Course of changes of the proposed index of change intensity of kinematic viscosity at the temperature of 100°C – Cv100 allows for evaluation of the durability of PRC assembly of an IC engine. Obtained value was positively verified using forecasting method related to the technical criteria based on the assessment of the wear intensity.

Development of a floating liner test rig and lubrication model for the study of the piston compression ring friction force under fully flooded and starved lubrication

Advances in internal combustion engines make it necessary to study in depth their contribution to engine efficiency, and thus to friction mechanical losses, especially those generated in the piston-cylinder liner assembly. In this paper, the design of a novel test rig is presented, based on the floating liner principle, with the key objective of having the capability of developing multiple parameters tests in a relatively quick and easy way. The final design integrates a single-cylinder internal combustion engine, a mechanical solution that allows the liner to float, three piezoelectric force sensors and a novel design of lateral support based on ball transfer units. Reproducibility and repeatability of tests were assessed demonstrating the capability of the test rig to develop reliable friction measurements. Some parameters tests were developed to evaluate the sensitivity of the friction force measurements to variations in the working conditions, oil temperature and engine speed. A theoretical model for the piston compression ring is presented for both fully flooded and starved lubrication conditions, including asperity interactions and lubricant rheology. Comparisons of these approaches with experimental results showed that, for the working conditions of the test rig, lubrication of the compression ring is better estimated under fully flooded lubrication condition, as the starved lubrication analysis results in over-estimated friction force values at higher engine speed regimes.

Tailor-made design, fabrication and validation of SrO doped nanostructured ZTA ceramic Femoral head – Acetabular socket liner assembly

An established commercial grade SrO doped ZTA composition has been considered to design, fabrication through uniaxial pressing followed by sintering and polishing, validation of dimension, 3D surface profile, 3D microstructure, and compressive load bearing capacity of femoral head – acetabular socket liner prototypes for the hip prosthesis. While design and dimensions are concerned, both the steel (HRC60) molds were designed and machined to achieve precious dimensions of femoral head (FH; OD – 30 ± 0.01 mm) and acetabular socket liner (ASL; ID – 30.15 ± 0.01 mm). A close variation in the range of ±0.01 mm was confirmed the precision geometry of polished FH and ASL with consideration of 22 points coordinate measuring method (CMM). 3D surface profile ensures the surface characteristics of Ra = 0.2 ± 0.01 μm and Rq = 0.5 ± 0.01 μm for outer surface of FH and an inner surface of ASL, respectively. Structure integrity and fabrication defects including cracks and pores free bulk structures were confirmed by Micro CT. The compressive load resistance known as burst strength for independent FH and FH-ASL assembly were measured 16.2 KN and 17.6 KN, respectively. The developed ceramic prototypes have an economic advantage and can be adopted as artificial hip prosthesis after extensive in-vitro and in-vivo analysis.

Quality Control in the Machining of Cylinder Liners at Repair Enterprises

The use of the following quality-control instruments in the machining of cylindrical liners at repair shops is considered: Shewhart charts (of moving-range and individual-measurement types) and histograms for analysis of the adjustment precision. A monitoring checklist has been developed for determining the losses due to all defect types. Interchangeability among groups for piston–liner assemblies completely eliminates wasted inventory.

Рабочие режимы и ресурсные показатели дизелей 9L28/32А-F фирмы MAN-B&W в процессе длительной эксплуатации

The article describes L28/32 and L23\30 MAN-B&W diesel engines widely used by many shipping companies owing to high maintenance and service ability of simple, but sufficiently reliable engine parts. As for a medium speed 4-stroke engine, diesels have optimal power forcing characteristics, high fuel saving and durable overhaul time for essential parts. There have been considered the positive and negative features of the engine, which are also important technical indicators, in comparison with the designed samples when choosing the base engine. The analysis of operational durability, the typical failures of the cylinder-piston group and other essential parts 
 of 9L28/32A-F MAN B&W engines under different operation modes and loads have been given. During the first overhaul there has been demonstrated the working state of the cylinder-piston group of two engines after 22424 and 22672 h instead of recommended 12000 h for heavy fuel oil. Owing to diagnostic control and monitoring cylinder liner and piston rings assembly, overhauling was made only by condition mode. Maximum working time (40084 h) without cylinder overhaul was reached at suspend power of 75% Pe nom. At a tanker «Georgiy Froier» during 12 years of operation and 64500 working hours only 15pistons were overhauled instead of 48recommended, with changing 39 piston rings instead 194 recommended. In the future, the engines worked up to 
 100 thousand hours without top overhaul, with high resource parameters of the main parts on two engines in the shipping company. The operational problems of the engines with isobaric boost system on ships with a fixed-pitch propeller were identified and considered.

Deformation of acetabular press-fit cups: Influence of design and surgical factors

BackgroundDeformation of acetabular cups when press-fitted into an undersized cavity is inevitable due to the inhomogeneous stiffness of acetabular bone. Thinner cups or screw holes might increase the risk of high cup deformation. The aim of this study was to examine the influence of cup design and liner assembly on the deformation response during cup implantation. MethodsAcetabular cups with different designs were implanted into polyurethane foam models simulating the anatomical situation with nominal press-fits of 1mm and without nominal press-fits (line-to-line). Deformations were determined using a tactile coordinate measuring machine. A 3D laser scanner was used to determine the contact conditions at the cup-cavity interface. Polyethylene and ceramic liners were assembled to the implanted cups and the influence of the insertion on the deformation response evaluated. Fixation strength of the cups was determined by push-out testing. FindingsCup deformation increased with smaller wall thickness (P < 0.037) and screw holes (P < 0.001). Insertion of ceramic liners reduced the deformation (P < 0.001), whereas polyethylene liners adapted to the deformation of the implanted cups (P > 0.999). Thin-walled cups exhibited a higher fixation strength for similar implantation forces (P = 0.011). InterpretationThin-walled cups achieved higher fixation strengths and might be more bone-preserving. However, in combination with screw holes and high press-fit levels, wall thickness should be considered carefully to avoid excessive cup deformations leading to potential complications during liner assembly. Line-to-line insertion of thin-walled cups should be accompanied with a rough surface coating to minimize the loss of fixation strength due to the low press-fit fixation.

Some Promises of Magnetic Implosion of High-Velocity Liners in the ALT-3 Driver

Simulations of the ALT-3 explosive magnetic driver with modifications in its measuring unit and liner assembly are reported. They demonstrate new capabilities of the driver as applied to materials properties studies under ramp and shock compression up to ~80 and ~80 Mbar, respectively.

Simultaneous Drilling, Completions Concept Hopes To Extend Drilling Distances to 30 km

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 178859, “Long-Reach Well Concept,” by Sigmund Stokka, SPE, Eric Cayeux, SPE, David Gardner, SPE, Steinar Kragset, Hans Petter Lohne, SPE, Erlend Randeberg, Hans Joakim Skadsem, and Bjarne Aas, IRIS; Henrik Kyllingstad, Hole in One Producer; Torgeir Larsen, Wintershall; and Arild Saasen, SPE, Det Norske Oljeselskap and University of Stavanger, prepared for the 2016 IADC/SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 1–3 March. The paper has not been peer reviewed. Current extended-reach-drilling (ERD) well technology limits the well lengths to approximately 12 km, with a horizontal departure of approximately 10 km. This paper presents a concept that enables simultaneous drilling and completion, with an aim to extend well reach substantially and with an ultimate objective of constructing 30-km-long production wells. Longer-reach wells can be used to drain remote reserves using existing production facilities and to provide a means to access reservoirs located beneath environmentally sensitive areas. Concept Description The concept introduces a new way of constructing production wells. During drilling, the annulus is closed by packers and the well is drilled to the final target with one hole diameter. A steerable drilling module performs the drilling operation. A dual-wall casing replaces the drillstring and enables the drill cuttings to be transported to surface inside the inner casing. The string does not rotate during drilling but is pulled forward by a multiple-traction system com-posed of traction modules tentatively spaced at 120-m intervals along the drillstring. Tools for well completion, such as sand screens, sensors, and control systems, are integrated into the dual-wall casing. Fig. 1 shows an illustration of the tool string with two dual-traction units spaced with an intermediate-casing section. Dual-traction units are required to maintain zonal isolation at all times and to enable the string to move smoothly and continuously into the ground as drilling progresses. System Description This project investigated two versions of the concept: a casing-drilling system sized for 12¼-in. hole and a liner-drilling version deployed on drillpipe for an 8½-in. hole size. Recently, the project has focused primarily on the liner version. The developed solutions, however, are applicable to both versions. The liner concept provides a liner-drilling solution able to extend the well from a pre-existing production-casing-shoe depth. The liner assembly that can be deployed will be limited by the depth of the production-casing shoe and, thus, can enable the construction of wells up to perhaps 20 km in length. The liner is deployed using standard drillpipe; therefore, conventional rig equipment can be used for the drilling/completion operations. In contrast, the full production-casing-drilling concept can drill deeper wells but will require considerable modifications to topside facilities. The main components of the liner system are a pipe-in-pipe circulation system and multiple hydraulically powered traction units to overcome mechanical friction and provide weight on bit. The liner system is deployed on drillpipe using a running tool that channels the mud supply and cuttings returns in addition to connecting data communication between the surface and bottomhole assemblies (BHAs).

OPERATIONAL EVALUATION OF PISTON-RINGS-CYLINDER LINER ASSEMBLY WEAR IN HIGH POWER MARINE DIESEL ENGINES

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.

The Tribofilm Formation of ZDDP Under Reciprocating Pure Sliding Conditions

The anti-wear and anti-seizure performance and action mechanisms of zinc dithiophosphate (ZDDP) have been investigated under reciprocating pure sliding conditions to simulate piston ring and cylinder liner assembly, using new techniques. The Mini Traction Machine–Space Layer Imaging is a useful method for monitoring tribofilm formation by ZDDPs. However, tests are generally carried out in mixed sliding–rolling conditions and ZDDP film formation in reciprocating pure sliding conditions is rarely investigated. In this paper, the authors describe an investigation of ZDDP film formation in stationary ball on reciprocating disc pure sliding conditions and compare the results to those obtained in unidirectional pure sliding conditions. In unidirectional pure sliding conditions, the worn area on the ball expands with test time. By contrast, in reciprocating pure sliding conditions, tribofilm forms on the stationary ball and no significant damage occurs. In the initial tribofilm formation under reciprocating pure sliding conditions, solid particulate tribofilm with a high concentration of S forms initially in the contact area and subsequently breaks up. During further rubbing, a Zn- and P-rich tribofilm forms on the comminuted sulphur-rich tribofilm and also the area where the initial tribofilm was removed.

Investigation of friction characteristics in segmented piston ring liner assembly of IC engine

Summary The friction at the piston ring cylinder liner assembly (PRLA) is a major contributor in the total friction losses in the I.C. engine. New materials, coatings and high-tech machining processes that previously were considered to be too expensive and therefore only used in complex applications are today becoming more affordable. A significant amount of the total power loss in a modern automotive engine is due to the Friction interaction between the top compression ring and the cylinder liner, especially at the TDC and BDC where boundary lubrication exists. The change in piston speed is accompanied with change the lubrication regime in the cylinder, which results change in friction between the ring and the liner during the entire stroke of the piston. Theoretical modelling of friction force from the various sources of friction will be compared to experimental results for analysing the tribological characteristics. The appropriate sample of piston ring and cylinder liner pair is developed for studying the different tribological parameters on Reciprocating Tribometer. The variable parameters are engine speed, oil viscosity, and load. The experimental results and observations are studied under different operating conditions in speed ranges from 300 rpm to 1500 rpm with constant load of 60 N. It can be seen that as speed increases, the friction force and friction coefficient also decreases.

The Influence of Fuels Quality on Tribological Wear in Slow Speed Diesel Engines

In this article, there are presented problems of tribological wear occurring in slow speed diesel engines elements such as piston – piston rings – cylinder liner assembly and fuel injection pumps caused by use of poor quality fuels. There are defined specific quality standards for bunkered marine residual and distillate fuels with accordance to ISO Standard 8217:2010 and recommended by engine maker’s fuel quality at engine inlet. Moreover, there are characterized common contaminants in this fuels with special attention to the most harmful the residual fuel catalytic particles so-called Cat-Fines, specified the maximum limits and described their influence on engine’s tribological pairs. Furthermore, this paper considers the operational precautions and treatment of poor quality fuels with elaboration of specific procedures to prevent and reduce the influence of Cat-fines to tribological wear in engine elements containing issues of fuel oil storage and distribution on board, fuel oil treatment, usage of poor quality fuels and condition monitoring of engine elements.

Test and Analysis on Assembly Deformation of Diesel Engine Cylinder Liner

The measurement of deformation of one diesel engine water cooling cylinder liner under free condition and assembly load case is carried out by V-INCOMETER testing system. The basic principles of radial deformation for this cylinder liner are obtained through the test data Fourier transformation. And the affect principles of cylinder liner original distort, which results from mechanical machining and heat treatment process, to the cylinder liner assembly deformation are carried out.

The Simulation Research on Assembly Deformation of Internal Combustion Engine Cylinder Liner

For the commonly used wet cylinder liner assembly characteristics and structure of water-cooled internal combustion engine, the influencing factors of wet cylinder liner deformation in the assembly conditions are calculated and analyzed using finite element method. Mainly from the matching stiffness of block-cylinder liner-gasket-cylinder head assembly, the local stiffness of the cylinder head, cylinder head bolt preload and the structure form of cylinder liner, get the influence laws of the various factors on the cylinder liner radial deformation and its each order Fourier series deformation, which provides guidance direction to control the cylinder liner deformation under assembly loading.

Micro-perforated acoustic liner

An example liner assembly includes a backing plate that supports a cellular structure covered by a perforated face sheet including a plurality of openings. Each of the plurality of openings is of a size determined to provide desired acoustic performance.