Engine Piston Ring Research Articles

Numerical calculation and experimental study on friction and lubrication of Stirling engine piston ring

To solve the practical problem of Stirling engine piston ring, numerical model on friction and lubrication were established based on average Reynolds equation theory. Numerical calculation results show: piston rings are in the mixed lubrication state which gas lubrication film and micro-convex body contact existing simultaneously; contact pressure is 2 orders of magnitude less than gas film pressure; contact pressure is approximately linearly related to mean gas pressure. Simulated test rig was built and experimental results show: high-pressure working gas leak to intermediate chamber through piston rings, and the pressure of intermediate chamber drops sharply at lowest pressure of circulation; piston ring wear increases when rotational speed or working pressure increase. The accuracy of numerical model was proved by experimental phenomena and test data.

The Vibration Characteristics of Diesel Engine Cylinder Piston Rings Under Different Wear

In this paper, Through the experimental research on the wear of cylinder liner and piston ring of diesel engine under different forms, The purpose is to study the vibration law of piston ring of cylinder liner of diesel engine under different wear conditions, and obtain the vibration law through vibration signal analysis, which provides theoretical support for the design of diesel engine. The relevant laws are obtained, which provides good technical support for the follow-up design and research. to explore the use of vibration signals to monitor the cylinder piston ring wear state of the feasibility of starting, summed up the vibration signal of diesel engine piston ring and cylinder liner wear contact the specific state, According to the wear state of multiple sets of cylinder liner piston rings and the change trend of each characteristic parameters of vibration signal: As the wear of the piston ring increases, the vibration signal increases and the vibration characteristic parameters increases; The variation trend of each vibration characteristic quantity with the cylinder liner piston ring is basically the same, and it increases with the increase of wear quantity; When the amount of cylinder liner piston ring is large, the gap between them is also large. The increase of clearance causes the change of characteristic parameters greatly, otherwise it is smaller. Therefore, the larger the gap, the more reliable the diagnosis will be the vibration signal analysis cylinder piston ring wear state of the specific program for diesel engine maintenance and provides the basis for maintenance.

Study on Bio-Diesel as Alternate Fuel Used in I.C. Engines

One of the major incentives for expanding the production and use of bio-fuels worldwide is the potential environmental benefit that can be obtained from replacing petroleum fuels with fuels derived from renewable biomass resources. The use of vegetable oil in diesel engines is one of the available alternatives, but its use in existing vehicles usually requires modification of engine or fuel system components. The increased viscosity, low volatility, and poor cold flow properties of vegetable oils lead to severe engine deposits, injector coking, and piston ring sticking. The paper presents a literature review on vegetable oils as alternative bio-fuel for diesel engines.

Simulation of deposits effect on cylinder liner and influence on new and worn compression ring of a turbocharged DI engine

Engineers and engine manufactures have known for years that piston rings account as the main source of the friction in internal combustion engines, as much as seventy-five percent in many cases. Excessive engine wear is also, very often caused by poor vehicle operation, and subsequent momentary poor lubrication.The paper presents a numerical methodology and results regarding the wear and deposition effects on an internal combustion engine piston rings as a result of engine lubrication. The deposits can lead to increment of oil consumption and emissions, reducing engine performance and fuel economy.A 2D CFD approach was implemented in order to investigate the characteristics of the top compression ring deposit formation in a diesel engine. The developed pressures, the friction force and the minimum film thickness have been investigated. The variation of the minimum film thickness for new and worn rings at piston reversals, the insufficient minimum film thickness, the thicker films of the increment of the engine speed appeared at worn ring profile in the middle of each stroke, corresponds to a worst sealing behavior due to deposit, are some of major findings of this work.The deposits investigation and hence the paper importance is crucial in combustion engines operation as well as it can covers both axial turbines and their cooling at preliminary design phase.

Modeling of piston ring wear

A theoretical study of piston ring wear in large two-stroke engines is presented. Piston rings in combustion engines are manufactured with an initially defined shape of the surface contacting the cylinder liner. Further the ring surface working against the cylinder liner is coated with layers of ceramic materials to accommodate the running-in process. Most rings have a nonflat shape (parabolic) when delivered from the ring supplier. After running in which is typically many hours of operation( >1000 h) the ceramic layers are worn and the ring geometry is typically changed significantly by surface wear. It is shown in the present study that the geometry of the worn ring depends on the operation scheme of the engine. Both the load pattern and the order in which the loads are applied influences the final shape of the piston ring surface.

Research on the influence of the lubrication status at the inlet on the lubrication characteristics of engine piston ring

AbstractIn current researches on the lubrication of engine piston ring, some were based on a hypothesis that the piston ring is on a flooded lubrication status. Although some others belong to the starved lubrication analysis, the one‐dimensional model, a certain form of starved lubrication status or simplified manner were used. In this paper, on the basis of the equations about the lubricating oil flow‐rate and control volume, a flow model of lubricating oil in the piston ring‐cylinder liner conjunction is established, and the influence of the situation of supplied lubricating oil film at the piston ring inlet on the two‐dimensional starved lubrication characteristics of piston ring for a four‐stroke engine is studied. The results indicate that the lubrication condition at the piston ring inlet has significant impact on the lubrication characteristics of piston ring. When the supplied lubricating oil at the piston ring inlet increases, the minimum film thickness of piston ring will increase, meanwhile the maximum film pressure, asperity contact force, friction force and power loss will decrease. If the film thickness at the piston ring inlet is smaller, the increase of the supplied film thickness can improve obviously the lubrication characteristics of piston ring.

Examining the role of hexagonal boron nitride nanoparticles as an additive in the lubricating oil and studying its application

Lubricating oil plays an important role in minimizing the friction and wear of many mechanical systems. The additives present in the conventional lubricant are inadequate to reduce the friction and wear of today’s mechanical systems. However, the use of these additives has a significant effect on the environment due to their fast chemical degradation. In recent years, nanoparticle-based lubricant has attracted great attention due to their friction reduction behavior. Therefore, it is of great importance to examine the role of nanoparticle addition in the conventional lubricant and its influence on the tribological characteristics of the mechanical systems. Hence, this research work focused on the formulation of hexagonal boron nitride nanoparticle-based nanofluids and its effect on the tribological characteristics of cylinder liner and piston rings of a realistic diesel engine. The different concentrations of hBN nanoparticle-based nanofluids were formulated and characterized using the ultraviolet–visible spectroscopy and the thermal gravimetric analysis. The results of the experimental analysis showed that hBN nanoparticles as an additive in the lubricating oil exhibited better anti-wear and friction reduction behavior than the conventional base oil 20W40.

Grinding process applied to workpieces with different geometries interrupted using CBN wheel

Although the fact that the interrupted cutting process is widely employed in traditional machining operations such as turning of crankshafts, engine piston ring, and helical tool sharpening, only a few number of studies in the literature approach this process. This study aims to evaluate the performance of the interrupted grinding process of workpieces with a different number of grooves (2, 6, and 12) in CBN grinding and to contribute to further findings about the integrity of interrupted surfaces and groove flanks after grinding, analyzing surface roughness and roundness deviation of workpieces after grinding process. The diametric wheel wear and grinding power were also recorded and analyzed. The performance of the interrupted grinding process was compared with the continuous grinding process, i.e., for workpieces without grooves. The AISI 4340 steel workpieces were tested under the application of flood lubri-cooling method at different feed rates (0.25, 0.50, and 0.75 mm/min). In conclusion, higher feed rate increased the surface roughness from 0.12 to 0.35 μm for continuous grinding process, respectively at 0.25 and 075 mm/min. The interrupted grinding led to increase of surface roughness Ra values from 0.19 to 0.43 μm (respectively 58.3% and 22.9% higher than continuous) for 2 grooves, 0.31 to 0.59 μm (respectively 158.3% and 68.6% higher than continuous) for 6 grooves and 0.54 to 0.93 μm (respectively 341.7% and 165.7% higher than continuous) for 12 grooves, respectively at 0.25 and 0.75 mm/min. As presented for surface roughness values, the increase of groove number resulted in higher values of roundness deviation, diametric wheel wear due to mechanical shocks caused by couplings and uncouplings of the grinding wheel. It was evidenced by SEM images of groove flanks and macro-fracture mode of abrasive grains. No microstructural damage was caused by thermal or mechanical irrespective of the experimental conditions investigated.

Thermal and static analysis of engine piston rings

The piston is the most important component of internal combustion engines. The piston ring contains a ring pack and cylinder wall. The piston ring is the moving component and it is composed of aluminium matrix composites. The aim of the work is to determine the structural and thermal stress distribution of piston rings using CATIA and ANSYS. Combustion engine pistons transform heat energy into mechanical energy by expanding gases. The thermal and structural analyses were done on the piston rings model using the properties of aluminium matrix composites (aluminium A2024 alloy and fly ash).

Review of tribological behavior of graphene coatings on piston rings in engines

Purpose This study aims to find out friction and wear characteristics of graphene and graphene coating deposited by the Chemical Vapor Deposition (CVD) process on Honda GX270 engine (nodular cast iron) piston rings experimentally investigated under boundary lubricated conditions. Design/methodology/approach This study consists of two stages: tribotest and engine tests. First test was conducted through a reciprocating tribotest machine and second test was conducted through an engine bench with a duration of 75h. Engine piston ring was coated with graphene by two different methods: transfer method and direct CVD method. Findings Graphene has been demonstrated to be a potential and promising candidate for wear- and scratch-resistant coating because it is the thinnest, lightest and strongest known nanomaterial. In this case, the ability of a mono-layer graphene film to withstand high pressure differences (6 atm) indicates its mechanical robustness. It can effectively prevent or reduce mechanical failure by strengthening and toughening the loaded surface as well as by transferring the stress throughout the structure. The positive tribological outcomes of the graphene reinforced material under various dynamic loads revealed the potential of graphene-based coatings in macro - and micro-tribology. Originality/value This study fulfils an identified need to study for automotive industry a coating which is wear and scratch resistant.

Wear Evaluation of Engine Piston Rings Coated With Dual Layer Hard and Soft Coatings

The main objective of this investigation is the evaluation of the performance of hard diamond-like-carbon (DLC) or tungsten carbide (WC) and soft (epoxy composite) dual-coatings on the internal combustion (IC) engine piston rings as a protective coating to reduce their wear. The rings were coated with DLC or WC by physical vapor deposition (PVD) method and then soft polymeric composite coating (epoxy/graphene/base oil SN150) was applied on the hard coating. The tribological tests of the dual-coated piston rings were conducted for 3.6 × 105 cycles at 1500 rpm engine speed and 50% rated load of a diesel engine in order to evaluate the wear performance of the piston rings. Scuffing of cylinder liner and piston rings interface was prevented by the application of polymer composites over the hard-coated rings. DLC hard and soft polymer composite dual coating over the top piston ring was found to have the lowest wear rate 1.69 × 10−12 mm3/N·m compared with the wear rate of dual coatings on the middle and lower rings.

Design, Optimization and Analysis of a 4-stroke Diesel Engine Piston and Piston rings using Different Materials

Modern Automobiles expect a high performance from its engines, which in turn places its requirements on the piston and cylinder components. Hence the piston has to deal with harsher, and tougher thermal and mechanical conditions. It has to undergo higher operating temperatures and pressures as well as higher speeds and at the same time keeping a check on the emissions. Pistons play a key role in increasing engine efficiency by reducing weight and frictional losses. This has made it essential to devise and search unique and creative concepts and materials for Pistons repeatedly, which offers what the engine demands.In this work Aluminium Alloy-4032 has been selected as the piston material of a 4-Stroke Diesel Engine and the piston rings are made of grey cast iron and alloy steel. Piston is designed by analytical methods taking both thermal and structural effects into consideration, then modelled on CATIA V5 and the analysis of structural deformation due to thermal stresses has been done using Finite Element Analysis of Steady State Thermal and its effect on static structure using Analysis software ANSYS.

Numerical analysis of gas flow through the labyrinth seal of piston rings of an automotive IC engine

In the paper a model of transient gas flows through the labyrinth seal: piston-rings-cylinder (PRC) has been presented. The results of calculations for a ring pack of three piston rings operating on a cylinder liner of a spark ignition internal combustion engine have been shown. The analysis of the gas dynamics and a parametric study considering this phenomenon has been carried out. It allowed evaluating the influence of the most important parameters of this sealing on the gas pressure acting on the rings and blow-by to the crankcase. The simulation results show the necessity of taking into account the following parameters: uneven wear of cylinder liner and its thermal and mechanical deformation, thermal deformation of piston rings, heat transfer between the flowing gas and the labyrinth walls, dynamics of axial ring displacements in piston grooves.

A tribological analysis on stuffing box-piston rod system of low-speed marine diesel engines

The stuffing box-piston rod system is widely used in the low-speed marine diesel engines to scrape oil and ensure sealing. Its friction power loss and wear rate are great, but the studies about the system are very limited. In this study, based on the special structure and working conditions of the stuffing box, the analytical model for the tribological properties of the stuffing box-piston rod system is developed considering the oil starvation and relative ring location effects. The minimum oil film thickness, friction, oil transportation, and asperity contact are calculated for the stuffing box. The analysis results show that compared with the fully flooded lubrication, the minimum oil film thicknesses of the rings reduce significantly in the middle of the strokes under the starved lubrication condition, but the friction losses of the rings are influenced by the comprehensive effects of the oil film thickness reduction and lubricating area reduction under the starved lubrication condition, which is related to the specific profiles of the rings. In addition, compared with the engine piston ring pack, the relative ring location effect is more obvious in the stuffing box ring pack because there are more rings and the ring intervals are larger. The relative ring location effect makes the minimum oil film thicknesses, friction forces, and asperity contacts of the rings have oscillations after bottom dead center and top dead center.

Design, Optimization and Analysis of a 4-stroke Diesel Engine Piston and Piston rings using Different Materials

Modern Automobiles expect a high performance from its engines, which in turn places its requirements on the piston and cylinder components. Hence the piston has to deal with harsher, and tougher thermal and mechanical conditions. It has to undergo higher operating temperatures and pressures as well as higher speeds and at the same time keeping a check on the emissions. Pistons play a key role in increasing engine efficiency by reducing weight and frictional losses. This has made it essential to devise and search unique and creative concepts and materials for Pistons repeatedly, which offers what the engine demands. In this work Aluminium Alloy-4032 has been selected as the piston material of a 4-Stroke Diesel Engine and the piston rings are made of grey cast iron and alloy steel. Piston is designed by analytical methods taking both thermal and structural effects into consideration, then modelled on CATIA V5 and the analysis of structural deformation due to thermal stresses has been done using Finite Element Analysis of Steady State Thermal and its effect on static structure using Analysis software ANSYS

Interfacial Microstructure Evolution Due to Strain Path Changes in Sliding Contacts.

We performed large-scale molecular dynamics (MD) simulations to study the transient softening stage that has been observed experimentally in sliding interfaces subject to strain path changes. The occurrence of this effect can be of crucial importance for the energy efficiency and wear resistance of systems that experience changes in the sliding direction, such as bearings or gears in wind parks, piston rings in combustion engines, or wheel-rail contacts for portal cranes. We therefore modeled the sliding of a rough counterbody against two polycrystalline substrates of face-centered cubic (fcc) copper and body-centered cubic (bcc) iron with initial near-surface grain sizes of 40 nm. The microstructural development of these substrates was monitored and quantified as a function of time, depth, and applied pressure during unidirectional sliding for 7 ns. The results were then compared to the case of sliding in one direction for 5 ns and reversing the sliding direction for an additional 2 ns. We observed the generation of partial dislocations, grain refinement, and rotation as well as twinning (for fcc) in the near-surface region. All microstructures were increasingly affected by these processes when maintaining the sliding direction but recovered to a great extent upon sliding reversal up to applied pressures of 0.4 GPa in the case of fcc Cu and 1.5 GPa for bcc Fe. We discuss the applicability and limits of our polycrystalline MD model for reproducing well-known bulk phenomena such as the Bauschinger effect in interfacial processes.

Contribution to cylindrical grinding of interrupted surfaces of hardened steel with medium grit wheel

Grinding is generally the first choice to provide combination of both superior surface finish and closer dimensional tolerances in a machined component. This process can be employed in manufacturing of continuous and interrupted surfaces. Crankshafts and engine piston rings are examples of ground precision mechanical components having interrupted surfaces. However, the specific literature about grinding of interrupted surfaces is still scarce. In this context, aiming to further contribute to the understanding of the behavior of surface integrity of interrupted surfaces during grinding, this paper presents an experimental investigation of interrupted surfaces ground with white aluminum oxide grinding wheel. Discs of AISI 4340 hardened steel with different number of grooves (2, 6, and 12) on the external surface were tested. Experiments with discs without interrupted surface were also carried out for comparisons. In addition to the number of grooves, three values of infeed rate (0.25, 0.50, and 0.75 mm/min) were used as input parameters. The output parameters investigated were the geometric errors (surface roughness and roundness) of the workpiece material as well as the diametric wheel wear. Analysis of variance (ANOVA) test was performed to verify any statistical difference among the output variables. Results showed that both surface finish and roundness of workpieces with interrupted surfaces were higher than those obtained for continuous surface. These parameters also increased with infeed rate up to 0.50 mm/min, whereas the grinding wheel wear was more sensitive to number of grooves and infeed rate. No thermal damages were observed on the machined workpieces under the conditions investigated.

A method for reliability improvement in air brake system of compressed air cars

Abstract At the present moment in the Russian Federation, there is a difficult situation about manufacturing piston rings for internal combustion engines and compressors. The main reason for a decrease in the manufacturing rate is the fact that Russian manufacturers cannot keep up in the economic competition with world’s top manufacturers, such as Federal Mogul (USA), Prima (Poland) and other brands that are not as widely known. It is noteworthy that the world leaders in the industry promote their product in the Russian market with the focus on supplying parts for new piston engines. That is why there is shortage in the spare parts market, which significantly decreases the repairs capabilities. At the same time, it should be noted that Russia has such manufacturers who have technological capabilities and skilled staff to manufacture piston rings able to meet competition. In this article we propose a method to increase the reliability of the pneumatic braking system in a vehicle with a pneumatic compressor by using composite compression rings having improved operational characteristics, low production cost and good adaptability to manufacture.

The anti-wear efficiency of boron succinimide on engine cylinder liner and piston ring surfaces

Anti-wear additives are important components of the lubricating oils which protect the sliding surfaces from wear. Researches on developing the non-phosphorus catalysis-friendly anti-wear additive still continue due to government’s regulations. One way to provide non-phosphorus anti-wear additive is boron and sulfur addition to succinimides. In this study, boron succinimide used as an anti-wear additive is compared with ZDDPs in a real engine environment by the engine bench tests. Anti-wear performances were evaluated by microscopic and spectroscopic surface analyses on engine cylinder liner and piston rings after 100-h engine running periods for each anti-wear additive. SEM/EDX and XPS analyses were used to evaluate the tribochemical analyses of tribofilms. SEM and AFM were used to evaluate wear mechanisms on cylinder liner and piston ring surfaces. Results showed that boron succinimide can be an alternative anti-wear additive of ZDDPs from the perspective of anti-wear efficiency.

Performance analysis and condition monitoring of ICE piston-ring based on combustion and thermal characteristics

Optimal sealing performance of the piston ring is an important condition for the internal combustion engines (ICE) to maintain combustion efficient. The objective of this paper is focused specifically on the effects of piston ring end gap and axial ring-groove abnormal clearance on the combustion and thermal characteristics such as instantaneous pressure distribution, temperature, combustion heat release rate (HRR) and predicted of combustion gas flow rate (blow-by) approaches were investigated. A comparative study was done on combustion characteristics of the healthy and faulty engine piston ring. The combustion and thermal data was analyzed to use engine fault diagnostic technique. The diagnostic technique is applied for each test case to estimate the faults ratiometric indexes (FRI) and to evaluate the piston ring condition. The FRI shows significantly increased with the increased of piston ring end gap and this trend was more obvious at the increased piston groove clearance. The results obtained indicate that the proposed diagnostic methodology can identify the piston ring condition monitoring according to the thermal and combustion characteristics effectively.