Valve Wear Research Articles

Effect of coatings on the tribological performance of engine valve train: A review

Coatings play a crucial role in engine valve train components, reducing friction and wear to enhance engine efficiency and longevity. Common coatings in internal combustion engines include Diamond-Like Carbon (DLC) and Hard coatings, all of which improve tribological performance. These coatings are vital for valve trains, which face high stress and temperature variations. Deposition techniques like Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), and Plasma-Assisted Chemical Vapor Deposition (PACVD) influence coating performance. DLC coatings, often metalloid-doped, are noted for their low friction and high hardness. Hard coatings excel in wear resistance and friction reduction. This review brings together experimental findings on tribological coatings for engine valve train components, focusing on materials, deposition methods, testing conditions, and performance metrics. It highlights the best coatings for reducing wear and friction, ultimately enhancing the performance of internal combustion engines. Among the coatings evaluated, Chromium Nitride with Tungsten Carbide/Carbon (CrN + WC/C) stood out. This coating significantly reduced friction torque at low to moderate rotational speeds (with reductions of 20%–30% at 800 rpm and 1400 rpm) and maintained this reduction at high speeds (30% reduction at 2000 rpm). Additionally, under high load conditions, the CrN + WC/C coating achieved a remarkable 75% reduction in mean friction torque (reducing it from 4 to 1 Nm at both 800 and 2000 rpm). These tests were conducted using SAE 10W-30 oil at 80°C. The consistent performance of CrN + WC/C across varied conditions makes it the superior choice. CrN + WC/C coatings optimize the efficiency and longevity of valve train components by reducing friction, wear, and maintenance needs, significantly enhancing engine system reliability.

Histological Findings in Infective Endocarditis-A Retrospective Cohort Study Conducted at "Dr. Carol Davila" Central Military Emergency University Hospital in Bucharest.

Histological findings of infective endocarditis (IEs) in mechanical valves present a complex diagnostic challenge owing to the lack of a precise definition. This ambiguity is further complicated by the natural degenerative processes that occur in the mechanical valves over time. Consequently, pathologists and clinicians face significant difficulties in distinguishing between genuine infective processes and the normal wear and tear of mechanical valves. This retrospective cohort study was conducted between January 2017 and January 2024 and examined tissue samples from 93 patients who underwent a surgical removal of mechanical heart valves, with 41 cases suspected of infective endocarditis and 52 cases of non-IE. The researchers aimed to establish more precise histological criteria for distinguishing between these two conditions, focusing on two key features: vegetations and inflammatory patterns. IE in patients with prosthetic heart valves presents distinct histological features that aid in the diagnosis and differentiation of non-infective complications. Hallmark characteristics include vegetation and inflammatory infiltrates with neutrophils. Valve tissue specimens from patients whose mechanical valves were removed because of non-infectious complications showed a different histological profile. Inflammatory infiltrates were observed in approximately 26% of these cases; however, they were primarily composed of macrophages and lymphocytes rather than neutrophils. By emphasizing neutrophil-rich inflammation as a key indicator, clinicians and pathologists could more effectively distinguish between true infective endocarditis and non-IE that can occur in the mechanical valves. This distinction is crucial for appropriate patient management as the treatment strategies for infective and non-infective valve conditions differ significantly.

Research on Fault Diagnosis Method of Reciprocating Compressor Based on RSSD and Optimized Parameter RCMDE

As for the fault diagnosis process of a reciprocating compressor, vibration signals are often non-stationary, nonlinear, and multi-coupled, which makes it difficult to conduct effective fault information extraction. In this paper, a method based on optimized resonance-based sparse signal decomposition (RSSD) and refined composite multiscale dispersion entropy (RCMDE) is proposed. The quality factors in RSSD are optimized by atom search optimization (ASO) primarily, then the optimal quality factors are applied to the RSSD of reciprocating compressor fault signals. The noise interference in the original vibration signal can be effectively distinguished from the low resonance component after decomposition. The genetic algorithm (GA) is employed to optimize the core parameters of RCMDE. Finally, the RCMDE of the low-resonance component is extracted as the eigenvalue for pattern recognition. The experimental study illustrates that the spring failure, valve wear, and normal valve conditions of reciprocating compressors can be effectively distinguished by the proposed method.

Analysis of erosion and sealing characteristics of V-regulating ball valves for coal chemical industry

Purpose This study aims to research the erosion wear characteristics and sealing performance of V-regulating ball valve in coal chemical process pipelines, which provides a theoretical reference for improving its antiwear and sealing performance. Design/methodology/approach Taking the V-regulating ball valve as the research object, based on the computational fluid dynamics and the theory of erosion wear, the authors studied its erosion characteristics under different medium parameters and analyzed the sealing performance under the heat-fluid–solid coupling working condition. Findings The erosion wear mechanism of the valve sealing surface is the simultaneous action of cutting and deformation. When the medium flow velocity, particle mass flow rate and particle size increase, the maximum erosion rate and average erosion rate in the V-regulating valve increase. The inner diameter Mises contact stress of the sealing surface is symmetrically distributed in a “wing shape,” and the contact stress of the outer diameter is distributed in a “butterfly shape.” Due to the superposition of thermal stress and pressure stress in the contact transition zone to produce a significant stress concentration. Practical implications The findings will provide a theoretical basis for improving the erosion resistance and sealing performance of V-regulating ball valve in coal chemical industry. Social implications V-type regulating ball valve is widely favored by coal chemical enterprises and petrochemical enterprises because of its wide adjustment ratio and good erosion resistance. Originality/value The V-regulating ball valve wear mechanism for cutting and deformation simultaneously, and its wear rate is positively correlated with the medium flow rate, particle mass flow rate and particle size. After the valve is opened, there is a significant stress concentration occurs in the contact transition zone due to the superposition of thermal stress and compressive stress. The findings will provide a theoretical basis for improving the erosion resistance and sealing performance of V-regulating ball valve in coal chemical industry. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0205/

Effect of material anisotropy on the first-order vibration of piezoelectric oscillators in circular plate configurations

Valveless piezoelectric pumps are widely used in microfluidic actuation because of their simple structure, ease of integration, absence of electromagnetic interference, minimal valve wear, and absence of frequency–response lag issues. These pumps primarily rely on chamber volume changes, causing most piezoelectric oscillators to operate in the first-order vibration mode. However, recent studies on valveless piezoelectric pumps have observed that many pumps exhibit two flow peaks at similar operating frequencies; the underlying mechanism behind this anomaly remains underexplored. In this study, we investigated the impact of substrate metal on the first-order vibrations of piezoelectric oscillators. By conducting tensile tests on rolled pure copper sheets, we measured Poisson's ratio and the elastic modulus in both the parallel and perpendicular rolling directions. Subsequently, we derived the natural frequencies on the plane. Experimental verification of the theoretical predictions was achieved through amplitude experiments conducted on piezoelectric oscillators in air. The dual-peak flow phenomenon was demonstrated to be solely related to the substrate metal of the piezoelectric oscillator. This is attributed to the presence of two first-order vibration natural frequencies on the plane of the substrate metal, resulting in the generation of two amplitude peaks and consequently the appearance of two flow peaks.

Wear Mechanics of the Female Locust Digging Valves: The “Good Enough” Principle

AbstractAdult female desert locusts (Schistocerca gregaria) dig underground to lay their eggs, ensuring optimal conditions for successful hatching. Digging is performed using the two pairs of oviposition valves at the tip of the female's abdomen. These valves are subjected to considerable shear forces during the repeated digging cycles, potentially leading to wear over time. The resilience of the valves is investigated by analyzing the relationship between digging experience and valve damage and wear throughout the female locust's life. The findings reveal the ability of the valves to withstand the significant shear forces encountered during digging. Despite this resilience, however, perceptible limitations in the valves’ mechanical durability against wear are observed. Toward the end of the female locust's life, the valves show substantial signs of wear, indicating effective performance but with limited longevity, i.e., a designated life span that enables successful oviposition for ca. four oviposition cycles. A comparison of the valve material with that of the animals’ mandibles, which are used continuously throughout their life and show remarkable wear‐resistance, further highlights the evolutionary adaptation of the valve materials to their specific function, suggesting a trade‐off between energetic investment and the sufficient, or “good‐enough”, performance that is required for survival.

Prediction of packing performance of pneumatic control valve based on stem mechanism model and VMD-SSA-LSTM

Abstract Packing performance is one of the most important parts affecting the control operation of pneumatic control valves. In order to avoid the failure caused by packing wear and aging of pneumatic control valves after long-term use, this paper constructs a valve stem mechanism model and combines the advantage of deep learning to predict the packing performance of pneumatic control valves based on Long Short-term Memory (LSTM) and Variable Mode Decomposition (VMD) and Sparrow Search Algorithm (SSA). Firstly, the historical data of the actuator is calculated based on the mechanism model of the valve stem. The time-friction force obtained by the calculation is the parameter set. After the parameter set is subject to the variational mode decomposition, the parameter set is imported into the SSA-LSTM prediction model for prediction, and the prediction data is obtained.

Tribological Behavior Analysis of Valve Plate Pair Materials in Aircraft Piston Pumps and Friction Coefficient Prediction Using Machine Learning

To address the problem of tribological failure in an aircraft piston pump valve plate pair, the friction and wear properties of the valve plate pair materials (W9Mo3Cr4V-HAl61-4-3-1) of an axial piston pump at a certain speed and load were studied using a disc-ring tester under lubrication with No. 15 aviation hydraulic oil. The results show that the friction coefficient (COF) fluctuated in the range of 0.019~0.120 when the load (L) increased from 30 N to 120 N, and the speed increased from 100 r/min to 500 r/min. With the increase in the rotational speed, the COF of the valve plate pair decreased first and then increased. When the rotation speed (V) was 300 r/min, the relative COF was the smallest. Under L lower than 60 N, abrasive wear was the main wear mechanism. Under L higher than 90 N, the main wear mechanism was adhesive wear but mild oxidation wear also occurred. In addition, based on the V, L, radius (R), and test duration (T), which affected COF, the random forest regression (RFR) algorithm, the bagging regression (BR) algorithm, and the extra trees regression (ETR) algorithm were used as machine learning methods to predict the COF of the valve plate pair. Mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2) were used to evaluate its performance, with the results showing that the ETR prediction model was the best method for predicting COF. The results of the machine learning also showed that the contributions of V, L, R, and T were 43.56%, 36.76%, 13.13%, and 6.55%, respectively, indicating that V had the greatest influence on the COF of the W9Mo3Cr4V/HAl61-4-3-1 friction pair. This study is expected to provide support for the rapid development of new valve plate pair materials.

A Feature Extraction Method for Prognostic Health Assessment of Gas Compressor Valves

Abstract This paper presents features derived from the pressure-volume (PV) diagram that is useful in estimating different valve faults in reciprocating compressors with a strong potential of remaining useful life prediction. The PV diagram is expected to deviate depending on valve wear conditions. The valve degradation types explored in this work are leakage, seat wear, and spring fatigue in the suction and discharge assemblies of a Dresser-Rand ESH-1 compressor commonly used in the petrochemical industry. The proposed method estimates the polytropic exponent on the compression and expansion phase as well as the discharge and suction valve loss power and uses them as features for a quadratic discriminant analysis. The features are created through in-cylinder pressure, suction pressure, discharge pressure, and crank angle measurements collected on a single-stage, dual-acting compressor operating on air with wear precisely machined and seeded into the poppets of the inlet and outlet valves. A very high classification accuracy is achieved in distinguishing the wear types, severity, and location with strong prognostic trends.

DEVELOPMENT OF DOWNHOLE PUMP VALVE ASSEMBLY

The purpose of the work is modernization of the valve, in order to increase reliability, wear resistance, increase the pump flow and reduce the load on the rod string, as well as improve durability. The sucker rod pump is one of the most popular and extensively utilized artificial lift systems. It is a frequently chosen option for lifting oil because of its fundamental simplicity, low operating costs, and adaptability in power supply. In the long run of oil production history, sucker-rod pumping was the first option—and frequently the only option—when artificial lift was required. For this reason, the oldest and most popular method of producing oil wells worldwide is sucker-rod pumping. Since the steel used to make rods has limited strength, sucker-rod pumping is typically thought of as a way to raise moderate to low liquid production rates from shallow to medium well depths due to depth restrictions. Since the correct working of the standing and traveling valves is largely responsible for an efficient pumping operation, valves are regarded as the heart of the sucker-rod pump. The extremely high differential pressures across the valve during pumping necessitate a highly dependable sealing action between the ball and the seat. Small initial flaws in the sealing surfaces or subsequent corrosion- or abrasion-related problems result in greater liquid slipping and a quick decline in valve function because of fluid cutting. Subsurface pumps using traditional ball-and-seat valves suffer a number of basic operational issues: • Because of the greatly high number of pumping cycles per day, the sealing surfaces may sustain significant damage from the frequent collision of the two parts against one another. • In deviated wells, valve wear is uneven and can cause premature failure. • Typical cage constructions, meant to limit impact damage, typically restrict the flow area available through the valve and can be the source of pumping inefficiencies due to low fillage of the pump barrel. Keywords: sucker rod pumps, downhole pump, traveling valve, standing valve, valve assembly.

Predictive maintenance feasibility assessment based on nonreturn valve wear of injection molding machines

Abstract Predictive maintenance techniques are increasingly important in Industry 4.0; they can be applied to nonreturn valves to mitigate waste from improper replacement. To improve such predictive maintenance, this study used four nonreturn valves with different outer diameters to investigate the effects of wear on process variables and product quality under different process parameters. The results indicated that melt temperature (process parameter) had the most substantial influence on the amount of melt backflow. The process variables are the screw position at the end of the packing stage, the slope of the screw position during the packing stage, and peak pressure. The study investigated the influence of nonreturn valve wear on the entire molding process over different periods. The findings can be extended to prediction models for developing process windows and realizing the predictive maintenance of nonreturn valves in injection molding machines.

Numerical study on sealing performance after wear of plug valve during opening–closing process

The failure of the plug valve seal may result in dangerous accidents in the production and transportation process of petroleum and chemical products. In the paper at hand, the operating life of the plug valve is studied in the opening–closing process. The adhesion wear between the sealing surface of the plug valve is numerically studied in micro-scale, and the contact force between the sealing surface is balanced with the internal flow field of the plug valve and the deformation force between the set screw and the spool. The internal flow field of the plug valve in opening–closing process is calculated by finite element method. The deformation coupling model between the set screw and the spool is built to analyze the structure and the mechanics of the plug valve. Then, a leakage identification algorithm based on auto-correlation function is implemented for analyzing contact stress of the plug valve's sealing surfaces after wear. Finally, taking plug valve F-2 ISO-STANDARD as an example, the force of turbulent flow field on the spool is calculated during the closing process. Results show, that while the maximum contact stress increases, the pressure decreases, and the displacement trajectory of spool increases. The operating life decreases by increasing the roughness of the spool sealing surface. The model proposed provides a new practical method to evaluate the operating life of the plug valve, which is a good guidance for the design of the valve.

Exhaust Valve Leakage Analysis on Main Engine at KM. Tonasa Lines XV

The exhaust valve is one of the components on the main engine that functions to close and open the flow of exhaust gas from the combustion chamber or liner, both in four-stroke and two-stroke diesel engines. The research was carried out for ±10 months on the Tonasa Line XV ship. The purpose of this study was to determine the cause of the exhaust valve leak. Primary data were obtained directly through interviews with related parties. Secondary data is obtained from data collection institutions and published to the data user community, in this study in the form of journals in e-journals. The results obtained from research identification show that first: the occurrence of spindle and seat valve wear due to a lack of maintenance systems, second: excess working hours of exhaust valves, third: clogged cooling water system. The identification of the research found that the cause of the exhaust valve leak was due to worn spindle and seat valves, excess working hours and blockage of the cooling water path. The ways that can be done to avoid damage are by grinding the spindle and seat valve, maintenance according to working hours, and cleaning the cooling water.

APPLICATION OF HVOF TECHNOLOGY FOR WC-BASED WEAR-RESISTANT COATINGS – AN OVERVIEW

The article presents the main problems of wear and service life of slide gate valves for trunk pipeline transport of oil and gas industry. One of the possible ways to solve these problems is the application of a thin layer of wear-resistant and corrosion-resistant coatings. Due to the ever-increasing cost of materials, as well as the increased requirements for materials, coating methods have recently become increasingly important. Among the gas-thermal coating methods, the High Velocity Oxygen-Fuel Spray (HVOF) technology is a new and rapidly developing technology that produces high density coatings with porosity less than 1%, with improved hardness and adhesion as well as improved erosion, corrosion and wear resistance properties. This overview article provides a comparative review of the characteristics of carbide coatings produced using different spraying technologies.

Event-driven demand response control of air-conditioning to enable grid-responsive buildings

Fast demand response capability of a grid-responsive building is of particularly high value to meet urgent power balance needs of power grids. In this study, an event-driven control strategy is proposed to effectively unlock building energy flexibility for fast demand response using building air-conditioning systems. The proposed control strategy can properly distribute the chilled water among different zones in a building to allow uniform thermal comfort compromise. Validation tests are conducted and the results show that the limited cooling supply can be distributed properly and the same indoor air temperature profiles can be achieved eventually among the indoor spaces. The power demand of the chiller plant is reduced by 170 kW (5%) by adopting the proposed event-driven control, while achieving the same comfort compromise as existing time-driven control. The average accumulated valve travel distance is also reduced by 54.6%, reducing the wear and tear of the AHU valves significantly.

COMPUTATIONAL MODELING OF EROSION WEAR OF THE FISHER V500 CONTROL VALVE OF THE SLURRY SUPPLY LINE OF THE CATALYTIC CRACKING FACILITY OF OIL RESIDUES

Erosion of the internal surfaces of pipelines and shut-off valves used in oil production is a very dangerous phenomenon. It occurs as a result of the impact on the metal of mechanical impurities contained in the working environment. Erosion often occurs together with corrosion. The type of destruction under the influence of mechanical impurities is determined by the fluid flow rate, and the intensity and rate of erosion depends on the concentration and composition of mechanical impurities. Solving the problem of effectively determining the degree of adverse environmental impact depending on various parameters requires the development of new approaches, such as modeling. Modeling of hydrodynamics to determine critical flow rates and calculation of expected zones and erosion rates is due to the importance of solving the problem of anti-erosion protection. In this paper, CFD modeling of hydrodynamics and erosive wear of the control valve of the suspension line of the catalytic cracking unit is performed in the ANSYS Fluent software package. The flow velocities are calculated, and the areas affected by critical velocities at which corrosion erosion occurs are also shown. The effect of density and content of mechanical impurities on the erosion rate is shown.

CFD-Based Physical Failure Modeling of Direct-Drive Electro-Hydraulic Servo Valve Spool and Sleeve.

Direct-drive electro-hydraulic servo valves are used extensively in aerospace, military and control applications, but little research has been conducted on their service life and physical failure wear. Based on computational fluid dynamics, the main failure forms of direct-drive electro-hydraulic servo valves are explored using their continuous phase flow and discrete phase motion characteristics, and then combined with the theory of erosion for calculation. A mathematical model of the direct-drive electro-hydraulic servo valve is established by using Solidworks software, and then imported into Fluent simulation software to establish its physical failure model and carry out simulation. Finally, the physical failure form of the direct drive electro-hydraulic servo valve is verified by the simulation results, and the performance degradation law is summarized. The results show that temperature, differential pressure, solid particle diameter and concentration, and opening degree all have an impact on the erosion and wear of direct-drive electro-hydraulic servo valves, in which differential pressure and solid particle diameter have a relatively large impact, and the servo valve must avoid working in the range of high differential pressure and solid particle diameter of 20–40 um as far as possible. This also provides further theoretical support and experimental guidance for the industrial application and life prediction of electro-hydraulic servo valves.

Performance Comparison of Control Strategies for Plant-Wide Produced Water Treatment

Offshore produced water treatment (PWT) accounts for cleaning the largest waste stream in the offshore oil and gas industry. If this separation process is not properly executed, large amounts of oil are often directly discharged into the ocean. This work extends two grey-box models of a three-phase gravity separator and a deoiling hydrocyclone, and combines them into a single plant-wide model for testing PWT control solutions in a typical process configuration. In simulations, three known control solutions—proportional-integral-derivative (PID) control, H∞ control, and model predictive control (MPC)—are compared on the combined model to evaluate the separation performance. The results of the simulations clearly show what performance metrics each controller excels at, such as valve wear, oil discharge, oil-in-water (OiW) concentration variance, and constraint violations. The work incentivizes future control to be based on operational policy, such as defining boundary constraints and weights on oil discharge, rather than maintaining conventional intermediate performance metrics, such as water level in the separation and pressure drop ratio (PDR) over the hydrocyclone.

Application based comparison of statistical versus deep learning approaches to reciprocating compressor valve condition monitoring

This paper presents a vibration-based condition monitoring approach for early assessment of valve wear in an industrial reciprocating compressor. Valve seat wear is a common fault mode that is caused by repeated impact and accelerated by chatter. Seeded faults consistent with valve seat wear are installed on the head-side discharge valves of a Dresser-Rand ESH-1 industrial reciprocating compressor. Due to the cyclostationary nature of these units a time-frequency analysis is employed where targeted crank angle positions can isolate externally mounted, non-invasive, vibration measurements. A region-of-interest (ROI) is then extracted from the time-frequency analysis and used to train a suitably sized convolutional neural network (CNN). The proposed deep learning method is then compared against a similarly trained discriminant classifier using the same ROIs where features are extracted using texture and shape image statistics. Both methods achieve > 90% success with the CNN classification strategy nearing a perfect result.

The development of a dependent mathematical model of dielectric properties of an engine oil to the concentration of soot formation

The frequency of engine oil replacement reaches 150 thousand km for modern trucks, which increases the load on the lubrication system, leads to an increase in the level of contamination and to a greater level of oil degradation. The accumulation of dirt in the oil and, above all, soot leads accelerated wear of bearings, valves and camshafts, and increases the rate of formation of sludge and deposits on the piston rings. All this significantly reduces the engine life. The purpose of the work is to estimate the soot concentration in engine oil by its dielectric parameters measured by the waveguide method. To study the dependence of the dielectric parameters of engine oil on the soot concentration, the transmission line method was chosen and an installation was created that allows measuring the signal amplitude in a given frequency range. Tests performed on various engine oils at soot concentrations in the oil from 0 to 1.06% allowed us to identify the most optimal frequency regions where high sensitivity of the method is achieved. The nature of the change in the dielectric constant of engine oil with an increase in the concentration of soot in it is established. Diagnostic indicators such as the frequency of peak peaks and the signal amplitude at the optimal frequency are identified. Mathematical models of the dependence of the peaks amplitude and frequency on the soot concentration in engine oils are constructed.