Cast Iron Liners Research Articles

Usage of the Cast Iron Cylindrical Liner in an Automobile Engine Block

This study addresses the issues related to the quality of the connection between cast iron liners and inserts in a pressure die-cast automotive engine block, along with the macro and micro wear of the cylinder bearing surface. it was found that the commonly used HPDC high-pressure casting technology of Al-Si alloy engine blocks with cast iron liners, in which the cylinder liner is then recreated, does not ensure their metallic connection. The micro-gap created there becomes thicker as the engine is used, which worsens the conditions for heat dissipation from the sleeve to the block. Locally, on the surface of the cylinder bearing surface, reductions in honing effects and longitudinal cracks were observed. The presented literature mechanism of micro wear of the cylinder bearing surface, dependent on the morphology of graphite segregations, was confirmed. The mechanism of creating micro-breaks in the area of phosphoric eutectic and graphite precipitation occurrence was presented, initiated by the formation of microcracks in the eutectic and delaminations at the eutectic-matrix boundary.

Tribological Investigation of The Effect of Aluminum Alloy in Accordance with Cast Iron Liner on Engine Wear

Tribological Investigation of The Effect of Aluminum Alloy in Accordance with Cast Iron Liner on Engine Wear

Structural Performance of Additively Manufactured Cylinder Liner—A Numerical Study

Climate change is exacerbated by vehicle emissions. Furthermore, vehicle pollution contributes to respiratory and cardiopulmonary diseases, as well as lung cancer. This requires a drastic reduction in global greenhouse gas emissions for the automobile industry. To address this issue, researchers are required to reduce friction, which is one of the most important aspects of improving the efficiency of internal combustion engines. One of the most important parts of an engine that contributes to friction is the piston ring cylinder liner (PRCL) coupling. Controlling the linear deformation enhances the performance of the engine and, as a result, contributes positively to its performance. The majority of the tests to study the conformability between cylinder liner and piston were carried out on cylinder liners made of cast iron. It is possible to improve the performance of piston ring cylinder liner couplings by implementing new and advanced manufacturing techniques. In this work, a validated finite element model was used to simulate the performance when advanced manufactured materials were adapted. The deformation of the cylinder liner due to thermal and mechanical loads is simulated with five different additive manufactured materials (Inconel 625, Inconel 718, 17-4PH stainless steel, AlSi10Mg, Ti6Al4V). Simulated roundness and straightness errors, as well as maximum deformation, are compared with conventional grey cast iron liner deformation. Some additive manufactured materials, especially Ti6Al4V, show a significant reduction in deformation compared to grey cast iron, both in bore and circumferential deformation. Results show that Ti6Al4V can reduce maximum liner deformation by 36%. In addition, the roundness improved by 36%. The straightness error when Ti6Al4V was used also improved by 44% on one side, with an average of 20% over the four sides. Numerical results indicate that additive manufactured materials have the potential to reduce friction within the piston liner arrangement of internal combustion engines.

Lubricated friction behaviour of thermal spray steel coated cylinder bores studied using a long-stroke reciprocating tribometer

PurposeThis paper aims to study the effectiveness of using thermal spray (TS) coated bores in reducing friction under the mixed lubrication (ML) and elastohydrodynamic lubrication (EHL) regimes.Design/methodology/approachA reciprocating tribometer with a stroke length of 100 mm, was built to measure the coefficient of friction (COF) at the mid-stroke and ring reversal positions and to conduct sliding tests at a speed range of 0.31–3.14 m/s. Samples taken from fine-honed TS coated bores and also from cast iron (CI) liners that underwent a standard-honing process were tested against ring segments coated with chromium nitride (CrN) and diamond-like carbon.FindingsConstruction of Stribeck curves demonstrated that TS coatings showed a transition from ML to EHL at a lower speed (0.94 m/s) compared with CI (1.26 m/s) regardless of the counterfaces used. Lower COFs of 0.05–0.08 in ML was measured for TS coatings compared with those of 0.06–0.09 for CI in ML. Once EHL was reached, the COF of TS coatings decreased to 0.02–0.03 similar to those of CI. Examination of wear patterns suggested that the low roughness combined with high oil retention capability might be responsible for the reduced transition speed and the expanded EHL region for the TS coated surfaces.Originality/valueWith the EHL friction captured in a bidirectional sliding mode using a long-stroke tribometer, this work contributes to the understanding of the low-friction behaviour of TS coatings.

A Study on Material Properties of Intermetallic Phases in a Multicomponent Hypereutectic Al-Si Alloy with the Use of Nanoindentation Testing.

The paper concerns modeling the microstructure of a hypereutectic aluminum-silicon alloy developed by the authors with the purpose of application for automobile cylinder liners showing high resistance to abrasive wear at least equal to that of cast-iron liners. With the use of the nanoindentation method, material properties of intermetallic phases and matrix in a hypereutectic Al-Si alloy containing Mn, Cu, Cr, Ni, V, Fe, and Mg as additives were examined. The scanning electron microscope equipped with an adapter for chemical composition microanalysis was used to determine the chemical composition of intermetallics and of the alloy matrix. Intermetallic phases, such as Al(Fe,Mn,M)Si, Al(Cr,V,M)Si, AlFeSi, AlFeNiM, AlCuNi, Al2Cu, and Mg2Si, including those supersaturated with various alloying elements (M), were identified based on results of X-ray diffraction (XRD) tests and microanalysis of chemical composition carried out with the use of X-ray energy dispersive spectroscopy (EDS). Shapes of the phases included regular, irregular, or elongated polygons. On the disclosed intermetallic phases, silicon precipitations, the matrix, values of the indentation hardness (HIT), and the indentation modulus (EIT) were determined by performing nanoindentation tests with the use of a Nanoindentation Tester NHT (CSM Instruments) equipped with a Berkovich B-L 32 diamond indenter. The adopted maximum load value was 20 mN.

Restoration of cylinder liners for automotive tractors engines in modern conditions

One of the most promising technologies for restoring machine parts and cylinder liners is electric spark treatment as the most versatile technology that provides high-quality restoration of worn parts with wear up to 0.5 mm. (Research purpose) The research purpose is in developing a technology for restoring various cylinder liners by means of electric spark processing, selecting optimal modes and electrode materials that allow improving the quality of repair and increasing the post-repair life of the sleeve. (Materials and methods) It was taken into account when conducting research aimed at restoring the geometric parameters of the sleeve, that the coating must have sufficient adhesion strength to the surface of the sleeve under mechanical, thermal loads and long-term operation. Laboratory studies of the adhesion strength of electric spark coatings on the separation (adhesive) and on the cut, as well as tribotechnical studies of interfaces were conducted. Authors have found by analyzing the results of operational tests of restored and new cylinder liners the prospects for using electric spark treatment of worn parts, including diesel engine liners. (Results and discussion) It was shown by laboratory studies of the adhesion strength of electric spark coatings with a 0.2 mm thick BrMKc 3-1 electrode to the working surface of cylinder liners that their separation strength (adhesive) was 20-40 megapascals, and the shear strength (cohesive) was 50-80 megapascals. It was found that this provides the required functional strength of coatings with maximum operational load. The article presents the results of comprehensive research in graphs and tables. (Conclusions) The research conducted in the CCP "Nano-Center" of the FSAC VIM and operational tests in the 2nd bus fleet of Moscow confirmed the principal possibility of effectively restoring cast iron liners (blocks) using the technology of electric spark processing.

Plasma-Texturing Surface Treatment of Grey Cast Iron for Friction Reduction

A new surface texturing technique, based on liquid plasma discharging in an aqueous electrolyte, is proposed to modify the surface morphology of grey cast iron. During the process, a grey cast iron sample serves as a cathode where the reduction of hydrogen from the aqueous electrolyte occurs and consequently plasma discharging is generated on the sample surface under applied high voltages (up to 480V). The formed hydrogen bubbles are exploded during the electrical discharging, leaving an irregular array of craters on the sample surface due to the high temperature and shockwaves of the plasma micro-arc discharging. After polishing the crater-like textured surface, surface roughness and oil retention are measured by a profilometer. Reciprocating tribotests are utilized to determine the coefficients of friction. The surface morphology of the polished and tested surface is studied by SEM. The same tests are also conducted for the cast iron with a cross-hatched surface. These two set of results are compared to determine the effects of the texturing and polishing on friction. The results show that the polishing of textured surface can decrease the roughness and coefficients of friction significantly at starved lubricating conditions. This method has potential to be applied on the cylinder bore surface of a cast iron liner for the internal combustion engine (ICE). By honing the textured bore surface, the friction between piston and cylinder bore is expected to decrease and the ICE efficiency to increase for environmental benefits.

Thermal wave interferometry measurements and microstructural analysis of twin wire arc spray cylinder coatings for passenger car engines

With intent to increase the efficiency of combustion engines in passenger cars, thermally sprayed cylinder bore coatings replaced cast iron liners as cylinder running surfaces over the past years. Since the functionality of an engine depends on the life-long integrity of these coatings only a few 100μm thick, monitoring their physical properties in series production is most important. This contribution focuses on the non-destructive testing of thermally sprayed coatings by thermal wave interferometry (TWI), investigating the relationship between thermal and microstructural properties. Microstructural characteristics such as laterally expanded splat interfaces or spherical pores correlate with macroscopic quality criteria such as adhesion, cohesion, or corrosion resistance. Further on, especially splat interfaces act as thermal barriers within the coatings. Hence, TWI thermal diffusivity measurements were compared to optical microscopy images of polished cross sections and three-dimensional X-ray computed tomography data at multiple positions in a crankcase. Both, microscopy images as well as computed tomography data were analyzed quantitatively by image processing algorithms. Due to this, local variations in thermal diffusivity were found, which revealed a significant correlation with microstructural characteristics. Further on, a significant influence of the amount, size, and shape of microstructural volume defects on the local thermal diffusivity of thermally sprayed coatings is carried out in this contribution.

Evaluating Scuffing Failure in Dry Sliding Conditions of Monolayer Chromium Piston Ring/Bulk Grey Cast Iron Liner Interface

Evaluating Scuffing Failure in Dry Sliding Conditions of Monolayer Chromium Piston Ring/Bulk Grey Cast Iron Liner Interface

ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ТЕХНОЛОГИИ МДО ДЛЯ ДВИГАТЕЛЕЙ ВНУТРЕННЕГО СГОРАНИЯ

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

Tribological and Microstructural Properties of Carbon Steel Coatings Fabricated by Wire Arc Spray

Thermal spray is a widely used process employed for the reduction of engine weight by replacing heavy cast iron liners inserted in cylinder bores. In particular, twin wire arc spray (TWAS) is one of the most popular thermal spray processes due to its reasonable cost and high deposition rate. In this study, ferrous coatings were fabricated by using TWAS with two variables: gas type and initial carbon content in wire. The investigation was focused on the relationship between variables and their effects on the oxidation, microstructure, and tribological properties. Especially, for evaluation of the tribological properties, a reciprocating sliding wear test was designed by considering realistic engine conditions. Individual splats forming the coating layer undergo oxidation which results in oxide formation, loss of alloying elements, and heat generation during spraying. From the results of experiments, it was figured out that the oxidation state is controlled by gas type, and its effects on microstructure and coating properties vary depending on the initial carbon content of the wire. Finally, it was confirmed that the wear resistance of the ferrous coating containing FeO and more carbon was better than the other for its improved frictional property and high hardness.

Thermal Stress Analysis of Residual Stress in a Cylindrical Aluminum Casting with Cast-in GCI Liner, Taking Recovery Behavior Effect into Account

Most aluminum cylinder blocks produced using high-pressure or low-pressure die-casting processes require gray cast iron liners (GCI liners) to compensate for their insufficient wear resistance and heat resistance of the Al-Si-Cu alloys. However, the cast-in liners cause excessive residual stress at the cylinder bore region. The resultant residual stress induces distortion of the cylinder liner. These inconveniences hinder development of more efficient engines. Therefore, an accurate thermal stress analysis technique has been sought to predict the residual stress and distortion of the cylinder liner. For accurate thermal stress analysis, we have already developed an elastoplastic-creep constitutive equation for which the inelastic strain developed at high temperatures does not contribute to strain hardening that occurs at low temperatures by duplicating the recovery behavior. Our earlier investigation using this equation has already revealed that incorporation of the recovery in the alloy constitutive equation is effective for improving the prediction accuracy of the thermal stress developed during casting. However, this conclusion was obtained only for a simple shape casting with a uniaxial thermal stress state. Effects of the developed constitutive equation have not been discussed for a casting closer to an actual cylinder block. For this study, a cylindrical aluminum casting with GCI (ISO 300) insert was produced. Then, the circumferential strain of the GCI liner was measured in-situ during casting. Measurements were taken of the residual stresses of the cylindrical aluminum casting and GCI liner, and of the liner deformation at a room temperature. The experimentally obtained results supported a discussion of the predictive accuracies of the elastoplastic-creep constitutive equation and the classical elastoplastic constitutive equation. A comparison revealed that the elastoplastic-creep constitutive equation for the aluminum casting has better predictive accuracy than the classical elastoplastic equation for residual stress, liner deformation, and the circumferential strain of a GCI liner during casting. Investigation of the simulated strain components of the cylindrical aluminum casting during casting indicated incorporation of the recovery in the alloy constitutive equation as a main factor improving the predictive accuracy.

A comprehensive study of the effects of honing patterns on twin-land oil control rings friction using both a numerical model and a floating liner engine

Engine bores are finished with a multi-stage honing process and the finished surface roughness contributes significantly to the piston ring hydrodynamic pressure generation, especially for twin-land oil control rings whose land profile is parallel to the liner surface. In this paper, five different honing patterns on a cast iron liner and one on a spray-coated aluminum liner are studied with a floating liner engine and numerical models. The liner temperature and engine speed were varied such that all the lubrication regimes, namely boundary, mixed, and fully hydrodynamic, are present. It is found that the models based on deterministic approach with a patch of carefully measured liner roughness can match the trend of the Stribeck curves for different liner finishes observed in the experiment. Furthermore, the results show that the roughness height and structure of the honing affect the twin-land oil control rings lubrication differently. With the same honing structure, although rougher liner experiences mixed and boundary lubrication in larger range of Gumbel–Hersey number, it renders less friction than the smoother ones in the hydrodynamic regime. With the same plateau roughness height, a more continuous plateau can provide more flow resistance and thus generate higher hydrodynamic pressure at the ring–liner interface and less friction.

Pulse Eletrodeposition of Ni/nano-Al2O3 Composite Coatings on Cast Iron Cylinder Liner

Ni/nano-Al2O3 composite coating by pulse electrodeposition method has been used for coating on cast iron liner material. The hardness has been increased from 308 HV to 1050 HV through conventional Watts bath and by applying Taguchi's optimization technique with optimum parameters of pulse frequency 120 Hz, duty cycle 40% and peak current density 0.7A/cm2. The lubricant's pH (4) and stirring speed (400 rpm) are the foremost parameters for increasing the hardness of the coating. Furthermore, the pulse current (PC) produces homogeneous distribution of Al2O3 particles in the Ni matrices. The chemical composition, surface morphology, crystal structure, adhesion, coating thickness and the corrosion resistance of the optimized liner specimen of deposited Ni/nano-Al2O3 coatings were evaluated by Optical Emission Spectrometer (OES), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), ASTM D 3359-97, Metallurgical Microscope (ASM standards) and ASTM B117-07 standards.

Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation

A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe) cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS), and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM) is compared at different nominal pressures (40~100 MPa) and temperatures (180~250 °C). With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL), the cast iron liner enters into a “polish wear” stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs.

A Study on the Cavitation Corrosion of Gray Cast Iron Liner by Antifreeze

A Study on the Cavitation Corrosion of Gray Cast Iron Liner by Antifreeze

Correlation of microstructure with tribological properties in atmospheric plasma sprayed Mo-added ferrous coating

Abstract Heavy steel automotive parts have been replaced with aluminum-based lightweight materials worldwide. In particular, grey cast iron engine blocks, which are very heavy components in vehicles, have been replaced by aluminum-silicon hypoeutectic alloys in order to reduce emissions and fuel consumption. However, aluminum alloys are not able to withstand severe engine cylinder conditions due to their poor mechanical properties. In this study, a Mo blended ferrous coating was fabricated using atmospheric plasma spraying to replace the grey cast iron liner in the automotive cylinder bore. Five fractions of Mo, 0, 5, 10, 15, and 20 wt%, with ferrous powder were prepared to investigate the effect of Mo on the microstructure and mechanical properties of coatings. All of the Mo-added coating layers showed significantly improved mechanical properties, such as hardness and wear resistance compared to that of grey cast iron. However, as Mo content exceeded 10 wt% of the blend, the tribological properties gradually degraded due to brittle fracture of Mo. As a result, 10 wt% Mo blended with ferrous powder provided optimized mechanical properties and can be substitute for grey cast iron liners in the automotive industry.

Simulation of Cylinder Deformations during Honing of Thermally Coated Running Surfaces in Crankcases

The internal combustion engine of the future has to cope with increasing high requirements. A large potential is seen in reducing friction in the piston group. For this purpose a coating technology for cylinder running surfaces, including mechanical machining processes was developed. By substituting the compact cast iron liners (4 mm wall thickness) for the thin coating layer (0.1 mm) the normal forces become more important in the honing process. Due to the different stiffness of the crankcase roundness deviations occur caused by the machining forces as a result of elastic deformation. Content of this paper is the calculation of the elastic deformations using the finite element method. Based on a honing tool model, the effective normal forces are calculated, which afterwards are used as input variables for the crankcase model.

The influence of oil supply and cylinder liner temperature on friction, wear and scuffing behavior of piston ring cylinder liner contacts – A new model test

A reciprocating model test has been developed, which reproduces real load situation of the contact condition between the piston-ring and cylinder liner at fired top dead center (FTDC) of internal combustion engines. Friction, wear, and load carrying capacity (LCC) were studied as a function of temperature, oil supply rate, and normal force for a honed gray cast iron liner and a chromium plated piston ring. The results show similar liner wear to the ones in actual fired engine tests were obtained as long as normal forces that correspond to engine combustion pressures were applied. Also, a considerable dependency of the LCC on temperature and oil supply rate was found. However, oil supply rate did not influence coefficient of friction (COF) as much as expected.

Steel coating application for engine block bores by Plasma Transferred Wire Arc spraying process

Thermal spraying development for automotive industry grows since the end of the nineteen nineties. In the case of engine blocks, bores were before plated by a chemical process or liners were inserted in cylinders to ensure the tribological performances. In fact, aluminum has poor wear properties. Nowadays, a lot of research is conducted on the reduction of weight by liner replacement. The main solution is the coating application directly on the aluminum cylinder bore. In this way, weight is reduced and design can be improved to furthermore develop performance and efficiency. Different processes are employed such as plasma, HVOF or electrical arc. One of them is the Plasma Transferred Wire Arc spraying (PTWA) consisting of a plasma jet formed by a transferred arc between a cathode and a wire. Its tip is melted and blown by a gas blast toward the bore surface. This paper presents the PTWA process applied for cylinder bore coating. Typical coating is presented in terms of composition with two arc current intensities used. Tribological tests measurements were done and compared to the previous solution consisting of cast iron liner. Some technical and problematic points are presented around the spraying process in bores.