Cylinder Liner Surface Research Articles

Optimization of cylinder liner macro-scale surface texturing in marine diesel engines based on teaching–learning-based optimization algorithm

This paper investigates the effect of optimum macro-scale cylinder liners oil groove on the tribological behavior of large bore marine diesel engines. Parabolic bottom shape grooves are selected as the cylinder liner surface texturing. The grooves have been distributed along the stroke in the form of array of circumferential cells with the axial groove centered in each cell. Teaching–learning-based optimization algorithm is applied to get the optimum dimensions of oil grooves, where the objective is to minimize the cyclic average total friction force between the top compression piston ring and the cylinder liner. Numerical simulation based on Reynolds equation is presented to study the effect of optimum grooves’ dimensions on tribological parameters such as hydrodynamic friction, asperity contact pressure, and hydrodynamic oil film pressure. Results showed that the optimum dimensions oil grooves have a significant effect on the total friction force and the cavitation pressure of the oil film.

典型激光参数对高硅铝合金缸套表面微坑几何形貌影响

典型激光参数对高硅铝合金缸套表面微坑几何形貌影响

Investigation of using pumpkin seed oil methyl ester as a fuel in a boron coated diesel engine

In this study, pumpkin seed oil was converted into biodiesel using alkali-catalyzed transesterification. Physicochemical properties were examined based on ASTM standards and compared with commercial diesel fuel (D-2). To improve the performance of engine, combustion chamber components like piston head, cylinder liner, intake and exhaust valves were thermally coated. Boronizing method was applied for the first time in the coating of conventional cast iron cylinder liner surface to reduce heat transfer. 150 μm thick Fe2B layer was deposited on the surfaces. So, the conventional engine was converted into low heat rejection engine. In order to determine the insulation affect of Fe2B layer, 3-D finite element transient-state analyses were done to the both coated and standard cylinders. D-2 and PSME fuel blends were used as test fuels. Emission and performance of the coated engine (CE) have been investigated for both fuels. CE showed lower emission and higher performance. For D-2 and B-20 fuels; results showed that, CO decreased by 13–15%, HC decreased by 53–36%, smoke density decreased by 15–36%, respectively. But NOx emission increased by 11–37% for D-2/B-20 fuels, respectively. Besides, BTE for D-2/B-20 fuel increased by 10-10% while BSEC decreased by 3–9%, respectively.

Influence of positive texturing on friction and wear properties of piston ring-cylinder liner tribo pair under lubricated conditions

Purpose In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine is dissipated as frictional losses of which major portion is contributed by the piston ring-cylinder liner tribo pair. Hence, proper design of tribological parameters of piston ring-cylinder liner pair is essential and can effectively reduce the friction and wear, thereby improving the tribological performance of the engine. This paper aims to use surface texturing, an effective and feasible method, to improve the tribological performance of piston ring-cylinder liner tribo pair. Design/methodology/approach In this paper, influence of positive texturing (protruding) on friction reduction and wear resistance of piston ring surfaces was studied. The square-shaped positive textures were fabricated on piston ring surface by chemical etching method, and the experiments were conducted with textured piston ring surfaces against un-textured cylinder liner surface on pin-on-disc apparatus by continuous supply of lubricant at the inlet of contact zone. The parameters varied in this study are area density and normal load at a constant sliding speed. A comparison was made between the tribological properties of textured and un-textured piston ring surfaces. Findings From the experimental results, the tribological performance of the textured piston ring-cylinder liner tribo pair was significantly improved over a un-textured tribo pair. A maximum friction reduction of 67.6 per cent and wear resistance of 81.6 per cent were observed with textured ring surfaces as compared to un-textured ring surfaces. Originality/value This experimental study is helpful for better understanding of the potency of positive texturing on friction reduction and wear resistance of piston ring-cylinder liner tribo pair under lubricated sliding conditions.

Effects of thread groove width in cylinder liner surface on performances of diesel engine

The performance of diesel cylinder liner-piston ring (CLPR) friction pairs with different surface textures are very important and affect the service life, reliability, and economy of diesel engines. The aim of this study was to gain insights into interactions between thread groove surface texture (TGT) and the friction and wear behavior of a marine diesel CLPR. Four kinds of TGT with different widths, including 1, 2, 3, and 4 mm, were designed and machined on cylinder liners and then tested using a four-stroke CLPR friction and wear tester. The cylinder liner pressure, contact resistance between cylinder liner-piston ring, and worn surface morphologies of cylinder liners were obtained to examine cylinder liner performance with different width TGT. Compared with untextured cylinder liners, the experimental results showed that TGT significantly affected tribological behavior and consequently affected sealing performance of CLPR systems. Specifically, 3 mm TGT had the clearest effect on CLPR system performance, as the CLPR antifriction performance showed an average friction reduction of 30.9%, oil film lubrication performance, reflected by contact resistance, increased by 33.3%, and sealing performance improved by 14.4%. These results aided in the understanding of specific applications of surface texture on wear performance in CLPR friction pairs which could be applied in slower sliding long stroke marine engines.

Calculation of plasticity index of honed cylinder liner textures

The fundamental objective of this work is to develop method of plasticity index calculation for honed and especially plateau honed cylinder textures. Cylinder liner surface topographies were measured by white light interferometer Talysurf CCI Lite. Honing angle was in the range: 15-700. For each identified summit the ratio of the smaller and the larger radii in the axial and circumferential directions γ1−, was computed. Then the ratios of the radii in orthogonal directions for different orientations (90 resolution) were computed and the smallest value, γ2 was recorded. Average values of these ratios were compared and errors of plasticity index estimation were computed. It was found that for both honed and plateau honed liners only a tolerable level of error is introduced in plasticity index calculations by taking the cylinder axis and circumference as the principal axes. These errors were larger when the honing angles are bigger.

The Effect of Spikes Occurrence on Surface Texture Parameter Assessments

In this paper the influence of measurement errors (spikes) on surface topography parameter valuation was taken into consideration. More than 30 plateau-honed cylinder liner surfaces were taken into account. They were measured by white light interferometer Talysurf CCI Lite. The effect of two types of spikes (upper-spikes and/or lower-spikes) on areal form removal and/or surface texture parameter (from ISO 25178 standard) calculation was taken into account. It was assumed that surface topography parameters were falsely estimated when spikes appeared. Moreover, selection of reference plane was also disturbed when measurement errors (spikes) occurred.

Wear Behavior of CuSn Coated Piston Ring Sliding against Nodular Cast Iron Cylinder Liner under Heavy-Duty Conditions

In order to investigate the friction and wear behavior between the nodular cast iron cylinder liner (Fe) and CuSn coated piston ring under heavy-duty conditions, piston rings with chromium(Cr) coating and CuSn-Cr coating were tested using the piston ring reciprocating liner test rig at the simulated working conditions of 56 MPa, 200 r/min, 190 °C. Compared with the Cr/Fe pair, the CuSn coating consumption of the CuSn-Cr/Fe pair made friction coefficient and cylinder wear loss decrease by 2.8% and 51.5%, respectively. Different size Sn patches worn from the CuSn coated piston ring were embedded into the cylinder liner surface based on the surface topography. This process was shown to reduce the surface roughness of a cylinder liner and form flatter plateau structures. Chemical elements analysis indicated that plateau structures on the cylinder liner surface matched with CuSn-Cr coated ring are helpful to promote the tribo-chemical reaction and generate the reactive products to protect the mutually contacted asperities.

Edge-area form removal of two-process surfaces with valley excluding method approach

This paper analyses the influence of edge-area form removal on surface texture parameters (from ISO 25178 standard). The study focused on assessing the effect of near-edge dimples on surface texture analysis. Areal form removal was performed by means of digital filtering methods (regular Gaussian filter, robust Gaussian regression filter, median filter and/or other algorithms). For minimisation of dimples distortion the valley digital excluding method (VDEM) with standard deviation determination procedure was applied to measure plateau-honed cylinder liner surfaces (more than 20 measured and/or 20 with digitally added dimples surfaces were studied). The measurements were performed with a stylus instrument, Talyscan 150, or a white light interferometer, Talysurf CCI Lite. It was assumed that application of VDEMwith further application of proposed digital filtering algorithms caused the decrease in dimples distortion with accordance to regular Gaussian regression and/or robust Gaussian regression filtering methods. It was also found that the near-edge dimples were more vulnerable to distortion than the centre-located oil pockets.

The influence of roughness distribution characteristic on the lubrication performance of textured cylinder liners

PurposeThe purpose of this paper is to investigate the coupling mechanism of the roughness distribution characteristic and surface textures on the cylinder liner.Design/methodology/approachThe cylinder liner-piston ring lubrication model with non-Gaussian roughness distribution surface was proposed in this paper to find the optimum cylinder liner surface. The motored engine tests were carried out to verify the simulation results.FindingsThe calculation and experiment results show that the large negative skewness surface has the optimal lubrication performance in the un-textured liner, while in the textured liner, the small negative skewness surface is more appropriate, which means surface textures couple with small negative skewness surface can improve the lubrication performance.Originality/valueAlthough there are some works related to liner surface roughness and textures, the combine of roughness distribution and surface textures is not usually taken into account. Therefore, this research is different from others, as the present model considers with real non-Gaussian roughness distribution liners.

Tribotest of engine piston ring/cylinder liner pairs with different nanoparticles added into engine oil

Purpose Wear on internal combustion engines is a loss of material that occurs with the rubbing of the materials in contact with each other and significantly reduces the economic life of the engine. Even the smallest precaution that can be taken to prevent friction and wear in the engines can provide economical savings in very large quantities. Internal combustion engines are widely utilized in modem automobiles. Around 10 per cent of the total fuel energy is dissipated to heat due to mechanical friction, among which 20 per cent is caused by the contact between the cylinder liner and the piston rings. Design/methodology/approach In this study, real piston ring-cylinder specimens were tested with reciprocating tribometer by using five different nanoparticles added to engine oil to investigate their wear and friction behavior. Findings With regard to the experiments, it has been found that the best results were determined by TiO2 and single-walled carbon nanotubes according to boron nitride, multi-walled carbon nanotubes and graphene nanoparticles added to the engine oil, respectively. At the end of the tests, different wear mechanisms have been determined after the surface analyses on the piston ring and cylinder liner surface, and abrasive wear has been observed as the main wear mechanism. Originality/value This paper has an originality with regard to adding different nanoparticles into the commercial engine oil.

Mixed Flow Reactor Experiments and Modeling of Sulfuric Acid Neutralization in Lube Oil for Large Two-Stroke Diesel Engines

Lubrication oil for marine diesel engines contains additives in the form of CaCO3-based reverse micelles, which can neutralize condensing H2SO4, and thereby limit uncontrolled corrosive wear of the piston rings and cylinder liner. In the present work, the neutralization mechanism was studied experimentally and through modeling. Using a mixed flow reactor (MFR), the rate of the acid–base reaction was measured as a function of relevant process parameters. In addition, the competition between CaCO3 reverse micelles and NaOH droplets for a reaction with H2SO4 droplets in a lube oil emulsion was explored in a batch reactor. For the residence times investigated, the results show that CaCO3 conversion is significantly reduced when reaching a critically low Ca/S ratio. Furthermore, a mathematical model for the neutralization of H2SO4 droplets by CaCO3 reverse micelles in lube oil under well-mixed conditions was developed. Both the experimental data and simulations support previous results, suggesting that the limiting step in the neutralization mechanism is adsorption of reverse micelles onto the much larger H2SO4 droplets. Using the video-microscopy experiments of Fu et al. [ Tribol. Lett. 2006, 22 (3), 221], it was possible to estimate kinetic parameters for the adsorption-controlled reaction. The model was used to predict conversion of H2SO4 in a lube oil film at the cylinder liner surface for conditions relevant for a full-scale application. Calculations indicated that H2SO4 may reach the liner surface regardless of how well-wetted the surface is.

Low friction and emission cylinder liner surfaces and the influence of surface topography and scale

A low friction piston ring pack, with tangential load halved, was tested in engines with four different cylinder liner finishes. Oil consumption, oil temperature and liner surface temperature were ...

Reciprocating electrolyte jet with prefabricated-mask machining micro-dimple arrays on cast iron cylinder liner

Cast iron cylinder liner in the diesel engine is putting forward higher requirements on the tribological performance. The micro-texture machined on the cast iron cylinder liner surface has demonstrated the brilliant potential of friction reduction. However, the existing micro-texturing technologies of the cylinder liner have some limitations, such as the workpiece deformation, the low processing efficiency and the high cost of the machining equipment. In the paper, the reciprocating electrolyte jet with prefabricated-mask (REJP) machining technology was used to generate circular dimple arrays on the cast iron cylinder liner. The micro-machining equipment adopts the direct current power instead of the pulse power. The electrolyte jet as the cathode driven by the step-wise motor realizes the reciprocating movement. In addition, the arc shape of the cathode opening is identical with the cylinder liner to guarantee the same inter-electrode gap along the curved liner. After the electrolyte flows out of the cathode opening, three machining areas including the injected area by the vertical flow, the activated area and the wetted area by the horizontal flow, are formed on the cylinder liner surface by the prefabricated-mask. The circular dimple can be uniformly fabricated in arrays with the following optimized machining parameters: cathode velocity = 10 mm/s, electrolyte flow = 45 ml/s, applied voltage = 10 V, electrolysis time = 60 s. By using the prefabricated-mask with the array hole of 800 μm in diameter, the best dimension of micro-dimple is about 43 μm in depth and 822 μm in diameter. Compared with the non-dimpled cylinder liner, the friction coefficient of the micro-dimpled cylinder liner decreases as much as 12.0% under the heavy load of 20 MPa.

Internal Diameter Coating Processes for Bond Coat (HVOF) and Thermal Barrier Coating (APS) Systems

Current developments in different industrial sectors show an increasing demand of thermally sprayed internal diameter (ID) coatings. The most recent research and development is mainly focused on commercial applications such as arc spraying (AS), atmospheric plasma spraying (APS), and plasma transferred wire arc spraying, especially for cylinder liner surfaces. However, efficient HVOF torches are meanwhile available for ID applications as well, but in this field, there is still a lack of scientific research. Especially, the compact design of HVOF-ID and APS-ID spray guns, the need of finer powders, and the internal spray situation leads to new process effects and challenges, which have to be understood in order to achieve high-quality coating properties comparable to outer diameter coatings. Thus, in the present work, the focus is on the ID spraying of bond coats (BC) and thermal barrier coatings (TBC) for high-temperature applications. An HVOF-ID gun with a N2 injection was used to spray dense BCs (MCrAlY) coatings. The TBCs (YSZ) were sprayed by utilizing an APS-ID torch. Initially, flat steel samples were used as substrates. The morphology and properties of the sprayed ID coating systems were investigated with respect to the combination of different HVOF and APS spray parameter sets. The results of the conducted experiments show that the HVOF-ID spray process with N2 injection allows to adjust the particle temperatures and speeds within a wide range. CoNiCrAlY bond coats with a porosity from 3.09 to 3.92% were produced. The spray distance was set to 53 mm, which leads to a smallest coatable ID of 133 mm. The porosity of the TBC ranged from 7.2 to 7.3%. The spray distance for the APS-ID process was set to 70 mm, which leads to a smallest coatable ID of 118 mm.

Evolutions of cylinder liner surface texture and tribological performance of piston ring-liner assembly

Abstract This paper presents the results of the tribological experiments conducted using an oscillating wear tester under lubricated conditions. Specimen from piston ring slid against counter-specimen from cylinder liner. Various surface textures of cylinder liners resulted from honing and/or plateau honing. Tests were carried out for two normal loads of 100 and 300 N at a temperature of 80 °C, the stroke was 3 mm, the frequency was 10 Hz. Each experiment was divided into four time intervals. During breaks between the particular parts of the test, the surface topography of cylinder liners was measured by a white light interferometer. It was found that an increase in the normal load led to an increase in changes of the liner surface textures.

Research on the lubrication performance of engine piston skirt–cylinder liner frictional pair considering lubricating oil transport

In current lubrication analysis of piston skirt, the flooded status is generally considered in the piston skirt–cylinder liner frictional pair in all strokes of an engine operating cycle. However, the quantity of lubricating oil at the entrance of piston skirt cannot always ensure the sufficient lubrication status of piston skirt–cylinder liner frictional pair when the piston moves from the bottom dead center to the top dead center in actual engine. In this article, based on the model of piston secondary motion, fluid lubrication, and lubricating oil flow, the lubrication performance of piston skirt–cylinder liner frictional pair is analyzed, in which the quantity of lubricating oil detained on the surface of cylinder liner after the piston skirt moves from the top dead center to the bottom dead center and is considered as the quantity of lubricating oil at entrance of piston skirt when the piston moves from the bottom dead center to the top dead center. The results show that compared with current analysis, in which the sufficient lubrication of piston skirt–cylinder liner frictional pair is assumed in all strokes of engine, there are remarkable changes for the lubrication performance of piston skirt–cylinder liner frictional pair and the piston secondary motion when the lubrication status of the frictional pair in the upstroke of piston is determined by considering actual lubricating oil transport in the lubrication analysis of piston skirt.

Tribological behavior of the boron succinimide on cylinder liner and piston ring surfaces

In this study, tribological performances of two types of anti-wear additive, boron succinimide anti-wear package and ZnDTPs, were investigated in the cylinder liner and piston ring tribological system with a reciprocating tribotest machine. The tribological performances of oils were evaluated in three main contexts including wear rates, surface tribofilm formation and friction. Results showed that NP-3 (boron succinimide containing) lubrication oil which was environment and catalyst friendly, can be an alternative lubrication oil with its tribological performance due to its friction and wear reduction capacity.

A new approach to the description of height distribution of plateau honed cylinder liner surface texture during the initial stage of wear

This article presents a new approach to the description of the height distribution of plateau honed cylinder liner surface topography after the initial stage of wear. In the literature, the two-Gaussian model is often used to describe the height distribution of cylinder liner surfaces. However, in the case of plateau honed surfaces, during the running-in period different changes of surface take place, mostly involving truncation or plastic deformation processes of the highest summits located in the plateau area. Therefore, to describe the height distribution of plateau honed surfaces during the running-in or initial stage of wear, an analytical model called three-Gaussian was used. This model was applied to determine the surface height distribution of cylinder liner after the initial stage of wear. Many plateau honed surfaces with traces of wear were analysed using this model, and some of them are shown as typical examples in this paper. The results of use of the three-Gaussian model to describe the height distribution of surface texture after the initial stage of wear are compared with the existing two-Gaussian approach. A comparison of the fit of these two models to the height distribution of plateau honed surface texture after the initial stage of wear shows that the three-Gaussian model fits the data better than the two-Gaussian model. The observed, measured and calculated results are elucidated and commented on.

Friction Property of MoS2 Coatings Deposited on the Chemical-Etched Surface of Al–Si Alloy Cylinder Liner

To enhance the friction property of Al–Si alloy cylinder liner in running-in period, MoS2 coatings were electrodeposited on the chemical-etched surface of cylinder liner. The friction coefficient decreased by 15% comparing with the original honed surface, indicating the better friction property. This is because the synergistic action between solid lubricant and etched surface. MoS2 coatings prevent the direct contact between silicon particles and piston ring during friction. At top dead center, the oil film was thinnest and even was broken during the reciprocate friction. When oil film was invalidated, MoS2 coatings undertook lubrication. Then, MoS2 coatings were depleted, and advantage of etched surface became apparent.