Cylinder Liner Wear Research Articles

高速舶用機関の運転実態と機関トラブル発生の関係について―高速舶用主機のアンケート調査結果

Most domestic high-speed ferries are powered by high-speed diesel engines with speeds above 1000 rpm. It is said that operator claims for engine failures of high-speed vessels remain high in comparison to conventional vessels. We considered that various engine failures were associated with the maneuvering patterns of high-speed ferries, such as short passages, fast turnarounds, etc. Our questionnaire survey of failures in high-speed diesel engines during the past five years covered the ship operating conditions, including ship speed during cruising, navigation distance, running hours, and number of round-trip crossings per year. We divided the engine into five basic failure areas for ease of analysis. The most frequent engine failures were crankshaft failure, main bearing failure, camshaft failure, and cylinder liner wear and cracks. The number of failures per year was associated with total navigation distance per year and engine load in cruising conditions.

Pattern recognition on diesel engine working condition by using a novel methodology — Hilbert spectrum entropy

In this paper, a novel method of diesel engine pattern recognition is introduced. Hilbert spectrum (HS) and information entropy are combined to form the Hilbert spectrum entropy (HSE) which is able to give an accurate entropy estimation for Hilbert spectrum. It is more convenient and visual to pattern recognition and fault diagnosis. Experimental data of piston and cylinder liner wear rates obtained from a production diesel engine is used to evaluate the newly developed method. A good conclusion has been reached. Hilbert spectrum entropy is a more advanced method, owing to its numerical outputs, for pattern recognition and fault diagnosis of diesel engines.

A rig test to measure friction and wear of heavy duty diesel engine piston rings and cylinder liners using realistic lubricants

Laboratory tests to evaluate piston ring and cylinder liner materials for their friction and wear behavior in realistic engine oils are described to support the development of new standard test methods. A ring segment was tested against a flat specimen of gray cast iron typical of cylinder liners. A wide range of lubricants including Jet A aviation fuel, mineral oil, and a new and engine-aged, fully formulated 15W40 heavy duty oil were used to evaluate the sensitivity of the tests to lubricant condition. Test temperatures ranged from 25 to 100 °C. A stepped load procedure was used to evaluate friction behavior using a run-in ring segment. At 100 °C, all lubricants showed boundary lubrication behavior, however, differences among the lubricants could be detected. Wear tests were carried out at 240 N for 6 h at 100 °C with new ring segments. The extent of wear was measured by weight loss, wear volume and wear depth using a geometric model that takes into account compound curvatures before and after testing. Wear volume by weight loss compared well with profilometry. Laboratory test results are compared to engine wear rates.

EVALUATION OF FILTERING ELEMENTS AND ITS EFFECT ON AIR FILTER PERFORMANCE CHARACTERISTICS

The air filtering element in any internal combustion engine greatly influences the performance and service life of the engine. The pressure drop across the air filter affects the engine power. Furthermore, the fine dust carried by the air permeated through the filtering element remarkably affects the development of wear in cylinder liners and piston rings. Therefore, a great care should be given to the selection of filtering element in the process of engine design.This paper presents a set of experiments conducted in order to investigate the characteristics of six different types of commercial filtering elements used in the production of local air filters. Two paper, two synthetic, and two wire types of filtering elements were selected for this purpose. They were tested for the resistance characteristics at different values of air flow rate in natural room conditions. For measuring the efficiency and capacity characteristics of filtering elements, tests were conducted at constant air flow. In general the paper type was found to have higher pressure drop and higher efficiency but with lower capacity to retain dust compared to synthetic and wire materials. Analysis of the results in addition to conclusions are included.

Combustion characteristics of trouble-making bunker fuel oil

Low-grade fuels with unusual distribution of distillation temperature and a high rate of aromatic hydrocarbons are currently being supplied at certain ports. Sometimes these fuels cause damage i.e. abnormally heavy wear of cylinder liners to marine diesel engines. In this study, a sample of such a fuel is obtained and its properties and composition are in detail analyzed. Combustion characteristics are examined using various testing devices including visual engine and visual combustion chamber. These are new facilities for study of bunker fuel oil. According to results of such examinations, a cause of the heavy wear of the cylinder liners can be guessed with good confidence.

Prediction of liner wear by extending the Kragelskii model for wear of roughness peaks in sparse contact

The known wear model of Kragelskii for surfaces considers elastic loading of the normal roughness peaks in sparse contact by the shear load along the direction of sliding. Repeated stressing of the peaks causes fatigue to detach material in the form of wear debris. In this paper, an attempt is successfully made to predict the wear of cylinder liners of wide-ranging surface finishes and material strengths, by extending the model to take into account surfaces that do not have normally peaked roughness. The roughness peaks are modelled as tiny hemispheres. The radius of the hemisphere is defined as the geometric mean of the radii in the directions transverse and longitudinal to machining. The transverse radius can be estimated using the actual roughness trace. An alternative and quicker method is presented here to derive this radius as a function of the number of roughness peaks per unit length, the peak roughness, Rp k, and the fraction of the bearing surface MR 1 at Rp k. The latter radius along the machining direction is typical of the machining process. The wear rate of a normal finish is known to be a strong function of the maximum deviation of the roughness trace from the mean line, Rp. The valley portion of roughness, R vk, does not take part in wear as actively as the roughness parameter, R k, lying between Rvk and Rpk. A general surface roughness, which is not normally peaked, is characterized by the plateauness ratio, R k/ Rvk. In the present work, an equivalent roughness Rp-eq for such a general surface is found to bear a unique relation with the plateauness ratio. To study surfaces of general roughness, the equivalent Rp-eq and the radius of the hemispherical roughness peak were substituted in the wear model known for surfaces with normal roughness. Ten different liner surfaces reported in the literature were studied using the present model. In addition, experiments were conducted on a 105mm bore diesel engine using normally honed liners to apply the wear model. A satisfactory correlation was obtained between the predicted wear rates and those measured with the model. Finally, the results are discussed in the light of wear predicted by Archard [3, 11].

The effect of thermal barrier coatings on diesel engine performance

An experimental study of the effects of thin thermal barrier coatings on the performance of a diesel engine was conducted. Results obtained from the engine with thermally insulated pistons were compared with the baseline engine data. Engine trials demonstrated good properties of both coating systems. Temperature and stress distributions within the pistons were evaluated analytically by means of the Cosmos/Works FEM code. Results of a road test on a gasoline-engine-driven car are also reported. The performance of the modified engine-driven car was found satisfactory. The ceramic coating did not produce observable knock in the engine, no significant wear of piston skirts or cylinder liners was found.

A study on effects of recirculated exhaust gas upon wear of cylinder liner and piston in diesel engines

The effects of recirculated exhaust gas on the wear of cylinder liner and piston were experimentally investigated by a two-cylinder, four cycle, indirect injection diesel engine operating at 75% load and 1600 rpm. For the purpose of comparison between the wear rates of the two cylinders with and without EGR, the recirculated exhaust gas was sucked into one of two cylinders after the soot in exhaust emissions was removed by an intentionally designed cylinder-type scrubber equipped with 6 water injectors (A water injector has 144 nozzles of mm diameter), while only the fresh air was inhaled into the other cylinder. These experiments were carried out with the fuel injection timing fixed at 15.3° BTDC. It was found that the mean wear rate of cylinder liner with EGR was greater in the measurement positions of the second half than those of the first half, that the mean wear rate without EGR was almost uniform regardless of measurement positions, and that the wear rate of piston skirt with EGR increased a little bit, but the piston head diameter increased, rather than decreased, owing to soot adhesion and erosion wear, and especially larger with EGR.

障害を発生するバンカー油の燃焼可視化研究

Lately, a kind of low-grade bunker fuel oil is being supplied for marine diesel engines at certain ports and causes them severe troubles like abnormal wear and scuffing of cylinder liners. The authors have got the sam-ples of such fuels and examined their combustion characteristics using a visual combustion chamber. It is a new facility for study of bunker fuel combustion. According to results of examinations, a cause of the trouble can be guessed with good confidence.

Modern heavy duty diesel engine cold start wear study

Increasingly stringent European market requirements for improved heavy duty diesel engine performance, such as fuel economy and durability, continue to highlight the need for higher performance engine lubricants. To meet this need, new additive technology is being used in combination with higher quality base‐stocks and has resulted in a growing trend towards the use of oils of lower viscosities than those used in the past. Such a trend has led to some concern over the ability of low viscous oils to maintain adequate engine wear protection, not only during extended service operations but also under the more severe conditions of low temperature engine start‐up. This paper describes the results of a recent study to evaluate the effect of base oil composition and viscosity grade on the low temperature performance of a modern Euro II diesel engine with respect to wear, using the technique of Thin Layer Activation. Engine test results showed that the use of full synthetic SAE 5W40 grade oils based on Polyalphaolefin provided enhanced low temperature cylinder liner wear protection.

大形外航船舶における機器トラブルシューティング

With the successive introduction of larger and faster ships, two components are needed: high-output propulsion engines and highly efficient engines. This requirement has been fulfilled with extensive research and studies of the engine manufacturers along with all kinds of feedback from the users. However, it appears that the engine safety margin has been sacrificed somewhat in the process of engine development to meet the above requirement.For example, abnormalities in combustion chamber-related components on high-output engines with large bore sizes are major concerns to be resolved. In addition electric power consumption on recent ships has increased with the delivery of lager ships. A large number of electrically operated control systems have been adopted on ships, and proper handling and maintenance of the electric feeding device have become increasingly important.In view of these concerns, marine engineers are making the utmost efforts to keep the ship's schedules, maintaining the safe operation of the engin plant. I would like to take this opportunity to explain how to cope with the unexpected abnormalities and introduce two cases of trouble shooting which I experienced on board.One problem is the abnormal wear of piston rings and cylinder liners, and the other is the malfunction of the generator and the electric feeling control system.Hopefully this report will serve as a useful reference for marine equipment manufacturers, marine engineers and the concerned parties. In addition we hope that the manufacturers will take our requests as direct feedback from the“engine room”and understand the circumstances pertaining to marine equipment operation.

A method of measuring ‘zero‐wear’ of the cylinder liner

AbstractIn this paper, new methods of linear wear estimation of the cylinder liner are proposed. They can be used if the deepest honed valleys remain unaltered during the wear process. In the first part of the paper, the possibility of using various amplitude parameters as measures of wear is studied. The second part presents a new procedure for cylinder liner wear analysis based on the ‘fax‐film’ method that allows us to estimate the wear of the cylinder liner without disassembly of the cylinder‐piston‐piston ring group.

In Situ Wear Measuring Technique in Engine Cylinders

An in situ wear probe was developed to measure the rate of cylinder liner wear and its roughness at the top ring reversal point where severe wear can occur. The wear probe can be removed from the cylinder block and replaced without the need for engine disassembly. The wear probe is scanned at a laser stylus surface measuring station where its topography and wear are analyzed. The engine used is a single-cylinder, air-cooled gasoline engine. A sample of the surface properties and analysis is given. Experimental data are given for the wear rate and different roughness parameters and their variation over the first few hours of the break-in period. Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

Break-In Liner Wear and Piston Ring Assembly Friction in a Spark-Ignited Engine

Cylinder liner wear and surface roughness were measured at the topping reversal point of a single-cylinder, air-cooled, spark-ignition (gasoline) engine during break-in. In addition, the instantaneous factional torque of the engine was determined and correlated with the wear rate and surface roughness during this period. The engine friction, liner surface roughness and wear had their highest values at the beginning of the break-in period. The wear rate dropped sharply during the first hour, after which it maintained a steady lower rate. The surface roughness and friction took longer than the wear rate to stabilize. Friction was found to change in three modes. The first mode took one hour and was characterized by a sharp drop in wear rate and a small drop in friction. The second mode was a transition to the third mode, and took about 2.5 hours. The third mode lasted about 20 hours and was characterized by a drop in both surface roughness and friction. The wear rate did not change much during this mode. After the third mode, the friction and surface roughness changed at a slow steady rate. The total test took 28 hours. Correlations developed for wear rate, surface roughness and friction indicated that friction was a linear function of the surface roughness over the whole period. However, friction was not an indicator of the wear rate. Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

Alternative to chrome: HVOF cermet coatings for high horse power diesel engines

High velocity oxygen fuel sprayed face coatings have shown great promise for piston rings used for high power density diesel engines. Various coatings have been tested on both wear test rigs and in an engine. A highly dense HVOF cermet coating was developed with reasonable crack resistance during service. The HVOF coated piston rings wore three to six tunes lower than chrome plating. Cylinder liner (counter face) wear was found to be one to three times higher than chrome. The HVOF coating is considered to be an excellent replacement for chrome plating. The coating process is more environmentally friendly than the chrome plating process. Also, the coating has potentially lower or equivalent production cost when compared to chrome.

Effect of SO2 in Recirculated Exhaust Gas on Wear in Diesel Engine. (Effect of SO2 Added to Intake Air on Wear).

In both spark ignition engines and diesel engines, the exhaust gas recirculation (EGR) system is well known as an effective technique to reduce nitrogen oxides emissions. However, wear of piston rings and cylinder liners is sharply increased by EGR. It is widely considered that sulfur dioxide contained in exhaust gas is strongly related to wear. In order to clarify the sole effect of sulfur dioxide in recirculated exhaust gas on wear of piston rings and cylinder liners, we performed an experiment where sulfur dioxide was added to the intake air. Furthermore, we compared the amount of wear, which was measured experimentally, with the amount of sulfur dioxide absorbed by a lubricating oil film, which was estimated by a numerical model. Consequently, sulfur dioxide absorbed by a lubricating oil film plays an important role on wear of piston rings and cylinder liners.

Topographic features of cylinder liners — an application of three-dimensional characterization techniques

Studies of wear patterns on engine cylinder liners show that radial wear is greatest on the anti-thrust side, and close to top dead centre. As a result of this wear, surface topography features at different positions exhibit different characteristics. Quantitative representation of the features is helpful for functional analysis and functional control of cylinder liner manufacture. In this paper three-dimensional characterization techniques are applied to produce a comprehensive characterization of cylinder liner wear at different longitudinal positions. The areal autocorrelation function and the areal power spectrum reveal the changes in topographic features. The different topographic features of newly created, after running-in, severely worn and bore polished surfaces of cylinder liners are identified by quantitative functional indices. The characterization techniques and parameters used in the paper constitute an effective approach to the characterization of surface topography of cylinder liners and other tribological surfaces.

Effect of SO2 in Recirculated Exhaust Gas on Wear of Diesel Engine. Effect of SO2 Added to Intake Air on Wear.

In both spark ignition engines and diesel engines, the exhaust gas recirculation (EGR) system is well known as an effective technique to reduce emitted nitrogen oxides. However, wear of piston rings and cylinder liner is sharply increased by EGR. It is widely considered that sulfur dioxide contained in exhaust gas is strongly related to wear. In order to clarify the effect of sulfur dioxide only on wear of piston rings and cylinder liner, we performed an experiment on the addition of sulfur dioxide to intake air. Furthermore, we compared the amount of wear, which was measured experimentally, with that of sulfur dioxide diffused into a lubricating oil film, which was estimated by a numerical model. Consequently, it was found that sulfur dioxide absorbed into a lubricating oil film played an important role on wear of piston rings and cylinder liner.

Piston ring coatings for high horsepower diesel engines

Thermal-spray-deposited face coatings were developed for a top compression piston ring operating under the high pressures and temperatures of high horsepower diesel engines. Coatings were deposited by plasma spray and high velocity oxygen fuel (HVOF) techniques onto the piston ring faces. The coatings were evaluated by wear and engine tests. Three coatings were deposited by a plasma spray technique: molybdenum/chromium carbide, molybdenum/molybdenum carbide, and chromium oxide. Nickel chromium/chromium carbide powder was deposited by a HVOF technique. On the basis of wear and engine testing, HVOF nickel chromium/chromium carbide, plasma-sprayed chromium oxide and plasma-sprayed molybdenum/chromium carbide were identified to have wear resistances superior to that of today's electroplated chromium and molybdenum carbide coatings. Cylinder liner wear was found to be generally equivalent or lower for the thermal spray coatings when compared with the electroplated chromium.

Effect of SO2 Concentration in Recirculated Exhaust Gas on Wear of Disel Engines. Relationship between amount of SO2 absorbed into oil layer and wear.

In both spark ignition engines and diesel engines, the exhaust gas recirculation (EGR) system is well know as an effective technique to reduce nitric oxide emission. However, it has not been applied practically to heavy-duty diesel engines because wear of piston rings and cylinder liner is increased by EGR. It is widely considered that sulfur oxide in exhaust gas strongly relates to the wear. This paper presents a numerical model to reveal the mechanism of wear which estimates the amount of sulfur oxide diffused into lubricating oil film. The calculated results show that the sulfur oxide concentration in the oil layer is related strongly to the EGR rate, inversely with engine speed, and decreases under light load conditions. There is a good agreement between the results and the experimental facts.