• Tribology and Lubricants
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• v.30 no.1
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• pp.21-28
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• 2014

Damage to the cylinder liner of large ship engines, such as scuffing on the surface, can occur very easily because it is operated in a corrosive environment. This scuffing may be due to oil film destruction and corrosive wear caused by water and sulfur included in the fuel, abrasive impurities, and poor lubricants. Thus, a method for monitoring the condition and diagnosing the failure of the cylinder liner and piston ring is needed. In this study, a reciprocating friction and wear test was carried out with a cast iron specimen, which simulated an engine cylinder in a corrosive atmosphere. The lubricants used were base oil, stirred oil with distilled water, a NaCl solution, and dilute sulfuric acid. The friction coefficient and frequency spectrum were measured using a load cell and acceleration sense in each experimental condition. We then used these results to diagnose the failure of the cylinder liner.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.981-988
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• 2008

This paper describes a development of automatic measuring device for cylinder liner wear amount. An operator should regularly measure the wear amount of the cylinder liner to prevent the wear amount of the cylinder liner from exceeding the maximum limit specific to the engine type. In previous methods. an operator entered the inside of the cylinder liner on a ladder and measured the amount of wear using a inside micrometer. Such method is unpleasant in severe environments and full of hazards. In addition, in order to enter the cylinder, the piston head had to be detached. requiring much time and money. In order to solve these problems, a new measuring device that consists of two measuring units and a special install jig is developed. The measuring units are installed through the scavenging air port by the install jig and measures the wear amount during 1 revolution of crankshaft. so detaching of the cylinder head and entering inside the cylinder liner are not required.

• Tribology and Lubricants
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• v.28 no.5
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• pp.233-239
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• 2012

The engine of a large ship operates under wet conditions using a fuel such as bunker C oil, which includes sulfur and many impurities. A cylinder liner made of cast iron is very susceptible to damage such as scuffing on the surface. This scuffing can reliably be attributed to the destruction of the oil film and the corrosion wear caused by water and sulfur included in the fuel, along with abrasion impurities and poor lubricants. In this study, a reciprocating friction and wear test was carried out with a cast iron specimen, which was used to simulate an engine cylinder in a corrosive environment. Base-oil and stirred oil containing distilled water, NaCl solution, and dilute sulfuric acid were used as lubricants. The friction surface was analyzed using a microscope and EDAX, and the friction coefficient was measured using a load-cell under each experimental condition. We then attempted to investigate the damage to the cylinder liner using the results.

• Tribology and Lubricants
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• v.30 no.6
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• pp.356-363
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• 2014

Marine diesel engines operate in environments in which damage easily occurs from corrosion. Recently, damage to cylinder liners has increased from corrosion wear caused by increased engine power. This damage can cause serious problems in the economy. Thus, many researchers have treated and studied damaged cylinder liners. However, a method is necessary for real-time monitoring of damage to cylinder liners during operation of the engine, before serious damage can occur. This study carries out reciprocating friction and wear tests on a cast iron specimen under various corrosion atmospheres and verifies the variations of friction coefficient and friction surface. Additionally, the friction coefficient and friction status are predicted by using a neural network that learns the vibration and frequency spectrum data from an acceleration sensor. According to our conclusions, amplitude is distributed highly at high frequencies, and values of standard deviation and kurtosis are high when damage to the friction surface is serious. The accuracy rate of the friction coefficient predicted by the neural network is over 80% of the real measured value without NaCl, and application of the neural network is very effective for diagnosing the friction condition and damage to the cylinder liner.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.384-394
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• 2015

The purpose of this study was to evaluate the push-shear bond strength between five commercial zirconia veneering ceramics and zirconia core cylinder, and to investigate the effect of biaxial flexural strength and zirconia liner glass treatments. The biaxial flexural strengths of the veneering ceramics were evaluated by a piston-on-three-ball test. The bond strengths between the Y-TZP cylinder and zirconia veneering ceramics were evaluated using the push-shear bond strength test. The data was analyzed using two-way ANOVA and Scheffe's test. The biaxial flexural strength of Cercon ceram kiss (CE) was higher than those of the other groups. The glass-treated and Triceram zirconia groups showed the highest value and the Creation ZI(CR) showed the lowest. In all groups, the liner glass treatment groups showed significantly higher push-shear bond strength than those without(P<0.05). The liner glass treatments of zirconia can improve the bond strength between the zirconia ceramic core and veneering ceramics.

• Journal of Power System Engineering
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• v.11 no.4
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• pp.18-25
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• 2007

제 2세대 직접분사식 가솔린 기관에서 6공 연료분사기의 연료분무특성을 관찰하였다. 실험에 사용한 직접분사식 가솔린 기관은 2개의 흡입밸브와 2개의 배기밸브를 갖는 텀블형 Spray Guided 연소실과 Quartz로 제작된 실린더 라이너와 실린더 헤드 창으로 구성되어 있다. 선회유동을 유도하기 위하여 흡입매니폴드에 선회유동 제어밸브를 부착하였다. 2차원 Mie 스캐터링 기법을 이용하여 연료분사시기, 연료분사압력과 실린더 내 유동 및 냉각수 온도가 연료분무에 미치는 영향을 관찰하였다. 실험결과로는 흡기과정동안 흡기 선회유동은 분사된 연료의 공간적 분포에 크게 작용하였고, 압축과정동안에는 텀블 및 선회유동의 영향이 흡기과정에 비해 크지 않음을 확인하였다. 또한 성층연소를 위해서 압축과정에서 연료를 분사하는 경우 고압의 연료분사압은 분무도달거리의 성장을 촉진시키나 상승하는 피스톤과 이로 인한 실린더 압력의 상승으로 분무도달거리의 성장이 억제됨을 확인할 수 있었다.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.55-62
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• 1985

This study modeled in axisymmetric solid elements and analyzed the neighbourhood of the contact surface zone between liner and block in a diesel engine. The results of finite element analysis show that this model is deformed by bolt jointed load and pressure load and that stresses can vary much due to major dimensional changes in the joint area. Guidelines have been developed for selecting fillet radii and for the width of the contact area between liner and block.

• Journal of Korea Foundry Society
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• v.24 no.4
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• pp.225-230
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• 2004

Computer simulation of mold filling and solidification has been performed in order to analyze the flow and solidification phenomena for the casting process of cylinder liner. The simulation result of mold filling shows that the molten metal flows into the mold in stable without scattering. The simulation results of solidification indicate that the last solidified area is located in the feeder. The temperature variation in casting is measured in actual casting and the result is compared with calculation result.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.124-124
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• 2012

접촉운동기구 계면에서의 마찰력은 요소 혹은 시스템의 효율과 직접적으로 연관이 있으며 이로 해 마찰계수를 낮추기 위한 저마찰 표면처리는 Tribology 연구에 있어 기초적이면서도 동시에 매우 중요한 부분으로 오래 전부터 인식되어오고 있다. 또한 대부분의 습동기구 표면이 경화 처리되어 마모에 강한 특성을 보이나 이는 마찰계수가 일정 이하로 낮게 유지될 경우에만 해당되는 것으로 마찰계수의 조절은 매우 중요하다고 할 수 있다. 과거 자동차 엔진의 실린더 라이너 표면에 가공된 사선 형태의 패턴들이 저마찰 기능을 하는 것은 이미 잘 알려진 사실이며 최근에는 이러한 패턴 혹은 형상을 인위적으로 조절하여 저마찰 기능과 성능을 더욱 높이고자 하는 연구가 활발히 진행되고 있다. 이와 같은 미세한 패턴은 다양한 가공기술의 발전에 의해 가능하게 되었으며 그 결과 마찰계수는 패턴의 형상과 분포 등과 매우 밀접한 관계가 있는 것으로 보고되어 있다. 본 연구에서는 최근 활발한 연구가 진행되고 있는 표면 텍스쳐링 분야에 대한 전반적인 연구 동향과 미래의 가능성에 대해 살펴보고자 한다.

• Tribology and Lubricants
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• v.14 no.4
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• pp.37-43
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• 1998

The friction loss between piston rings and cylinder liner is due to the tension of the piston rings. Lubricant is usually supplied to reduce the friction. However, the sliding speed of the piston varies during the reciprocating cycle and is very low near TDC(Top Dead Center)/BDC(Bottom Dead Center), where the hydrodynamic lubrication cannot be sustained. Since the lubrication regime is shifted from the hydrodynamic to the boundary lubrication near TDC/BDC, wear particles are easily generated so that the friction loss becomes bigger and bigger due to the plowing effect of wear particles. In this study, for the purpose of reducing the friction loss, an undulated surface is adopted to the cylinder liner to trap wear particles. The friction force variations, which are measured by strain gaged, show that the concept of undulated surface is one of the promising methods to effectively reduce the friction between piston rings and cylinder liner.