• Title/Summary/Keyword: bore wear

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A Study on Engine Oil Consumption Considering Wear of Piston-Ring and Cylinder Bore (피스톤-링 및 실린더 보아 마모를 고려한 엔진오일소모 연구)

  • Chun, Sang-Myung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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    • pp.143-150
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    • 2007
  • Ring and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Here, the oil amount through top ring gap into combustion chamber is estimated as engine oil consumption. Furthermore, the wear theories of ring and cylinder bore are included. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. The wear data of rings and cylinder bore are obtained from three engines after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below. It is shown that the important factor regarding oil consumption increasement is the wear of ring face.

A Study on Cylinder Bore Wear during Engine Durability Test (엔진 내구시험 시 실린더 보아의 마모에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.131-136
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    • 2006
  • Cylinder bore wear may not be a problem in most current automotive engines. However, a small change in cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each pare0s wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of cylinder bore diameter are obtained from three engines before and after engine durability test. The calculated wear data of cylinder bore diameter are turn out to be twice of the lower bound of averaged test values at TDC and the lower bound at BDC.

A Study on Engine Durability Considering Oil Consumption and Wear of Piston-Ring Pack and Cylinder Bore (피스톤 링 팩 및 실린더 보아 마모와 오일소모를 고려한 엔진 내구수명 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.155-163
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    • 2006
  • Ring, groove and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face, groove geometry and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blowby and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings, grooves and cylinder bore are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below.

THE STATE OF THE ART OF THE INTERNAL PLASMA SPRAYING ON CYLINDER BORE IN AlSi CAST ALLOYS

  • Barbezat, G.
    • International Journal of Automotive Technology
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    • v.2 no.2
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    • pp.47-52
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    • 2001
  • For the wear protection of cylinder bore in aluminum cast material the internal plasma spraying technology offers a new economical solution. The size and the weight of the engine blocks significantly can be decreased in comparison with the traditional cast iron sleeves. The coefficient of friction between piston ring and cylinder wall sensitively can be reduced and the wear resistance increased from several factors. The paper gives an overview of the technology from the AlSi cast alloys for engine block to the non destructive testing technology used after the machining by diamond honing. The actual results in engines of different types also will be shown. The economical advantages of the plasma spraying (or the internal coating in cylinder bore also will be discussed in comparison with the different alternatives of technology. The aspect of the market introduction also will be discussed in this paper.

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Wear Resistance Characteristics of Thermal Sprayed AlSiMg/SiC Composite Coatings on Aluminum Engine Cylinder Bores (Aluminum Engine Cylinder Bore 적용 AlSiMg/SiC 복합 용사피막의 내마모 특성)

  • 양병모;변응선;박경채
    • Journal of Welding and Joining
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    • v.17 no.6
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    • pp.62-69
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    • 1999
  • The advantages of Thermal sprayed coatings as a replacement for cast iron liners are reduced weight, better heat transfer and reduced cost. One of the most important performance attributes of a cylinder bore coating is its wear resistance, since it must survive the abrasive sliding of both the piston rings and the piston skirt. In this study, composite powders were prepared by ball milling of Al-13Si-3Mg(wt%) alloy with SiC particles. The concentrations of SiC were 40 and 60wt%. The composite powders were sprayed using Metco-9MB plasma torch. Plasma sprayed coatings were heat-treated at 500℃ for 3 hours. The wear resistances of the plasma sprayed coatings were found to improve with heat treatment and superior to the commercially available G.C.I.(gray cast iron). AlSiMg-40SiC heat-treated coatings showed the best wear resistance in this study.

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A Study on Ring Face and Groove Wear during Engine Durability Test (엔진 내구시험 시 링 외주면 및 그루브 마모에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.4
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    • pp.211-217
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    • 2006
  • Ring and groove wear may not be a problem in most current automotive engines. However, a small change in ring face and groove geometry can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings and grooves are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be at the lower bound of aver-aged test values or a little below.

A Study on Effect of Scale Formation in Water Jacket on Thermal Durability in LPG Engine (엔진 물통로 내부 벽면 스케일 축적이 LPG 엔진의 열적 내구성에 미치는 영향에 대한 연구)

  • 류택용;신승용;최재권
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.3
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    • pp.42-50
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    • 2001
  • In this paper, the effects of scale formation in engine water jacket upon the thermal durability of engine itself and its component parts were studied. To understand the effect of quality of water, a full load engine endurance test for 50 hours was carried out with not-treated underground water. The followings were found through the tested engine inspection after the endurance test; 1-2 mm thick scale formation in the engine water jacket, valve seat wear, piston top land scuffing, piston pin stick, and cylinder bore scuffing in siamese area. In order to understand the causes of above test results, the heat rejection rate to coolant, the metal surface temperature of combustion chamber, and the oil and exhaust gas temperatures were measured and analyzed. The scale formed in the engine water jacket played a role as thermal insulator. The scale formed in the engine reduced the heat rejection rate to coolant and it caused to increase the metal surface temperature. The reduced heat rejection rate to coolant increased the heat rejection rate to oil and exhaust gas and increased the oil and exhaust gas temperature. Also, the reasons of valve seat wear, piston top land scuffing and cylinder bore scuffing, and piston pin stick quantitatively analyzed in this paper.

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The development of a wear resistant hard-metal tappet in diesel engines

  • Shim, D.S.;Song, K.C.;Kim, K.W.;Cho, J.W.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.401-402
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    • 2002
  • Diesel engines have many sliding parts with solid body contact. For example, a piston-ring and a cylinder bore, a valve and a valve-seat, a cam and a valve tappet. These parts have a severe wear problem. during engine life times. During these times, the valve tappet has abnormal wear such as scuffing and pitting due to a high hertzian contact stress between the cam and the tappet. Excessive wear problems frequently occur to both the cam and the tappet. To solve these problems, we developed an advanced wear resistant tappet. The developed tappet consisted of a hard-metal wear part and a steel body. To increase a bonding strength, those two parts, were directly bonded to each other. Also to decrease a bonding temperature, we developed the composition of Ni-binder materials in the hard metal. To estimate the wear characteristics of the newly developed tappet, we performed wear tests and engine dynamo tests in order to compare them with a conventional Fe-base tappet. As a result, the newly developed tappet has better wear characteristics than those of the conventional tappet. In addition, we performed a 100,000km field-test, and the newly developed tappet showed much improved wear resistance.

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A study on lubrication characteristics between piston ring and cylinder bore of bent-axis type piston pump for vehicle (차량용 사축식 피스톤 펌프의 피스톤 링과 실린더 보어간의 윤활특성에 관한 연구)

  • Jung, Jae-Youn;Cho, Ihn-Sung;Song, Kyu-Keun;Baek, Il-Hyun;Oh, Seok-Hyung;Jung, Seok-Hoon;Jeong, Yong-Wook
    • Tribology and Lubricants
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    • v.23 no.5
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    • pp.201-206
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    • 2007
  • The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors cannot satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastic hydraulic oil's lubrication analyses of the film thickness, the pressure distribution, and the friction force, and so on, have been performed, and the lubrication characteristics between the piston ring and the cylinder bore are explored by the results of the numerical analysis, and it is contributed to realize the higher efficiency and the more advanced performance of the bent-axis type piston pump.

Measurement of Hydrodynamic Pressure Distribution between a Piston and Cylinder

  • Kim, Y.H.;Park, T.J.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.419-420
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    • 2002
  • The piston-cylinder mechanism is widely adopted in the hydraulic machine components. In these cases, the hydrodynamic pressures are generated in the clearance gap between the piston and cylinder under lubrication action of the oils. Under the eccentric condition of the piston in the cylinder bore, the asymmetric pressure distributions in the circumferential direction result in lateral forces on the piston. When the lateral forces act as increasing the piston eccentricity, excessive wear can be occurs in the cylinder bore and piston. In this paper, the hydrodynamic pressures generated in the clearance are measured using a stationary piston and moving cylinder apparatus. The experimental results showed that the hydrodynamic pressure distributions are highly affected by the eccentricity of the piston.

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