• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.416-422
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• 2007

Prime movers in most large merchant ships adapt two stroke low speed diesel engine which has higher efficiency, mobility and durability. However, severe torsional vibration in these diesel engines may be induced by higher fluctuation of combustion pressures. Consequently, it may lead sometimes to propulsion shafting failure due to the accumulated fatigue stresses. Shaft fatigue strength analysis had been done traditionally in time domain but this method is complicated and difficult in analysing bi-modal vibration system such as the case of cylinder misfiring condition. In this paper authors introduce an assessment method of fatigue strength estimation for propulsion shafting system with two stroke low speed diesel engine in the frequency domain.

• Journal of Advanced Marine Engineering and Technology
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• 제31권3호
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• pp.207-214
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• 2007

Theoretical analysis on transient torsional vibration was started from the early 1960s for high power synchronous motor application. Particularly. its simulation and measuring techniques in marine diesel engine field have been steadily studied by some classification societies and large marine diesel engine designers. This paper introduces the simulation method on transient torsional vibration of two stroke low speed diesel engine using the Newmark method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.901-906
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• 2001

Finite element method is used for the structural analysis of low speed large diesel engine structures, and the kinematic and mechanism analysis is performed to compute loads applied to the engine structures. A typical diesel engine is used as an example and static and dynamic structural analyses are demonstrated. Dynamic stress of engine is measured during the sea-trial operation of the ship.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.376-381
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• 2009

The increasing needs for higher cargo capacity in the container vessels' fleet has led to ship builder's demand for higher power output rating engine to meet the propulsion requirement, thus, leading to the development of super large two stroke low speed diesel engines. This large sized bore engines with more than 12 cylinders are capable of delivering power output up to more than 100,000 bhp at maximum continuous rating. The thrust variation force due to axial vibration occurring in propulsion shafting of these ships are transmitted to ship structure via thrust bearing. This force may vibrate the super structure of ship in the fore-aft direction and the fatigue strength of crank shaft can be decreased by additional bending stress increase in crank shaft pin and journal. In this paper, the axial vibration of propulsion shafting system on the 14RT-flex96C super large diesel engine with 14 cylinders is identified by theoretical analysis and vibration measurement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.110-118
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• 2014

In the past two stroke low speed diesel engine were widely used for marine propulsion. these engine have many merit for example, higher thermal efficiency and durability. however, shaft vibration problem was continuously rise up due to large power of two stroke low speed diesel engine. specially, the initial stage engine revolution counter & stress has acculated. For that reason, sometimes occurred crankshaft crack accident. In this study, regarding the initial stage engine, trying to analyze what is cause the crack phenomenon using by latest torsional vibration calculation program & measurement equipment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.830-835
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• 2002

Theoretical analysis about transient torsional vibration was started from early 1960's for high power synchronous motor application. Especially, its simulation and measuring techniques in marine engineering field have been steadily studied by classification societies and designers of large diesel engine. In this paper, the simulation method of transient torsional vibration of two stroke low speed diesel engine using the Newmark method are introduced.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.24-29
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• 2007

Low-speed Diesel Engine, 7K60MC-S, in Power Plant have been experienced high vibration frequently since these units were completed the construction works, but they did not have any fundamental vibration solutions up to date. Therefore, several vibration tests and analyses are conducted to identify the root cause of high vibration and to suggest the optimal countermeasures for diesel engine. The 9.25Hz & 25.4Hz vibrations have been observed on main body during operation. The magnitude of engine upper structural vibration is generally similar in horizontal transverse direction. However, differences in the 'Fore' and 'After' vibration magnitude at 9.25Hz occurs due to the inertia momentum added by SCR duct system with the same vibration phase angle. It is analyzed that the excess structural vibration be occurred when the natural frequency of engine body is accessed the exciting sources due to the explosion pressure and the discharge pulsation of 7 cylinders in resonance range.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.37-45
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• 2003

The diesel engines was invented a little more than one hundred years ago and has ever since been developed for better fuel economy, increased power and smaller size. Thanks to its fuel economy, the diesel engine is today the dominating prime mover in many applications, such as smaller power plants, commercial ships, trains, trucks, buses and all kinds of mobile construction machinery. As engine for passenger cars, the diesel engine is steadily increasing its share of the market. However, its versatility and, consequently, large prevalence have led to environmental demands to its exhaust emissions, noise and vibration. This paper deals with the noise aspects of diesel engine designs of the so-called low speed two-stroke type installed in most large ships.

• 대한기계학회논문집
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• 제16권8호
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• pp.1575-1582
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• 1992

본 연구에서는 정상운전 중인 4사이클 6실린더 터보과급 디젤기관에 갑자기 큰 부하가 작용하였을 경우, 기관 및 과급기 관성 모멘트의 변화가 기관과 과급기의 실제 회전속도, 압축기 압력비, 실린더내 공기유량, 연소효율, 배기온도 등의 과도 응 답성능에 미치는 영향을 시뮬레이션해석과 실험을 통하여 규명하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.551-558
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• 2004

Recently, fuel prices have been continually raised in diesel engine. Such a change in the fuel price influences enormously the development trend of marine diesel engines for slow speed, In other words, the focus was shifted from large diameter and high speed to low fuel consumption. Accordingly, more efforts are being made for engine manufacturing and development to develop highly efficient engines. In this study. a single cylinder 4 stroke cycle DI slow speed diesel engine was designed and manufactured, a 4 stroke cycle was configured and basic performances were evaluated. The results are as follows. The optimal fuel injection timing had the lowest value when specific fuel consumption was in BTDC 8~$10^{\circ}$, a little more delayed compared to high speed diesel engines. Cycle variation of engines showed about 5% difference at full loads. This is a significantly small value compared to the cycle variation in which stable operation is possible, showing the high stability of engine operation is good. The torque and brake thermal efficiency of engine increased with an increase of engine 250-450 rpm. but fuel consumption ratio increased from the 450 rpm zone and thermal efficiency abruptly decreased. Mechanical efficiency was maximally 70% at a 400 rpm that was lower than normal engines according to the increase of mechanical frictional loss for cross head part. The purpose of this study was to get more practical engines by comparing the above results with those of slow speed 2 stroke cycle diesel engines.