• Journal of Advanced Marine Engineering and Technology
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• 제27권4호
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• pp.520-525
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• 2003

This article provides a dynamic modeling methodology of engines to be accurate with a small number of degrees of freedom for an active vibration control using a top bracing. First. a finite element (FE) model for the engine structure is constructed so that the size of model is as small as possible where the dynamic characteristics of engine are ensured. Second. a technique is studied to obtain the exact mass and stiffness matrices of the FE model. The size of matrices from the FE model is still too large to apply. Finally, a model reduction is. therefore. conducted to make an appropriate dynamic model for designing and simulating a top bracing. In this article, a dynamic model of a large 9 cylinder engine is constructed and reviewed by comparing its natural frequencies and steady state reponses with those of experimental data provided by manufacturer.

• Journal of Advanced Marine Engineering and Technology
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• 제27권3호
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• pp.381-387
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• 2003

Engine noise consists of the noise radiated from an engine structure and noises from engine ancillaries such as a turbocharger fuel injection system, and alternator. The noise of these ancillaries might be incorrectly evaluated in the aspect of the noise contribution to engine noise because the noise reflection effect of their neighbor engine structure is easily ignored. Consequently, noise source identification should be misled. This study investigates the fact that the engine structure located around an alternator reflects alternator noise, and the reflected noise acts as another alternator noise source in a heavy-duty diesel engine. The result shows that the alternator noise can be correctly estimated in engine noise by properly including the noise reflection effect.

• Journal of Advanced Marine Engineering and Technology
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• 제39권10호
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• pp.1049-1053
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• 2015

This paper proposes to include engine information in Maritime Service Portfolio (MSP) for effective implementation of e-Navigation. Even though engine information is one of most important element to e-Navigation, MSP consists of mainly about navigation and communication information not included engine information. Furthermore, in reality, engine information sent from ship side such as mainly noon report and Planned Maintenance System (PMS) is too limited to make e-Navigation possibly. Therefore, Remote diagnostic structure receiving and sending data of engine information must be included in MSP for implementation of e-Navigation. Also, it has to be designed, and developed by Software Quality Assurance (SQA).

• 한국소음진동공학회논문집
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• 제21권2호
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• pp.120-128
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• 2011

This paper presents an efficient method to analyze noise and vibration of marine diesel engines mounted on flexible hull structure. The analysis model should in general include the hull structure, leading to lots of computational efforts. To minimize the computational efforts, in this paper, the transfer synthesis utilizing the receptance at the mounting points is proposed. The procedure is then verified by comparing the results with those from the full model calculation. The effects of flexible hull structure on the acoustic power from engine block are finally investigated. It is found that the effect of the hull is significant when the receptance of hull structure is similar to or greater than that of mount or engine block.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.85-96
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• 1992

Engine enclosures are widely adopted to reduce the noise emission in various fields of application. The radiated noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound power with different path of propagation. One is the 'structure-borne sound power' which stems from the engine's vibratory force applied to the structure of enclosure through the mounting parts of engine etc., while the other is the 'air-borne sound power' which is originated by the sound power radiated from the engine surface to the inner space of enclosure that should excite the vibration of enclosure from inside. In order to get a most efficient engine enclosure is required a profound consideration upon the above structure-borne and air-borne noise, since the guiding principle of countermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subject for the structure-borne sound power and the specifications of absorbing member and damping panels are the major interests for the air-borne sound power. Hence it seems very efficient to separate the total sound power into two categories with a great accuracy when one think of further reduction of engine noise from the exciting enclosure, however, its separating methods have not been made clear for many years. Then author proposes a new practical separation method of two propagation path's contribution to the total radiation sound power for the enclosure under the engine operating condition.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1060-1065
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• 2007

This paper summarizes a design procedure of radiated noise from engine blocks of marine engines. This air-borne noise is one of the significant noise contributors including the aeroacoustic noise due to intake and exhaust and the re-radiation due to structure-borne noise. Excitation forces by engine operations are evaluated taking into account the power generation mechanism from the burning process to the subsequence motion of internal parts; piston, connecting rod, and crank shaft. The acoustic transfer vector method is incorporated to effectively simulate the radiated noise field under the various operation conditions. A contribution analysis for the various excitations to the radiated noise is conducted. It is found that the firing pressure is the main source of the radiated noise, and so the structure of the cylinder can be modified to significantly reduce the radiated noise from the engine block.

• Journal of Advanced Marine Engineering and Technology
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• 제17권4호
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• pp.63-72
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• 1993

This paper deals with the determination of the main design parameters on the efficient .betha. type stirling engine for marine use having the rhombic drive mechanism. This studies are performed as following. (1) The characteristics of $\beta$ type stirling engine, (2) The kinds of driving mechanism, (3) The structure of rhombic drive mechanism, (4) The reasons of making choice of the rhombic drive mechanism in $\beta$ type stirling engines, (5) Ultimately the purpose of this paper is to determine the main design parameters of $\beta$ type stirling engines for marine use having the rhombic drive mechanism. Finally, We can adapt the result of this paper in designing of $\beta$ type stirling engine driven by the rhombic drive mechanism.

• 해양환경안전학회지
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• 제26권1호
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• pp.114-120
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• 2020

본 연구에서는 IMO의 향후 예상 규제 물질 중 하나인 수트를 선박용 엔진을 대상으로는 최초로 배기 수트와 엔진 수트로 구분하여 구조적 특성의 비교 분석을 시도하였다. 그리고 최근 발표되고 있는 배기 수트 재활용 연구의 연장선상에서 엔진 수트의 재활용 가능성 여부를 확인하기 위하여 2,000℃로 열처리를 시행하였고, 열처리 전·후의 수트를 고분해능 전자현미경과 라만분광법을 통해 분석하였다. 전자 현미경을 통한 분석 결과, 배기 수트와 엔진 수트는 유사한 형태의 나노 구조를 가지고 있으나, 배기 수트는 구형의 1차 입자가 체인형 결합구조를 가지고 있었고, 엔진 수트는 배기 수트에 비해 무정형한 구조가 확인되었다. 라만분광법 분석 결과, 배기 수트와 엔진 수트 모두 D peak(1,350 cm^-1)와 G peak(1,580 ~ 1,600 cm^-1)가 확인되었다. 다만, G/D ratio는 엔진 수트에 비해 배기 수트가 상대적으로 높게 나타나며, 이는 배기 수트가 더 흑연화 된 구조를 나타냄을 의미한다. 열처리 후의 분석 결과, 엔진 수트도 배기 수트와 유사하게 흑연화가 문제없이 진행됨을 확인하였고, 이를 통해 선박용 디젤엔진에서 발생하는 배기 수트와 엔진 수트 모두 흑연재료로 재활용이 가능함을 확인하였다.

• 소음진동
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• 제6권4호
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• pp.503-511
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• 1996

There is a tendency of using the resilient mounting system to control the structure born noise transimitted from a engine of which weight is comparatively light and of which speed is comparatively high. According to recent reports, the resilient mounting system is applied to control the vibration of a engine running up to 300 - 400 R.P.M.. Furthermore, the resilient system is also used to the ships such as marine exploring ships, fishing boats, and military vessels. It is not desirous to apply the results for the resilient mounting systems of automobile engines to the controls of the vibrations of marine engines. Marine engines are worked under the idle speed in port and are operated up to the maximum contineous revolution at sea(running up condition). And marine engines are usually worked in inevitable conditions such as a misfire and a cut-off cylinder operating condition. Concerning the above running conditions, a resilient mounting system should be designed in the case of marine engines. In this paper, we studied the effect of engine's misfire on the resilient mounting systems. And the influences of design parameters, such as dynamic characteristics and fitting angles of resilient rubber mountings, were also investigated respectively on the single and double resilient mounting systems.

• 한국소음진동공학회논문집
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• 제19권2호
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• pp.155-161
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• 2009

Engine builders have separately developed and applied torsional, axial and structural vibration monitoring system on most marine engines. These systems displayed their results for engine or ship operation engineers and were not regularly stored at the hardware of computer. So, the history and trend of various engine and hull vibrations were not supported for preventive maintenance and to protect the failure of these activity or function. The integrated vibration or stress monitoring system(EVAMOS : engine vibration analysis and monitoring system) in marine diesel engine, its accessories and hull structure have been developed by the dynamics laboratory of Mokpo Maritime University during last 3 years. This paper introduces the design conception and ability of commercial software EVAMOS with field data on several actual tests.