진동제어를 위한 엔진 기진력의 최적화

다국어 초록 (Multilingual Abstract)

The diesel engine is often a serious excitation source in ships. Both the varying cylinder gas forces and the reciprocating and rotating mass forces associated with the crank and the connecting rod mechanism produce ample possibilities for excitation of the engine structure itself, the shafting, the surrounding substructures as well as the hull girder. This paper presents a guide for optimization of excitation forces produced by the marine propulsion 2-stroke diesel engine. The computational program for predicting the excitation forces is developed and applied to 2-stroke in-line engines. The object function is defined as the work done by every cylinder excitation force which is related to the mode shape of the diesel engine system, especially in the torsional vibration of the shafting. As a practical application of the presented method. the crank angle of 7 cylinder 2-stroke engine is optimized to reduce torsional vibration stresses on the shafting. Compared with the regular firing angle, about 60 ％ of the 4th order torsional vibratory stress on the propeller shaft can be reduced by optimizing the crank angle irregularly. The usefulness of the presented optimization method is confirmed by the measurements.

참고문헌 (Reference)

1 "디젤엔진에서 기진력 감소를 위한 크랭크 각의 최적설계" 12 (12): 108-115, 2002

2 "Vibration Control in Ships" 1985

3 "The Internal-Combustion Engine in Theory and Practice" The M.I.T. Press ii 8. : 1977

4 "Noise and Vibration Optimised 11-cylinder Diesel Engine for Propulsion of 4800 TEU Container Vessel" 1995

5 "Engine Selection Guide for MC/MC-C Engines" 7. : 2002