선박용 메인엔진의 실린더 비활성화에 따른 축계 비틀림 진동 평가

Abstract

A major issue for shipping companies in recent years is to reduce fuel costs and reduce emissions of greenhouse gases that are harmful to the environment for the purpose of increasing operational efficiency. Since fuel cost accounts for a high proportion of the total operating cost of a ship, decelerating operation can be flexibly dealt with in response to changes in market conditions such as fuel cost reduction, but its effectiveness can vary greatly depending on the type of operation of the ship. In addition, driving at a slow speed for a long time adversely affects engine management and may cause an accident due to a decrease in engine output. To solve this problem, we propose a method of deactivating the operating cylinder to reduce the rated output of the engine so that the engine efficiency and performance are optimal even at low engine speed, at this time, the concept of readjusting the angle of the cylinder to offset the unbalanced power applied to the crankshaft was created. Here is a way to operate with half of the cylinders deactivated so that the detonation of each cylinder is performed at equal intervals without adjusting the crank angle. Cylinder deactivation technology can reduce fuel consumption and reduce carbon dioxide by deactivating half of the cylinders in the low and medium load region and increasing the load on the remaining active cylinders. In this paper, cylinder deactivation technology is introduced as one of the methods to improve the energy efficiency of ships, and it is confirmed that the fuel consumption rate can be reduced in the low load operation area when the cylinder is deactivated. By comparing the vibratory force of torsional vibration for the normal operation and the cylinder deactivation operation, it was confirmed that when the cylinder was deactivated, the vibrating force increased steeply in all orders, and the torsional vibration excitation force increased at the same rotational speed. By analyzing the torsional vibration of the 8-cylinder, 10-cylinder and 12-cylinder engine shaft systems, it was confirmed that the results satisfies the classification requirements for normal operation and cylinder deactivation operation. Considering the above, it is judged as an alternative to deactivation of cylinders in the low-load operation area as a method of reducing fuel consumption during deceleration operation according to the shipping company's operation schedule. In addition, it is thought that it will be possible to satisfy the mandatory and strengthened international air environment regulations for greenhouse gas reduction by reducing carbon dioxide emissions by reducing fuel consumption during cylinder deactivation and improving the energy efficiency of ships.