PADE'의 근사법에 의한 선박용 디젤기관에 탑재된 기계유압식 조속기의 성능개선에 관한 연구

A Study on the Performance Improvement of a Mechanical-Hydraulic Governor used a Marine Diesel Engine by Pade' Approximation

The marine propulsion diesel engine has been widely applied with a mechanical-hydraulic governor to control the ship speed for a long time. However, it is very difficult for the mechanical-hydraulic governor to control the speed of engine under the condition of low speed and low load because of jiggling by rough fluctuation of rotating torque and hunting by dead time. To solve these problems of control systems, the performance improvement of mechanical-hydraulic governor is required. In this paper, dead time in the transfer function of the given control system, which is occurred between fuel injection and power output in a long stroke and low speed diesel engine, is converted into a 2nd order Pade' approximation to linearize the control system for analysis and design of the speed control systems through frequency response method. The influence of the dead time. gain, and damping factor is discussed by using Nichols chart, and the optimal parameters are investigated through the computer simulations. The performance improvement of a conventional mechanical-hydraulic governor is confirmed through the above results.