(A) Study on the Simulation of the Fuel Injection System in a Large Low-speed Marine Diesel Engine

It has been a major research to improve the performance and reliability of diesel engine, since internal combustion engine has been invented originally. However, recently much of these researches are focused on the reduction of exhaust emission for environmental pollution protection with the concerns of the low fuel consumption rate. The charactristics of fuel injection system have a strong influence on the air-fuel mixing process and engine output, thermal efficiency, durability, noise, and exhaust emissions. The performance and exhaust emission of diesel engine is related to the fuel injection rate and injection pressure, injection duration. Combustion in diesel engine is mainly governed by characteristics of fuel injection. In this study, a simulation program was developed, which could simulate a fuel injection system for low-speed marine diesel engine. The fuel injection system was composed of fuel injection pump, high pressure pipe and fuel injection valve. The unsteady flow in the high pressure injection pipe was analyzed by the method of characteristics, considering cavitation and variation of fuel density and bulk modulus. It was assured that the simulation results agree well with experimental results of injection pressure and quantity at the high pressure distributor in fuel injection system for the training ship "M/V Hannara". And the effects of the high pressure pipe length and diameter, plunger diameter, nozzle opening pressure, nozzle hole diameter and maximum needle lift were also investigated utilizing the simulation program developed in this study.Abstract = 4 기호설명 = 6 제 1 장 서론 = 9 제 2 장 연료분사계통의 모델 = 11 2-1 연료분사계통의 작동원리 = 13 2-2 연료순환계통의 구조 = 14 2-2-1 연료펌프 = 14 2-2-2 연료노즐 = 21 2-3 쇽업소버(Shock absorber) = 22 2-4 연료캠 Control 선도 = 24 2-5 주기관 연료 순환 및 공급 선도 = 26 2-6 가변 분사시기 장치(VIT) = 28 2-7 플런저 유효행정 = 32 2-8 펌프 배럴의 연료차단구멍의 유로 단면적 = 34 2-8-1 엔진부하 중지점 이하에서의 유로 단면적 = 34 2-8-2 엔진부하 중지점 이상에서의 유로 단면적 = 37 2-9 연료노즐의 유로 단면적 = 38 제 3 장 연료분사계통의 이론 해석 = 40 3-1 연료분사계통의 기본 가정 = 40 3-2 연료분사계통의 지배 방정식 = 41 3-2-1 연료펌프 = 41 3-2-2 연료노즐 = 42 3-2-3 고압분사파이프 = 44 3-3 각 단에서의 경계조건= 49 3-4 물성치와 계수 = 52 3-5 계산 알고리즘 = 55 제 4 장 실험장치 및 실험방법 = 57 4-1 실험장치 = 57 4-2 실험방법 = 57 제 5 장 결과 및 고찰 = 60 5-1 실험결과와 계산결과의 비교 = 60 5-1-1 연료펌프의 속도변화에 의한 영향 = 60 5-2 분사계의 파라메터에 따른 시뮬레이션과 분석 = 64 5-2-1 분사파이프의 길이 및 직경 변화에 의한 영향 = 64 5-2-2 플런저 직경 변화에 의한 영향 = 67 5-2-3 연료노즐 개방압력 변화에 의한 영향 = 71 5-2-4 노즐 홀 직경 변화에 의한 영향 = 73 5-2-5 노즐 니들밸브 리프트 변화에 의한 영향 = 76 제 6 장 결론 = 78 참고문헌 = 8