Analisis Tidak Sempurnanya Pengabutan Injektor pada Mesin Induk No 1 di TB Nisrina Riski Samudera

Abstract

Uncomplete fuel atomization in the No. 1 main engine injector of TB Nisrina Riski Samudera VII was associated with reduced engine performance, elevated exhaust gas temperature, black smoke, and abnormal engine vibration during operation. This study aimed to identify the causes of incomplete injector atomization, describe its effects on main-engine performance, and determine corrective actions. A descriptive qualitative approach was applied during the sea-practice period on board the vessel. Data were obtained through direct observation, interviews with engine-room crew, documentation, and review of ship and engine references. The findings showed three dominant technical conditions: carbon deposits partially blocked the nozzle holes, injector-spring elasticity decreased so that opening pressure fell below the specified value, and the injector needle became dirty and stuck. The injector test recorded about 28 MPa (290 kg/cm²), whereas the manual-book value used in the study was 34 MPa (350 kg/cm²). The incomplete spray pattern contributed to incomplete combustion, exhaust-gas temperature of 550–600 °C, black smoke, unstable combustion, and a reduction of engine speed to around 1200 rpm under high towing load. Cleaning the nozzle and needle, replacing the weakened spring, periodically replacing the fuel filter, cleaning the fuel tank, and retesting injector pressure restored the spray pattern to normal at 34 MPa.