Question 16 DDE04 - Designated Duty Engineer - 1000-4000 HP

The Correct Answer is B. The item number representing the lubricating oil filter is **5**. In a typical forced-lubrication system for marine diesel engines, the oil must be continuously filtered to remove contaminants, sludge, and wear particles before being recirculated to the bearings and moving parts. Item 5 is positioned downstream of the oil cooler (4) and upstream of the main engine lubrication points (12), which is the standard location for the main engine lubricating oil filter in this type of system layout. **A) 2 is incorrect.** Item 2 represents the **Lubricating Oil Pump**. This pump draws oil from the sump (1) and provides the necessary pressure to circulate the oil throughout the system. **C) 10 is incorrect.** Item 10 typically represents the **Pressure Regulating Valve** or a control valve that dictates the flow of oil to a specific component, such as the Governor, or regulates system pressure by returning excess oil back to the pump suction or sump. **D) 12 is incorrect.** Item 12 represents the various **Main Engine Lubrication Points**, such as the main bearings, connecting rod bearings, camshaft bearings, and turbocharger bearings, where the clean, cooled oil is delivered under pressure.