Exam Question
(a) Describe with suitable sketches, how lubricating oil is conveyed to top end, bottom end and main bearings in a large bore slow speed engine. (10)
(b) List the causes leading to sudden loss of lubricating oil pressure in the engine.
Class 4 (4th Engineer)
MEKM
📅 Aug 2023
Reference Answer
### (a) Lubricating Oil Conveyance in a Large Bore Slow Speed Engine
#### **1. Overall System Concept**
The lubricating oil system in a large bore, slow-speed, two-stroke crosshead engine is a high-volume, relatively low-pressure (typically 3-4 bar) forced circulation system. Its primary functions are to lubricate moving parts to minimize friction and wear, cool bearings and pistons, and clean the engine internals by carrying away wear debris and contaminants.
The system begins at the engine sump, from which two (one running, one standby) main lubricating oil pumps take suction. The oil is discharged through coolers (using LT Central Cooling Water as the medium) and a full-flow duplex filter battery before entering the main oil distribution gallery, which runs longitudinally along the engine's bedplate.
#### **1. Overall System Concept**
The lubricating oil system in a large bore, slow-speed, two-stroke crosshead engine is a high-volume, relatively low-pressure (typically 3-4 bar) forced circulation system. Its primary functions are to lubricate moving parts to minimize friction and wear, cool bearings and pistons, and clean the engine internals by carrying away wear debris and contaminants.
The system begins at the engine sump, from which two (one running, one standby) main lubricating oil pumps take suction. The oil is discharged through coolers (using LT Central Cooling Water as the medium) and a full-flow duplex filter battery before entering the main oil distribution gallery, which runs longitudinally along the engine's bedplate.
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