Exam Question
For 2-Stroke Marine Diesel Engine
(a) Describe problems in achieving good lubrication of Cylinder Liner (6)
(b) What are the properties of good cylinder oil? (4)
(c) What are the consequences of under and over lubrication of liner? (6)
Class 4 (4th Engineer)
MEKM
📅 Dec 2024
Reference Answer
### (a) Problems in Achieving Good Lubrication of Cylinder Liner (6 Marks)
Achieving an effective and consistent lubricating oil film on the cylinder liner of a large 2-stroke marine diesel engine is fraught with challenges due to the extreme operating environment and mechanical design constraints. The primary problems are as follows:
1. **Extreme Operating Conditions**:
* **High Temperatures**: The upper part of the liner is exposed to combustion temperatures exceeding 1500°C, while liner surface temperatures can reach 250-300°C. This extreme heat can cause thermal breakdown (cracking) and oxidation of the lubricating oil, reducing its effectiveness and leading to the formation of carbonaceous deposits.
Achieving an effective and consistent lubricating oil film on the cylinder liner of a large 2-stroke marine diesel engine is fraught with challenges due to the extreme operating environment and mechanical design constraints. The primary problems are as follows:
1. **Extreme Operating Conditions**:
* **High Temperatures**: The upper part of the liner is exposed to combustion temperatures exceeding 1500°C, while liner surface temperatures can reach 250-300°C. This extreme heat can cause thermal breakdown (cracking) and oxidation of the lubricating oil, reducing its effectiveness and leading to the formation of carbonaceous deposits.
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