Exam Question
With reference to medium speed trunk piston engines:
(a) Explain the purpose of an anti-polishing ring (5)
(b) Describe how effective piston cooling is provided (5)
(c) Where is the thrust bearing fitted and why? (6)
Class 4 (4th Engineer)
MEKM
📅 Aug 2024
Reference Answer
### (a) Explain the purpose of an anti-polishing ring (5 marks)
An anti-polishing ring, also known as a bore polishing ring or anti-carbon ring, is a crucial component fitted at the top of the cylinder liner in medium-speed trunk piston engines. Its primary purpose is to maintain the critical honing pattern (or 'cross-hatch' pattern) on the cylinder liner surface and prevent a detrimental phenomenon known as 'bore polishing'.
**Detailed Purpose and Mechanism:**
* **Prevention of Bore Polishing:**
An anti-polishing ring, also known as a bore polishing ring or anti-carbon ring, is a crucial component fitted at the top of the cylinder liner in medium-speed trunk piston engines. Its primary purpose is to maintain the critical honing pattern (or 'cross-hatch' pattern) on the cylinder liner surface and prevent a detrimental phenomenon known as 'bore polishing'.
**Detailed Purpose and Mechanism:**
* **Prevention of Bore Polishing:**
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