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Q4. With reference to abnormal and excessive cylinder liner wear

(a) Explain how may be caused, stating how it is detected: (4)

(b) Explain the effects and consequences of excessive cylinder liner wear (4)

(c)  Explain how abnormal cylinder liner wear may be prevented. (4)

(d) Explain how the liner wear rate is calculated. (4)

--- PREVIOUSLY ASKED AS ---

2021/AUG/02 - 2021/SEP/06

Q6. With reference to large two stroke engine:

(a) Explain how abnormal and excessive cylinder liner wear caused, state how it can be detected:

(b) Explain the effects and consequences of excessive cylinder liner wear

(c)  Explain how abnormal cylinder liner wear may be prevented.

Q7. Analyse the problem of cylinder liner lubrication with reference to oil injection timing relative to piston position, speed and direction of motion. Describe the worst effects of inaccurate lubricant injection timing and how it can have a detrimental effect on developed power in the cylinder. Describe with sketches the arrangement for conveying the oil through the cylinder jacket. (16)

Q1. (a) Explain the factors you would consider in deciding whether to open up a cylinder unit for overhaul? After opening the unit and preparing for assembly, how would you decide whether to renew or re-use piston rings?

(b) List the causes of piston ring failure which may result in gas leakage or ring breakage.

Q5. Slow steaming has become the standard operation mode for many ship operators. Discuss various technical issues connected ‘slow steaming’, with particular reference to: (16)

a) Crosshead bearing damage in T/C cutout mode.

b) Cylinder liner cold corrosion

c) Exhaust valve damages

Q5. Misalignment of the main shafting between engine and propeller causes bearing overloads and shaft stress.

A. State the difficulties associated with checking shaft alignment and the reasons why results are unreliable due to external factors. (5)

B. Explain with a simple sketch how a bearing load is assessed. (5)

C. Explain how uneven loading could be rectified. (6)

Q4. a) What is the purpose and key procedures involved in the running-in process of a engine, and how does this process contribute to the long-term reliability and performance of the engine? (8)

b) What are the common issues that can arise during the running-in period of a engine, and what measures should be taken to monitor and address these issues to prevent potential damage or inefficiencies? (8)