EKM-Dec-2020

Q1. With reference to bridge control of a large slow speed propulsion engine; A. How is starting and reversing achieved? B. Investigate and suggest remedial action required if the engine,(i) Fails to turn on air; (ii) Turns on air but fails to fire on fuel; (iii) Fails to reverse.

Q2. A. Sketch and describe Main engine starting air distributor. 

B. List the safety devices and interlocks incorporated in main engine air starting system and state the purpose of each.

Q3. (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.

Q4. A. Discuss the various types of indicator diagrams and discuss the relevance of this method of determining engine performance. B. Suggest how engine performance may be assessed other than by taking indicator cards.

Q5. With reference to medium speed engine cylinder liners: A. Explain the cause and effects of Polishing or glazing; B. Describe, with the aid of sketches, an anti-polishing ring; C. Explain the action of anti-polishing ring during the operation of the engine.

Q6. A. Describe how a crank pin bearing of a 2 stroke main propulsion engine is opened up for inspection; B. Which half of the bearing is subject to greater wear? C. What are the various causes of wear down of the bearing.

Q7. Fatigue is one of the main causes of crankshaft failure. A. Indicate on a Sketch the most likely location of a fatigue crack; B. How is a fatigue failure identified; C. Describe initiation of a fatigue crack; D. Sketch and Describe the methods used to inhibit fatigue cracks.

Q8. A. Explain the possible reasons T/C vibration while operating at a steady speed; 

B. State how the incidence of turbo charger vibration might be minimized; 

C. Explain the action to be taken in order to maintain 2 stroke engine operation in the vent of turbo charger having to be taken out of service; 

D. Indicate the effect this action will have on engine operation.

Q9. Sketch and describe the arrangement of a main engine camshaft chain. Describe the repair procedure following fracture of one chain link during operation of the engine. Give possible reasons for the failure and explain how the chain is set initially at the correct degree of tension.