EKM-Oct-2021

Q1. Sketch and describe the arrangement of a main engine camshaft chain. Describe the repair procedure following fracture of one chain link during the operation of the engine. Give possible reasons for the failure and explain how the chain is set initially at the correct degree of tension.

Q2. 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.

Q3. (a) Describe the procedure for checking and adjusting the timing of the main engine fuel injection pump. (b) Explain how diesel engine power balance is achieved, stating why it is essential.

Q4. State how EACH of the following defects becomes apparent, describe its effect on engine operation or safety and indicate the corrective action required to restore normal engine condition; A. Leaking air inlet and exhaust valves; B. Leaking air start valve; C. Cracked cylinder liner; D. Broken piston rings.

Q5. Discuss the consequences of failure to maintain correct clearances in the case of the main diesel engine crankshaft and bottom end bearings. Sketch a bottom end bearing paying particular attention to the arrangement of ensuring uninterrupted flow of oil to the top end bearing.

Q6. with reference to a slow speed diesel engine fitted with a single turbocharger. describe, with reasons, the possible action which could be taken to enable the main engine to be operated, If whilst on oceanic passage, a small portion of one of the impeller vanes breaks off and is impacted with the charge air cooler.

Q7. With reference to the 4-stroke medium speed engines: A. Define the cause and effect of thermal stressing in-cylinder Heads, liners and pistons. B. Explain why thermal stressing are aggravated with an increase in the cylinder bore. C. Explain how stress concentration and its effects are relieved by maintenance and operational practices.

Q8. (a) Describe, with aid of sketches, either an electronic governor or a hydraulic governor. 

(b) Explain how the governor. described in (a), functions in order to increase fuel to the engine in the event of a load increase. 

(c) State the defects which can impair the operation of the governor described in (a)

Q9. (a) Explain fatigue cracking, stating its causes and propagation. (b) Explain, how poor maintenance and engine overload may contribute to the risk fatigue cracking of cylinder head holding studs.