EKM-Feb-2019

Q1. 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 is aggravated with increased cylinder bore. C. Explain how stress concentration and its effects are relieved by maintenance and operational practices.


Q2. With reference to 2-Stroke Slow Speed Engine A. Sketch and describe Main Engine Exhaust Valve. B. List out a procedure for test of Main Engine Exhaust Valve after overhaul.


Q3. With reference to mechanical/hydraulic governors: A. Why flyweights are driven at a higher rotational speed than the engine; B. How dead band effects are reduced ; C. How hunting is reduced ;D. How the output torque is increased.


Q4. Describe the phenomena of vibration in marine diesel engine. Explain the terms: (a) Transverse Vibration (b) Torsional Vibration (c) Resonance (d) The role of vibration dampers.


Q5. How can an explosion occur in the starting air line of an internal combustion engine and how can the possibility of such an occurrence be reduced? Sketch and describe devices, which may be fitted to reduce the severity of such an explosion. State the attention which air starting valves should be given before stand by.


Q6. Discuss the consequences of failure to maintain correct clearances in the case of 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.


Q7. 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.


Q8. While operating at Sea during rough weather conditions, fire sparks have been observed coming out from the chimney. On investigation, it has been observed that the fuel contains considerable quantity of water and sludge. As the Second engineer of the vessel. Explain. a. Immediate actions taken to rectify the problem. b. Precautions you take to avoid recurrence of this type of problem.


Q9. With reference to main engine turbocharger; A. Explain why cleanliness throughout the turbochargers system is critical to engine performance? B. Describe in-service cleaning procedure for gas and air sides of a turbocharger indicating safetyprecautions to be observed?


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