EKM-Mar-2020

Q1. Explain the functional and constructional diffidence between the Torsional and Axial vibration dampers with the help of neat sketches, Explain the function of the side and Top bracing of the main engine.

Q2. 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.

Q3. Why does 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.

Q4. Main engine fuel injection systems require a lot of attention to ensure optimum performance. As the Chief engineer of a 15 year old vessel which has recently been bought by your company you have found that the main engine fuel system had been poorly maintained. Explain the steps you will take to ensure good standards are brought back. Your answer should be comprehensive, starting from ordering of bunkers.

Q5. 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.

Q6. 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 safety precautions to be observed?

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 increase in cylinder bore. C. Explain how stress concentration and its effects are relieved by maintenance and operational practices.

Q8. With reference to the scavenge spaces of main engines, give reasons for the following faults: (a) Lubricating oil accumulation; (b) Scavenge fires; (c) Water accumulation; (d) High air temperature;

Q9. (a) Describe, with aid of sketches, either an electronic governor or a hydraulic governor. 

(b) Explain how the governor. described in Q.9(a), functions in order to increase fuel to the engine in the event of a load increase. 

(c) State the defects which can impair operation of the governor described in Q. 9(a)