EKM-Apr-2021 (MUM)

Q1. 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.

Q2.A. Outline the problems associated with effective lubrication of the liner and piston assemble of a large slow-speed engine. B. Describe the appearance and state the causes of each of the following: i. Clover leafing; ii. Micro-seizure C. Describe the composition of a cylinder oil suitable for an engine operating on residual fuel.

Q3. 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.

Q4. With regards to connecting rod ovality of four-stroke diesel Engine. Explain Following. a) Importance of connecting rod ovality. b) Method of measuring the connecting rod ovality. C) Discuss the impact of ovality if it increases beyond the maximum allowance limit. d) Method of ascertaining the elongation of connecting rod bolts.

Q5. 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.

Q6. With reference to piston rings; A. State the reasons for breakage; B. How maintenance and engine operation could minimize breakage; C. Explain the recent developments in the piston rings to minimize breakage.

Q7. With reference to main boiler superheater arrangements: A. Compare the advantages and disadvantages of contraflow with parallel flow design. B. How the element tube banks are supported yet allow for expansion? C. How boiler carryover affects superheater effectiveness?

Q8.Describe the starting and reversing system of an electronically controlled diesel engine and compare with an engine having camshaft and explain the following; A. reduction in air consumption during engine starting; B. Improved performance during astern starting and crash astern.

Q9. A. Sketch and describe the Main engine starting air distributor. 

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