EKM-Jan-2020

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 improper lubrication of the liner and piston assembly of a large slow speed engine. B. Describe and state the causes of each of Cloverleafing and Micro-seizure C. List out the composition of a cylinder oil suitable for an engine operating on VLSFO.

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. 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 damper.

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. 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.

Q9. A. Sketch a Main engine starting air distributor and describe how it operates. List the safety devices and interlocks incorporated in main engine air starting system and state the purpose of each.