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Q5. (a) Explain the term torsional vibration, indicating the effect this can have on an engine crankshaft.

(b) Explain why a detuner/vibration damper might be fitted to an engine.

(c) Explain why an engine might have a barred speed range and why the engine should not be operated continuously in that range. (5)

Q1. With reference to an engine air starting system

(a) Explain why a slow turning is fitted

(b) State, with reasons, when a slow turning system operates

(c) Describe, with the aid of a sketch, an air starting system, explaining how the slow turning system operates.

Q7. a) Describe, with the aid of a sketch, a main engine holding down system explaining how the design features help prevent excessive stress in the holding down studs (8)

b) Describe, with the aid of a sketch, an engine top bracing arrangement, explaining why they are fitted and checked for operational performance (8)

Q4. With reference to abnormal and excessive cylinder liner wear

(a) Explain how may be caused, stating how it is detected: (4)

(b) Explain the effects and consequences of excessive cylinder liner wear (4)

(c)  Explain how abnormal cylinder liner wear may be prevented. (4)

(d) Explain how the liner wear rate is calculated. (4)

Q5.a) Sketch a commonly employed method of attachment between crosshead and slippers. (8)

b) Explain why guide clearance is strictly limited. (4)

c) Give reasons why lubricant is usually fed to the slippers and not the guides. (4)

Q6. a. Describe, with the aid of a sketch a diesel engine fuel system which employs direct injection of liquid gas into the cylinders. (12)

b. Explain the advantages of this type of gas injection system compared with the use of gaseous fuel in the form of gas. (4)

Q7. With reference to a Closed Loop engine exhaust gas SOX scrubber system:

a. Describe, with the aid of a sketch, such a system; (8)

b. State, with reasons, the fluid which is used for SOX scrubbing in this system; (4)

c. State how the effectiveness of the scrubbing fluid is maintained and how the sludge is removed and disposed of. (4)

Q8. With reference to Main engine crankshafts:

a) Explain the term axial vibration

b) Describe, with the aid of a sketch, how axial vibration may be minimised

c) State with reasons which bearing would be most at risk due to the effects of axial vibration

d) Describe how damage to the bearing stated in part (c) may be repaired.

Q9. With reference to a waste heat boiler/economiser:

a. Write a procedure for the cleaning the gas side of a waste heat boiler/economiser when the associated main engine is:

(i) running; (5)

(ii) stopped. (5)

b. Write a procedure for operation of the main engine when the associated waste heat boiler/economiser cannot be operated due to tube failure. (6)