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Q4. A. Explain the possible reasons T/C vibration while operating at a steady speed.

B. State how the incidence of turbo charger vibration might be minimized.

C. Explain the action to be taken in order to maintain 2 stroke engine operation in the event of turbo charger having to be taken out of service.

D. Indicate the effect this action will have on engine operation.

{How is the engine operation affected when operated with a by-passed T/C}

Q2. (a) Sketch a sealing arrangement for an oil lubricated stern tube.

(b) Identify the common forms of seal failure.

(c) State how oil loss due to seal failure can be restricted whilst on Passage

(d) How the aft bearing is designed to minimize the concentrated load?

Q9. (a) Why is the axial clearance of a main thrust bearing an important dimension? (6)

(b) How is this clearance measured? (6)

(c) Describe how the thrust pads are removed for inspection and state what you would look for in particular. (4)

Q5. With reference to LNG diesel engine installations:

(a) Describe, with the aid of a sketch, a Gas Valve Unit, explaining its purpose and indicating where it is located in the gas train. (6)

(b) Explain why ventilation and inert gas systems must be installed with the engine fuel gas system. (5)

(c) State why pilot injection must be provided when burning fuel gas, explaining how a pilot injection system works (5)

Q7. With reference to electronically controlled engines:

(a) Describe how fuel injection quantity and timing is adjusted. (6)

(b) Describe how the exhaust valve timing may be varied. (5)

(c) Describe how starting air valves are regulated. (5)

Q9. (a) Define the term Torsional Vibration with respect to an engine crankshaft, stating the effect that high levels can have on an engine crankshaft. (6)

(b) Explain how engine deterioration influences the risk of Torsional Vibration, stating what can be done to minimise that risk. (5)

(c) Explain TWO possible reasons for the activation of a Torsional Vibration alarm after an engine has been started if there had been no previous history of such an alarm and if no maintenance had been undertaken on the engine whilst it was stopped. (5)