Q6. Write short notes on:
(a) Main air starting valves (4)
(b) Exhaust valve rotator (4)
(c) Scavenge relief valve (4)
(d) Function of Labyrinth Seals in turbocharger (4)
Q5. A large marine diesel main propulsion engine, speed fluctuates all the time during the voyage. Make written statements to the chief engineer explaining the observation of various engine parameters, during the voyage which could be indication of some fault, causing engine speed fluctuation. (16)
Q8. (a) Explain briefly how the different moving parts of a main engine are subjected to various stresses. (8)
(b) Name the stresses and justify by stating how they originate. (8)
Q3. (a) Sketch a typical power indicator card for a slow speed marine diesel engine.
(b) Explain how the card may be used to assess the power developed in the Cylinder.
Q7.a) Explain the function of the crosshead guide shoe in a main engine. How is the crosshead guide shoe lubricated? (8)
b) Briefly discuss the maintenance carried out on guide shoe. How can improper maintenance affect the engine’s operation and lead to potential damage. (8)
Q5. With reference to crankcase diaphragm glands: Explain why effectiveness deteriorates in service.
A. Describe the procedure for renewal of parts so that efficiency is restored. (6)
B. Describe how effectiveness is restored if spares are unavailable. (5)
C. Explain the functions of the upper and lower sections. (5)
Q9. With reference to engine inlet and exhaust valves:
(a) State why tappet clearance is essential and why it must be periodically checked. (6)
(b) List with reasons the likely consequences of excessive and insufficient tappet clearance. (4)
(c) State how carbon build-up can occur during engine running and indicate the possible effects on cylinder performance. (6)
Q4. In a situation where the main engine control system suddenly fails, and it is not possible to rectify this immediately
A. Explain the action that a 2nd engineer should take. (8)
B. State the instruction that the 2nd engineer should issue in order to ensure the continued safe and effective operation of the engine. (8)
Q1. (a) How is fuel (HFO) for a marine diesel engine (main engine) being delivered from a fuel oil storage tank up to the combustion chamber? Explain with a line diagram. (10)
(b) What is the significance of the following:
(i) Heating arrangement with temperature control. (3)
(ii) Prevention of air lock in the system. (3)
Q7. Recent experience has shown persistence damage occurring on seating faces of main engine exhaust valve, which is not confined to any particular unit; (a) State with reason the possible causes; (b) State the short-term action to be taken in order to minimize engine operational problem; (c) State with reason how future incident of this nature could be minimized
Q5. (a) Sketch and describe a device employed for continuous monitoring of the viscosity of heavy fuel oil being supplied to a main engine (8)
(b) Explain how the system employing the device described in (a) operates to adjust the fuel viscosity. (8)
Q9. (a) Describe how it is determined whether a crankshaft was twisted during a major “smash up” in a main engine.
(b) Explain where twisting is most likely to occur.
(c) Specify with reasons the degree of twisting that might be accommodated without correction
(d) Explain briefly what adjustments and precautions should be instituted when putting an engine with a twisted crankshaft back into service.
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