DieselShip's Online Content Library

Q1. A very sudden rise in pressure during combustion accompanied by a metallic, hammer like sound is called knocking of the unit or detonation and usually occurs (16)

(a) Near the end of the pressure rise after ignition of fuel charge

(b) Just before the fuel charge is about to ignite

(c) Immediately after the unit reaches peak pressure and before ignition of fuel

(d) At any stage of the combustion process.

State the correct answer and explain why the other reasons given are not justified.

Q2. (a) List and explain the desirable properties of lubricating oil for different application such as for main engine, auxiliary engine and for cylinder lubrication. (8)

(b) Sketch an auxiliary engine lubricating oil circuit. (8)

Q3. With reference to turbochargers:

(a) Explain the term surging, stating how it occurs, its effect on the turbocharger and how it can be avoided (8)

(b) Describe the procedures for cleaning EACH of the following and explain the precautions which should be taken: (8)

(i) Suction air

(ii) Turbine blades and nozzle ring

Q4. Write short notes on:

(a) Control air dryer (4)

(b) Crankcase door (4)

(c) Auxiliary engine overspeed trip (4)

(d) Fuel oil leak off alarm (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)

Q6. (a) What are the advantages of a thin shell bearing? (4)

(b) What are the typical bearing failures? Discuss at least four bearing failures. (8)

(c) Why is periodic analysis of the lubricating oil important? (4)

Q7. (a) Why tie-rods are provided on a 2-stroke main engine? (6)

(b) Why tie rods are placed close to the centerline of the crankshaft? (5)

(c) What is a tie rod pinch screw? And what is its purpose? (5)

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)

Q9. Indicator cards have shown that one cylinder is high in power although the maximum pressure is low. State the associated effects that this might have on the various instruments of the engine and give a detailed description of the method of rectifying the defect. If this abnormality were not remedied, what might be the subsequent effects on the operation of the engine? State the type of engine to which your answer refers. (16)