DieselShip's Online Content Library

Q1. The main requirements which a fuel injection system must fulfil are (16)

(a) Accurate metering of small amount of fuel oil

(b) Control of quality of fuel injection

(c) Proper timing of the fuel injection

(d) Selective distribution of the fuel in the combustion space

State whether each one of the points made above are true or false with reasons.

Q2. Explain the advantages of fitting highly rated medium speed engines with double exhaust and air inlet valves (6)

(b) State the disadvantages of double valve arrangements (4)

(c) Explain the possible causes of persistent burning of exhaust valves if it is:

(i) General to most cylinders (3)

(ii) Specific to a single cylinder (3)

Q3. (a) Describe means of recognizing deterioration of the lubricating oil (8)

(b) Describe how lubrication oil is conveyed to top end, bottom end and main bearing in large bore 2-stroke crosshead type slow speed diesel engine, you are familiar with (8)

Q4. (a) State the different types of turbo charger fitted in modern diesel engines (8)

(b) Describe the function of the (8)

(i) Nozzle ring

(ii) Labyrinth seals

(iii) Diffuser and

(iv) Inducer

Q5. Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearing. Describe the procedure of taking crankshaft deflection (16)

Q6. (a) Describe with the aid of a sketch, a charge air cooler (10)

(b) State why it is necessary to maintain correct charge air temperature (6)

Q7. (a) Describe, with the aid of a sketch, a main engine cylinder relief valve. (10)

(b) List four conditions which may cause the valves sketched in (a) to lift (6)

Q8. (a) What do you understand by Specific Fuel Oil Consumption? Give some examples of SFOC for a two stroke engine and the auxiliary engines. (6)

(b) Explain the terms: (10)

(i) Flash point

(ii) Pour point

(iii) Calorific value

(iv) CCAI value

(v) Octane number and

(vi) Cetane number

Q1. Compare the desirable qualities of the lubricating oil selected for each of the following duties:

a) Auxiliary diesel engines. (4)

b) Stern tube bearings. (4)

c) Refrigeration compressors. (4)

d) Gear case of purifier. (4)

Give reasons for the differing properties of the oils recommended for these four purposes.

Q1. An auxiliary engine under load continuously fluctuates even with a steady load. The fault you diagnose could be owing to: (16)

(a) The quality of fuel

(b) The quality of servicing of the governor in the last port

(c) The supply of charge air

(d) The overhaul of fuel injectors done in the last decarbonization Give a brief explanation as to why each of the above mentioned points either could be true or cannot at all be the reasons for such a fluctuation.

Q2. With reference to a 2- stroke slow speed main propulsion engine air starting system:

(a) State, with reasons, three safety features incorporated in an air starting system (8)

(b) State with reason why an engine may fail to turnover on air (8)

Q3. Discuss the precautions, which can be taken to minimize the possibility of a diesel engine crank case explosion and the transmission of dangerous flame into the machinery space.

(a) By design and equipment (8)

(b) By operating personnel (8)

Q4. (a) What are the causes of Turbocharger surging? How is it indicated to the watchkeeper? (8)

(b) What are the possible remedial action? (4)

(c) What are the reasons for excessive fouling of the turbocharger? (4)

Q5. With reference to the diesel prime movers for generators in unmanned machinery spaces:

(a) Outline the monitoring and control equipment designed to protect the engine. (8)

(b) Describe the methods employed to test the monitoring and control equipment, during a routine check. (8)

Q6. With reference to medium speed trunk piston engines:

(a) Explain the purpose of an anti-polishing ring (5)

(b) Describe how effective piston cooling is provided (5)

(c) Where is the thrust bearing fitted and why? (6)

Q7. (a) Sketch a section through the bedplate and A frame of a large slow speed engine, identifying parts, method of construction and materials (10)

(b) Explain the function of the tie bolts and how after an alignment problem, these would be tightened (6)

Q8. (a) (i) Describe with the aid of a sketch, a main engine exhaust valve which is hydraulically operated (8)

(ii) Explain the operation of this valve (4)

(b) State the materials used for the seat and valve described in (a) (4)

Q9. Discuss the causes, possible associated hazards and lowering of thermal efficiency consequent on poor combustion in a Diesel engine cylinder. Illustrate your answer by means of indicator cards (16)