DieselShip's Online Content Library

Q1. (a) Explain the factors you would consider in deciding whether to open up a cylinder unit for overhaul? After opening the unit and preparing for assembly, how would you decide whether to renew or re-use piston rings?

(b) List the causes of piston ring failure which may result in gas leakage or ring breakage.

Q2. A. Sketch and describe a control system for maneuvering a main diesel engine from the bridge

B.  Explain how local control may be effected in case of breakdown of the control system described in 2 (A).

Q6. (a) Explain fatigue cracking, stating its causes and propagation.

(b) Explain, how poor maintenance and engine overload may contribute to the risk of fatigue cracking of cylinder head holding studs.

Q4. Misalignment of the main shafting between engine and propeller causes bearing overloads and shaft stress;

A. State the difficulties associated with checking shaft alignment and the reasons why results are unreliable due to external factors;

B. Explain with a simple sketch how a bearing load is assessed.

C. Explain how uneven loading could be rectified

Q5. With reference to the crankshaft and running gear of an engine, explain static balance, Dynamic balance, Torque reaction couple, and Critical speed

Q2. A. Explain the term Variable Injection Timing (VIT) when applied to fuel pumps and state why a change in timing of fuel injection may be required.;

B. Describe, with the aid of sketches a VIT fuel pump and explain how the change in timing is achieved whilst the pump is in operation

C. Explain how it may be determined that individual fuel pumps are injecting the correct quantity of fuel with the correct timing at a particular pump setting.

Q7: Using sketches explain the difference between “Pulse” and “Constant Pressure” turbocharger systems.

(a) In the event of one of the pulse turbocharger’s becoming inoperative due to mechanical breakdown explain the modification required to allow the engine to operate safely.

(b) State the instruction you as second engineer would issue regarding the additional engine monitoring requirements following the steps taken in (a).

Q8. (A) A set of indicator diagrams including draw cards has been taken for a main diesel engine, noted that compression curve is normal. Examine critically and give reasons for following observations.

i. The maximum pressure is lower;

ii. The maximum pressure is higher;

iii. The expansion curve is lower;

iv. The expansion curve is higher.

(B). Describe how the faults as mentioned above can be rectified

Q9. Write a report to the engineering superintendent regarding the replacement of the fuel injectors of three main engine units due to severe erosion of the nozzle holes and burning of the injector tips. Explain in your report how the defects were detected, the likely cause of the damage and the action taken to prevent further incidents of this type.