DieselShip's Online Content Library

Q1. With reference to diesel engine crankshafts:

(a) Explain the causes and effects of torsional vibrations; (4)

(b) Explain the term critical speed, starting why the engine should not be continuously operated at this speed. (6)

(c) Explain the term fatigue cracking, starting with reasons, TWO factors which have an influence on the likelihood of fatigue cracking. (6)

Q2. With reference to failure of fuel injector nozzles due to burning:

(a) state, with reasons, THREE possible causes; (6)

(b) write a procedure to be used when investigating the cause of fuel injector nozzle burning; (6)

(c) describe a system which should be operated in order to minimise the risk of future fuel injector nozzle burning. (4)

Q3. A. Describe, with the aid of a sketch, a Selective Catalytic Reduction system, explaining the chemical reaction for reducing NOx and the control system requirements. (10)

B. State two engine-based systems for reducing marine diesel engine NOx, explaining how they reduce NOx level but also increase fuel consumption and CO2 emissions. (6)

Q4. As chief engineer, write a report for the engineering superintendent regarding the checking of a bottom end bearing on a crosshead type main diesel engine, after a high temperature alarm was activated at sea, and the subsequent return to full service of the engine. (16)

Q4. Explain with aid of sketches, the gas combustion process in a dual fuel medium speed main engine, operating with pilot injection. (10)

Explain exhaust is meant by exhaust gas recirculation and how this may be effective in reducing air pollution. (6)

Q6. With reference to abnormal and excessive cylinder liner wear;

(a) Explain how it may be caused, stating how it is detected; (6)

(b) Explain the effects and consequences of excessive cylinder liner wear; (5)

(c) Explain how abnormal cylinder liner wear may be prevented. (5)

Q7. As Chief Engineer write instructions for the checking of the engine Slow Turning System and subsequent monitoring of the engine Slow Turning System. The instruction must take account of problem areas which may be linked to the need for slow turning of an engine whilst selected for standby and prior to an actual start. (16)

Q6. With reference to two stroke, slow speed engines:

Explain what is meant by the term thermal stress and how this can cause cracking of the crown surfaces; (4)

Sketch a cross section of a piston, labelling the MAIN components and indicating coolant flow; (8)

State a cause of EACH of the following defects:

(i) Burning of the crown upper surfaces; (2)         (ii) Carbon deposits in the cooling spaces. (2)

Q3. With reference to turbocharger systems:

Describe how performance of the system is monitored and how the information gathered is used to assess performance; (8)

Describe the arrangements for maintaining the systems in good condition. (8)