DieselShip's Online Content Library

Q1. Common rail fuel injection systems have made a come back in marine diesel engines, the older mechanically controlled system have been replaced by electronic/hydraulic controlled system. Describe, with a line diagram any one type of a modern CR system, mentioning the engine type. (8)

b) Compare the advantages and disadvantages of the common rail fuel injection systems with the jerk type of injection system. Give examples of their use in modern diesel engines. (8)

Q2. a) What is the meaning of “de-rating” of machinery? (5)

b) Explain the principles behind de-rating a ship propulsion engine as a retro fit and the benefits. (6)

c) Can a de-rated engine be run at full power? If yes, under what conditions? (5)

Q3. Crankcase oil mist detectors (OMD) have undergone significant changes in recent years. Compare the modern multiple sensor type,  with the traditional single sensor type OMDs. where sampling was done sequentially. What is meant by addressable sensors? (16)

Q4. Discuss the significance of cylinder lubrication in two stroke diesel engines considering the impact of Annex VI of Marpol 73/78. Explain:

(a) Two level cylinder lubrication incorporated on few diesel engines. (8)

(b) The effect of over and under lubrication on engines. (8)

Q5. With regards to modern diesel engines revolution pick up sensor. discuss with suitable diagram the following:

a) functioning of revolution pick up sensor.

b) adjustment of pick up sensor.

c) adjustment of rotary encoder.

d) adjustment of pulse angle offset. (16)

Q6. With respect to large two stroke crosshead main engines;

A. Sketch and describe a crosshead designed to prevent or minimize bearing edge loading. (8)

B. State how the arrangement describe a achieves its purpose. (4)

C. What would be an acceptable range of bearing clearance for the top end bearing and bottom end bearings of a large two-stroke marine diesel engine. (4)

Q7. a) To improve the power-to-weight ratio of an engine, it is necessary to increase the MEP. Discuss the importance of turbocharger compression ratio in this regard. Why has it become necessary to introduce two-stage turbocharging? (8)

b) With reference to turbochargers with variable turbine area, explain (8)

i) Which area is varied

ii) Why is it varied

iii) How is it varied.

Q8. Explain why the use of residual fuels for the operation of large slow speed or of medium speed engines, may be responsible for the following problems with turbocharger nozzles, shrouds and blades and how in each, the problem may be minimized:

A. Build-up of deposits.

B. Hot corrosion.

C. Erosion (16)

Q9. (a) Explain fatigue cracking, stating its causes and propagation. (8)

(b) Explain, how poor maintenance and engine overload may contribute to the risk of fatigue cracking of cylinder head holding studs. (8)