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fuel injection systems have made a come back in marine diesel engines, the older mechanically controlled system have been replaced by electronic/hydraulic controlled system.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.

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

Q6. (a) Explain why highly efficient diesel engines tend to produce more NOx than low performance diesel engines.

(b) Describe, with the aid of a sketch, a Selective Catalytic Reduction (SCR) unit for a marine propulsion diesel engine.

(c) Explain why accurate monitoring of the exhaust gas flows entering and leaving a Selective Catalytic Reduction unit are required and how these readings are used to control the reduction chemical supplied to the SCR unit.

Q1. Crankcase oil mist detectors have undergone a lot of changes in recent years. Compare the modern types with multiple sensor units with the traditional single sensor type, where sampling was done sequentially. What is meant be addressable sensors.

Q5. 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.

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

Q7. 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.

Q7. With respect to large two stroke crosshead main engines;

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

B. State how the arrangement describe a achieves its purpose.

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.

Q6. Sketch and show all parts of a two-stroke engine stuffing box. Describe the procedure of overhauling two stroke engine stuffing box, without removing piston. All safety precautions and proper tools used for overhaul to be mentioned. (16)

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)

Q5. Sketch and describe the arrangement of a main engine camshaft chain. Describe the repair procedure following fracture of one chain link during operation of the engine. Give possible reasons for the failure and explain how the chain is set initially at the correct degree of tension.