DieselShip's Online Content Library

Q1. Efficient smooth combustion depends upon some or all of the following: (16)

(a) A sufficiently high temperature to effect ignition

(b) A large delay period or ignition lag

(c) A minimum of after burning

(d) A large and rapid rate of pressure rise during the second stage of combustion

(e) Rapid heat losses to the walls Give the correct answer with adequate justification

Q2. (a) Write a letter to the company Technical Manager Stating with reasons, why the fuel bunkered in the last port is of very poor quality (10)

(b) Briefly describe the mitigatory measures that can be taken to reduce the impact of poor bunker quality (6)

Q3. (a) What are the different types of crankshaft used in marine diesel engines? (10)

(b) Discuss the various factors affecting the failure of crankshafts in marine diesel engine (6)

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)

Q5. Sketch and describe an independent two-stage air compressor. Draw a set of typical indicator diagrams and insert the various pressures and temperatures. Indicate the effect of a leaking HP suction valve and excessive HP clearance volume (16)

Q6.a) How does a modern 4-stroke medium speed marine diesel engine exhaust valve spindle rotate. (8)

b) What happens if the tappet clearance between the rocker arm tappet and the exhaust valve stem is too large. (8)

Q5. Sketch and describe a device employed for continuous monitoring of the viscosity of heavy fuel oil being supplied to a main engine (16)

Q8. (a) With the aid of a block diagram describe the operation of an electronic governor fitted to an auxiliary diesel engine (10)

(b) State the reasons for fitting a droop governor to a diesel generator (6)

Q9. Make a diagrammatic sketch of a jacket cooling water system as applied to a group of medium speed auxiliary diesel engine. Indicate the temperatures and pressures in the system. Describe in particular, the flow of water from entry to the engine, to the outlet from the engine and sketch the more important joints in the system (16)

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. The cylinder liner of one of the unit is cracked inspite of the engine having logged only 300 hours since last overhaul. Make a report of what you feel could be the cause of this mishap (16)

Q3. (a) Briefly explain the construction and functions of a bedplate in a slow speed marine diesel engine? (8)

(b) How is the bedplate fastened to the hull structure? (4)

(c) What is the function of the tie-rod in a slow speed 2-stroke engine? (4)

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.

Q5. (a) Why exhaust outlet of marine diesel engine turbocharger is lower than inlet temperature? (6)

(b) Why do we need an air cooler and why is the scavenge air temperature maintained at 40°C? (10)

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)

Q7. (a) Why do you need an 'over-speed' trip despite a governor being fitted to a marine diesel engine? (8)

(b) With respect to an auxiliary engine governor, what is the significance of: (8)

(i) The Load limit knob

(ii) The compensation

Q8. (a) Explain briefly how the different moving parts of a main engine are subjected to various stresses. (8)

(b) Name the stresses and justify by stating how they originate. (8)

Q1. (a) Describe the procedure for taking crankshaft deflection of Auxiliary Engine, explaining all precautions that must be observed (8)

(b) Explain what deflection readings actually mean and suggest the action which must be taken should readings be outside values recommended by the engine manufacturer. (8)