Marine Engineering Knowledge (Motor)

An auxiliary engine under load continuously fluctuates even with a steady load. The fault you diagnose could be owing to

(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 decarbonisation

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. (16)

(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)

Discuss the precautions, which can be taken to minimize the possibility of a diesel engine crank case explosion and the transmission of dangerous flame into the machinery space.

(a) by design and equipment (8)

(b) by operating personnel (8)

(a) Describe means of recognizing deterioration of the lubricating oil. (8)

(b) Describe how lubrication oil is conveyed to top end, bottom end and main bearings in large bore, 2 stroke cross head type slow speed diesel engine, you are familiar with. (8)

Write short notes on:

(a) Main air starting valves (4)

(b) Exhaust valve rotator (4)

(c) Scavenge relief valve (4)

(d) Function of Labyrinth Seals in turbocharger (4)

With reference to medium speed trunk piston engines:

(a) explain the purpose of an anti-polishing ring; (5)

(b) describe how effective piston cooling is provided; (5)

(c) where is the thrust bearing fitted and why? (6)

(a) Sketch a section through the bedplate and A frame of a large slow speed engine, identifying parts, method of construction and materials. (10)

(b) Explain the function of the tie bolts and how after an alignment problem, these would be tightened. (6)

(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)

Discuss the causes, possible associated hazards and lowering of thermal efficiency consequent on poor combustion in a Diesel engine cylinder. Illustrate your answer by means of indicator cards. (16)

Explain how the following condition effect the power developed by a diesel

(a) Broken piston rings. (4)

(b) Worn fuel pump plungers. (4)

(c) Fouled turbochargers. (4)

(d) Worn out liner. (4)

(a) Explain the advantages of fitting highly rated medium speed engines with double exhaust and air inlet valves. (6)

(b) State the disadvantages of double valve arrangements. (4)

(c) Explain the possible causes of persistent burning of exhaust valves if it is:

(i) General to most cylinders. (3)

(ii) Specific to a single cylinder. (3)

With reference to the diesel prime movers for generators in unmanned machinery spaces:

(a) Outline the monitoring and control equipment designed to protect the engine. (8)

(b) Describe the methods employed to test the monitoring and control equipment, during a routine check. (8)

(a) What are the causes of Turbocharger surging? How is it indicated to the watchkeeper? (8)

(b) What are the possible remedial action? (4)

(c) What are the reasons for excessive fouling of the turbocharger? (4)

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaf deflection. (16)

Sketch and describe the operation of a crankcase oil mist detector. What operational maintenance does this instrument require for efficient performance. (16)

(a) With the help of simple diagram, explain Variable Injection Timing (VIT). (8)

(b) Explain with suitable diagram, start and end of VIT points. (4)

(c) Explain with a sketch the variation of P(Max) with VIT position. (4)

(a) What do you understand by Specific fuel consumption? Give some examples of SFOC for a two stroke engine and the auxiliary engines. (6)

(b) Explain the terms: (i) flash point, (ii) pour point, (iii) calorific value, (iv) CCAI value, (v) octane number and (vi) cetene number (12)

Compare the desirable qualities of the lubricating oil selected for each of the following duties:

(a) Auxiliary diesel engines (4)

(b) Stern tube bearings (4)

(c) Refrigeration compressors (4)

(d) Gear case of purifier (4)

Give reason for the differing properties of the oils recommended for these four purposes (4)

Explain how the following condition effect the power developed by a diesel engine:

(a) Broken piston rings. (4)

(b) Worn fuel pump plungers. (4)

(c) Fouled turbochargers. (4)

(d) Worn out liner. (4)

(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 meaures that can be taken to reduce the impact of poor bunker quality. (6)

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

(b) Discuss the various factors affecting the failures of crankshafts in marine diesel engines. (6)

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 any engine may fail to turnover on air. (8)

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 H.P. suction valve and excessive H.P. clearance volume. (16)

(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)

(a) Explain the types of turbocharging in a marine diesel engine. (8)

(b) What are the reasons that may induce vibration on a main engine turbocharger? (8)

(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)

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

(a) State the different types of turbo chargers fitted on modern diesel engines. (8)

(b) Describe the function of the following: (8)

(i) nozzle ring,

(ii) labyrinth seals,

(iii) diffuser, and

(iv) inducer

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

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.

(a) Describe what is nozzle burning of Fuel Injectors and causes of nozzle burning on marine Diesel engine. (6)

(b) What investigations are required to find causes for nozzle burning? (6)

(c) What actions are required to reduce the risk of Nozzle Burning? (4)

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.

(a) Sketch and describe the Starting air system of main engine. (8)

(b) What are the safety interlocks provided in compressed air Starting system of Main Engine? (8)

Explain how sluggish action of the suction and delivery valves reduces the volumetric efficiency of an air compressor. (16)

Make a report to the Chief Engineer of your vessel about malfunctioning of low lub oil pressure alarm for the auxiliary engine, observed during your watch, with special emphasis on the possible consequences. (16)

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

(a) In reference to a Starting air system of main engine, explain the function of the air start distributor? (8)

(b) What should be the sequence of action to be initiated if the Automatic air starting valve malfunctions during manoeuvring? (8)

(a) Draw sectional diagram of main engine piston showing each part. Show cooling passages for oil cooled piston (12)

(b) Name the differnt materials used for the various components of the piston as indicated to the answer above. (4)

(a) Explain, why is it important to measure bearing clearances in a diesel engine? (4)

(b) What is Bridge gauge? How is the Bridge gauge used? Explain with a diagram. (6)

(c) What are other recommended methods for checking bearing clearances. (6)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Piston Stroke (4)

(b) Swept Volume (4)

(c) Clearance volume (4)

(d) Compression ratio (4)

(a) What is a Exhaust Gas Economizer? Draw diagrammatic Sketch of Exhaust gas Economizer (EGE) naming each component. (8)

(b) How is steam Generation controlled in Exhaust Gas Economizers? (4)

(c) Briefly describe procedure to maintain efficiency of such an E.G.E. (4)

If an auxiliary diesel generator over speeds while off load, explain:

(a) How can the engine be stopped? (6)

(b) What are the probable reasons for the failure? (4)

(c) Give details of the checks that are required to be made after the engine has been stopped, with regard to (i) Mechanical checks and

(ii) Electrical checks (6)

(a) In a 4-Stroke engine, describe each of the different strokes of the cycle. (6)

(b) Draw 4-Stroke timing diagram describing the complete cycle. Explain how each stroke is completed with action of crank travel and the inlet-exhaust valves. (10)

(a) With a aid of a sketch briefly describe the important structural parts of 2-Stroke main Engine? How are different structural parts held together? (10)

(b) What is the function of Cross Head Guides? (6)

For 2-Stroke Marine Diesel Engine

(a) What are the desirable properties of crankcase lubricating oil? (6)

(b) Why magnetic filter is fitted on LO system and where is it fitted? (4)

(c) Which property of synthetic lubricants allows them to perform better than mineral oils under heavy loads and elevated marine engine temperatures? (6)

(a) Sketch a main engine jacket water cooling system (8)

(b) State why chemical treatment of such systems is necessary (4)

(c) What tests are carried out to ascertain the level of the concentration of the chemicals in the jacket cooling water system? (4)

(a) Describe with suitable sketches, how lubricating oil is conveyed to top end, bottom end and main bearings in a large bore slow speed engine. (10)

(b) List the causes leading to sudden loss of lubricating oil pressure in the engine. (6)

(a) What is function of Charge air cooler on 2-Stroke Diesel Engine? (4)

(b) Draw Diagrammatic Sketch of charge air cooler. Describe each part. (8)

(c) How the efficiency of charge air cooler can be checked? (4)

(a) Describe a pressure relief device fitted on a diesel engine crankcase. Are these devices fitted on all sizes of the engine? (8)

(b) What attention do crankcase pressure relief device require? (4)

(c) Name the factors which must be present for an explosion to occur in the crankcase of a diesel engine. (4)

(a) In modern electronic type 2 stroke main engines which components are replaced by electronic equivalents (8)

(b) Describe by drawing a simple sketch, fuel injection system on electronic type engine. (6)

(c) How fuel is injected at right moment in electronic type engine ? (2)

(a) Sketch and describe the significance of Chocks? Give the three different types of chocks fitted in marine diesel engines. Briefly describe the purpose of each. (8)

(b) What are the different classification of chocks based on its material? (4)

(c) What are resilient chocks? Where are these fitted and why? (4)

(a) Draw diagrammatic Sketch, describing each part of thrust block. (8)

(b) Describe how propeller thrust is transmitted to hull? (4)

(c) How to measure thrust clearances on the block? (4)

(a) Draw Lubricating oil piping diagram with all fittings for a trunk type 4-Stroke Diesel Engine (8)

(b) What properties are required for a Lubricating oil used in a 4-stroke Diesel engine? (4)

(c) What is the effect on lubricating oil due to various contaminants during operation of engine? (4)

With reference to engine inlet and exhaust valves:

(a) State why tappet clearance is essential and why it must be periodically checked. (6)

(b) List with reasons the likely consequences of excessive and insufficient tappet clearance. (4)

(c) State how carbon build-up can occur during engine running and indicate the possible effects on cylinder performance. (6)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Natural Aspiration. (4)

(b) Scavenging. (4)

(c) Supercharging. (4)

(d) Types of Super charging in two stroke engine. (4)

(a) State why double walled fuel pipes are employed for high pressure fuel lines. (6)

(b) Sketch and describe such a double walled pipe arrangement and show how high pressure pipe failure is indicated. (10)

(a) How power is calculated from indicator diagrams? (6)

(b) How does Indicator diagram show early fuel injection? What are effects of too early injection? (5)

(d) What are indications of late Injection on indicator diagram of the unit? What are bad effects of late injection of fuel on the units? (5)

With reference to a turbo-charging system of an engine:

(a) State the parameters that you would check while taking over the watch. (8)

(b) Action to be taken in the event of turbo charger is observed to vibrate abnormally. (8)

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaft deflection. (16)

(a) Describe how fuel injector components deteriorate with time? (6)

(b) What are effects of deterioration of fuel injector components? (6)

(c) What are the signs of a bad injector? (4)

With respect to marine applications:

(a) What are the different types of lubrication system that you would see on the main and auxiliary machineries? (8)

(b) What are the desirable qualities for the lubricating oil selected for each of the following duties: (8)

(i) auxiliary diesel engine

(ii) stern tube bearings

(iii) refrigeration system

(iv) turbocharger

With reference to cylinder liner wear in large slow speed engine:

(a) State THREE major factors associated with wear. (4)

(b) Explain the procedure for correct 'running in' of piston rings and cylinder liners.

(c) Explain what is achieved by 'running in' process.

(d) Describe how cylinder lubrication limits wear.

Describe the action you as watch keeper would take and outline possible reasons for failure in both the following cases:

(a) The auxiliary diesel engine fails to turn on starting air, (8)

(b) The engine turn on starting air but fails to fire. (8)

A very sudden rise in pressure during combustion accompanied by a metallic, hammer like sound is called knocking of the unit or detonation and usually occurs (16)

(a) Near the end of the pressure rise after ignition of fuel charge

(b) Just before the fuel charge is about to ignite

(c) Immediately after the unit reaches peak pressure and before ignition of fuel

(d) At any stage of the combustion process.

State the correct answer and explain why the other reasons given are not justified.

(a) List and explain the desirable properties of lubricating oil for different application such as for main engine, auxiliary engine and for cylinder lubrication. (8)

(b) Sketch an auxiliary engine lubricating oil circuit. (8)

With reference to turbochargers:

(a) Explain the term surging, stating how it occurs, its effect on the turbocharger and how it can be avoided. (8)

(b) Describe the procedures for cleaning EACH of the following and explain the precautions which should be taken:

(i) Suction air

(ii) Turbine blades and nozzle ring (8)

Write short notes on:

(a) control air dryer (4)

(b) crankcase door (4)

(c) auxiliary engine overspeed trip (4)

(d) fuel oil leak off alarm (4)

A large marine diesel main propulsion engine, speed fluctuates all the time during the voyage. Make written statements to the chief engineer explaining the observation and various engine parameters during the voyage which could be indication of some fault, causing engine speed fluctuation. (16)

(a) What are the advantages of a thin shell bearing? (4)

(b) What are the typical bearing failures? Discuss at least four bearing failures. (8)

(c) Why is periodic analysis of the lubricating oil important? (4)

(a) Why tie-rods are provided on a 2-stroke main engine? (6)

(b) Why is a rod are placed close to the centerline of the crankshaft? (5)

(c) What is a tie rod punch screw? And what is its purpose? (5)

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

Name the stresses and justify by stating how they originate. (16)

Indicator cards have shown that one cylinder is high in power although the maximum pressure is low. State the associated effects that this might have on the various instruments of the engine and give a detailed description of the method of rectifying the defect. If this abnormality were not remedied, what might be the subsequent effects on the operation of the engine? State the type of engine to which your answer refers. (16)

Explain the method of obtaining the following diagrams on a 2- Stroke Main propulsion Engine:

(a) Power card, showing vital point of diagram. (4)

(b) Out of phase diagram, indicating vital points. (4)

(c) Light Spring Diagram, indicating vital points. (4)

(d) Compression diagram and its importance. (4)

(a) With reference to crankshafts and piston crowns, outline the main stresses to which these parts are subjected (4)

(b) In each case explain how the stresses are generated and how they vary in magnitude and direction during one cycle. (6)

(c) With respect to the whole engine describe how stresses may be accommodated by good design and influenced by poor maintenance. (6)

(a) What is crankshaft misalignment? (4)

(b) What are the reasons for crankshaft misalignment? (8)

(c) What is the effect on main engine of such misalignment? (4)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Natural Aspiration. (4)

(b) Scavenging. (4)

(c) Types of Super charging in two stroke engine. (4)

(d) Supercharging. (4)

(a) Sketch and describe a fuel oil system of a large diesel engine, from settling tanks to main engine fuel injectors. (10)

(b) Also, comment on the importance of

(i) Heating arrangement with temperature control (3)

(ii) Prevention of air lock in the system (3)

(a) How is a 2-Stroke engine started? Describe the sequence of engine starting. (6)

(b) Draw Timing Diagram of engine starting, showing crank position of each step. (6)

(c) What is OVERLAP in engine starting. (4)

With reference to the construction of a turbocharger, sketch and describe:

(a) The rotor bearing and its method of lubrication. (6)

(b) Labyrinth seal and explain how such a seal works. (6)

(c) Impeller and diffuser. (4)

(a) Draw sectional diagram of exhaust valve of 2 Stroke Diesel Engine. Name the different components of the valve. (8)

(b) Describe working of the valve in operation. How valve rotation occurs during operation and its purpose. (6)

(c) What is the special material used on valve lid. (2)

(a) What are the difficulties observed in lubrication of gear teeth in gear trains? (4)

(b) Describe with diagram, how good lubrication to gear teeth is achieved? (6)

(c) What are the qualities of Lubricating oil suitable for main Reduction Gearing of main engine? (6)

An auxiliary engine under load continuously fluctuates even with a steady load. The fault you diagnose could be owing to

(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 decarbonisation

Give a brief explanation as to why each of the above mentioned points either could be true or cannot at all be the reason for such a fluctuation. (16)

(a) With reference to a 2 stroke slow speed main propulsion engine, sketch a line diagram showing the air starting system. (8)

(b) State, with reasons, three safety features incorporated in an air starting system. (3)

(c) State with reason why an engine may fail to turnover on air. (5)

Discuss the precautions, which can be taken to minimize the possibility of a diesel engine crank case explosion and the transmission of dangerous flame into the machinery space.

(a) by design and equipment (8)

(b) by operating personnel (8)

(a) What are the causes of Turbocharger surging? How is it indicated to the watchkeeper? (8)

(b) What are the possible remedial action? (4)

(c) What are the reasons for excessive fouling of the turbocharger ? (4)

With reference to the diesel prime movers for generators in unmanned machinery spaces:

(a) Outline the monitoring and control equipment designed to protect the engine. (8)

(b) Describe the methods employed to test the monitoring and control equipment, during a routine check. (8)

With reference to medium speed trunk piston engines:

(a) explain the purpose of an anti-polishing ring. (5)

(b) Describe how effective piston cooling is provided. (5)

(c) where is the thrust bearing fitted and why? (6)

(a) Sketch a section through the bedplate and A frame of a large slow speed engine, identifying parts, method of construction and materials. (10)

(b) Explain the function of the tie bolts and how after an alignment problem, these would be tightened. (6)

(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)

(c) State the materials used for the seat and valve described in (a) (4)

Discuss the causes, possible associated hazards and lowering of thermal efficiency consequent on poor combustion in a Diesel engine cylinder. Illustrate your answer by means of indicator cards. (16)

The main requirements which a fuel injection system must fulfil are

(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 wether each of the points made above are true or false with reasons (16)

(a) Explain the advantages of fitting highly rated medium speed engines with double exhaust and air inlet valves. (6)

(b) State the disadvantages of double valve arrangements. (4)

(c) Explain the possible causes of persistent burning of exhaust valves if it is:

(i) General to most cylinders. (3)

(ii) Specific to a single cylinder. (3)

Make a report to the Chief Engineer of your vessel about malfunctioning of low lub oil pressure alarm for the auxiliary engine observed during your watch, with special emphasis on the possible consequences. (16)

(a) State the different types of turbo charger fitted in modern diesel engines. (8)

(b) Describe the function of the (8)

(i) nozzle ring,

(ii) labyrinth seals,

(iii) diffuser, and

(iv) inducer.

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaft deflection. (16)

Sketch and describe the operation of a crankcase oil mist detector. What operational maintenance does this instrument require for efficient performance. (16)

(a) With the help of simple diagram, explain Variable Injection Timing (VIT). (8)

(b) Explain with suitable diagram, start and end of VIT points (4)

(c) Explain with a sketch the variation of Pmax with VIT position. (4)

(a) What do you understand by Specific fuel consumption? Give some examples of SFOC for a two stroke engine and the auxiliary engines. (4)

(b) Explain the terms: (12)

(i) flash point,

(ii) pour point,

(iii) calorific value,

(iv) CCAI value,

(v) octane number and

(vi) cetene number.

(a) Compare the desirable qualities of the lubricating oil selected for each of the following duties: (16)

(i) Auxiliary diesel engines,

(ii) Stern tube bearings,

(iii) Refrigeration compressors

(iv) Gear case of purifier

Give reason for the differing properties of the oils recommended for these four purposes.

(a) Explain the types of turbocharging in a marine diesel engine. (8)

(b) What are the reasons that may induce vibration on a main engine crankshaft? (8)

Explain how sluggish action of the suction and delivery valves reduces the volumetric efficiency of an air compressor. (16)

During your watch one of the main engine unit was indicating high exhaust temperature reading. Write a note to Chief Engineer explaining:

(a) the probable cause of the abnormal running condition and how it was diagnosed (8)

(b) list the possible corrective actions (8)

(a) What is the significance of an air cooler and why is the scavenge air temperature preferred to be maintained at 40°C? (8)

(b) What are the probable indications of a leaky air cooler as fitted to a two stroke main engine? (8)

The maritime decarbonization is a priority and there are various ships that are operating on alternative fuels. Discuss few potential alternate fuels by comparing their properties and list the advantages & disadvantages of at least three alternative fuels. (16)

Write short notes on:

(a) Main air starting valves (4)

(b) Exhaust valve rotator (4)

(c) Scavenge relief valve (4)

(d) Function of Labyrinth Seals in turbocharger (4)

Make a diagrammatic sketch of a jacket cooling water system as applied to a two stroke main engine. Indicate the temperature and pressure in the system. Describe in particular the flow of water from entry to the engine to outlet from the engine and sketch the more important joints in the system (16)

Write short notes on the following:

(a) Indicated Power (3)

(b) Specific fuel oil consumption (3)

(c) Brake power (3)

(d) Mechanical efficiency (3)

(e) Thermal efficiency (4)

Write Short notes on the following:

(a) Effect of worn out rings on oil consumption and blow by (5)

(b) Cylinder liner wears. (6)

(c) Thermal loading of piston. (5)

(a) Sketch a main engine jacket water cooling system (8)

(b) State why chemical treatment of such systems is necessary (4)

(c) What tests are carried out to ascertain the level of the concentration of the chemicals in the jacket cooling water system? (4)

(a) Describe with suitable sketches, how lubricating oil is conveyed to top end, bottom end and main bearings in a large bore slow speed engine. (10)

(b) List the causes leading to sudden loss of lubricating oil pressure in the engine. (6)

(a) What is function of Charge air cooler on 2-Stroke Diesel Engine? (4)

(b) Draw Diagrammatic Sketch of charge air cooler. Describe each part. (8)

(c) How the efficiency of charge air cooler can be checked? (4)

(a) Describe a pressure relief device fitted on a diesel engine crankcase. Are these devices fitted on all sizes of the engine? (8)

(b) What attention do crankcase pressure relief device require? (4)

(c) Name the factors which must be present for an explosion to occur in the crankcase of a diesel engine. (4)

(a) In modern electronic type 2 stroke main engines which components are replaced by electronic equivalents. (8)

(b) Describe by drawing a simple sketch, fuel injection system on electronic type engine. (6)

(c) How fuel is injected at right moment in electronic type engine? (2)

(a) Sketch and describe the significance of Chocks ? Give the three different types of chocks fitted in marine diesel engines. Briefly describe the purpose of each. (8)

(b) What are the different classification of chocks based on its material? (4)

(c) What are resilient chocks? Where are these fitted and why? (4)

(a) Draw diagrammatic Sketch, describing each part of thrust block. (8)

(b) Describe how propeller thrust is transmitted to hull? (4)

(c) How to measure thrust clearances on the block? (4)

(a) Draw Lubricating oil piping diagram with all fittings for a trunk type 4-Stroke Diesel Engine. (8)

(b) What properties are required for a Lubricating oil used in a 4-stroke Diesel engine? (4)

(c) What is the effect on lubricating oil due to various contaminants during operation of engine? (4)

With reference to engine inlet and exhaust valves:

(a) State why tappet clearance is essential and why it must be periodically checked. (6)

(b) List with reasons the likely consequences of excessive and insufficient tappet clearance. (4)

(c) State how carbon build-up can occur during engine running and indicate the possible effects on cylinder performance. (6)

(a) Sketch and describe the Starting air system of main engine. (8)

(b) What are the safety interlocks provided in compressed air Starting system of Main Engine? (8)

(a) Draw sectional diagram of main engine piston showing each part. Show cooling passages for oil cooled piston (12)

(b) Name the different materials used for the various components of the piston as indicated to the answer above. (4)

(a) Explain, why is it important to measure bearing clearances in a diesel engine? (4)

(b) What is Bridge gauge? How is the Bridge gauge used? Explain with a diagram. (6)

(c) What are other recommended methods for checking bearing clearances? (6)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Piston Stroke (4)

(b) Swept Volume (4)

(c) Clearance volume (4)

(d) Compression ratio (4)

(a) What is a Exhaust Gas Economizer? Draw diagrammatic Sketch of Exhaust gas Economizer (EGE) naming each component. (8)

(b) How is steam Generation controlled in Exhaust Gas Economizers? (4)

(c) Briefly describe procedure to maintain efficiency of such an E.G.E. (4)

If an auxiliary diesel generator over speeds while off load, explain:

(a) How can the engine be stopped? (6)

(b) What are the probable reasons for the failure? (4)

(c) Give details of the checks that are required to be made after the engine has been stopped, with regard to (6)

(i) Mechanical checks and,

(ii) Electrical checks

(a) In a 4-Stroke engine, describe each of the different strokes of the cycle. (6)

(b) Draw 4-Stroke timing diagram describing the complete cycle.

Explain how each stroke is completed with action of crank travel and the inlet-exhaust valves. (10)

(a) With a aid of a sketch briefly describe the important structural parts of 2-Stroke main Engine? How are different structural parts held together? (10)

(b) What is the function of Cross Head Guides? (6)

For 2-Stroke Marine Diesel Engine

(a) Describe problems in achieving good lubrication of Cylinder Liner. (6)

(b) What are the properties of good cylinder oil? (4)

(c) What are the consequences of under and over lubrication of liner? (6)

The main requirements which a fuel injection system must fulfil are

(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

Analyse each of the above statements and State whether they are true or false with a brief reasoning. (16)

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)

(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)

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 decarbonisation

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.

(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)

(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)

(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

Explain briefly how the different moving parts of a main engine are subjected to various stresses. Name the stresses and justify by stating how they originate. (16)

(a) Describe the procedure for taking crankshaft deflections, 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)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Natural Aspiration. (4)

(b) Scavenging. (4)

(c) Supercharging. (4)

(d) Types of Super charging in two stroke engine. (4)

(a) State why double walled fuel pipes are employed for high pressure fuel lines. (6)

(b) Sketch and describe such a double walled pipe arrangement and show how high pressure pipe failure is indicated. (10)

(a) How power is calculated from Indicator diagrams.? (6)

(b) How does Indicator diagram show early fuel injection?

What are effects of too early injection? (5)

(c) What are indications of late Injection on indicator diagram of the unit?

What are bad effects of late injection of fuel on the units? (5)

With reference to a turbo-charging system of an engine:

(a) State the parameters that you would check while taking over the watch. (8)

(b) Action to be taken in the event of turbo-charger is observed to vibrate abnormally. (8)

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaft deflection (16)

(a) Describe how fuel injector components deteriorate with time? (6)

(b) What are effects of deterioration of fuel injector components? (6)

(c) What are the signs of a bad injector? (4)

With respect to marine applications:

(a) What are the different types of lubrication system that you would see on the main and auxiliary machineries? (8)

(b) What are the desirable qualities for the lubricating oil selected for each of the following duties: (8)

(i) auxiliary diesel engine

(ii) stern tube bearings

(iii) refrigeration system

(iv) turbocharger

With reference to cylinder liner wear in large slow speed engine.

(a) State THREE major factors associated with wear. (4)

(b) Explain the procedure for correct 'running in' of piston rings and cylinder liners. (4)

(c) Explain what is achieved by 'running in' process. (4)

(d) Describe how cylinder lubrication limits wear. (4)

Describe the action you as watch keeper would take and outline possible reasons for failure in both the following cases:

(a) The auxiliary diesel engine fails to turn on starting air. (8)

(b) The engine turn on starting air but fails to fire. (8)

A very sudden rise in pressure during combustion accompanied by a metallic hammer like sound is called knocking of the unit or detonation and usually occurs: (16)

(a) Near the end of the pressure rise after ignition of fuel charge

(b) Just before the fuel charge is about to ignite

(c) Immediately after the unit reaches peak pressure and before ignition of fuel

(d) At any stage of the combustion process.

State the correct answer and explain why the other reasons given are not justified.

(a) List and explain the desirable properties of lubricating oil for different application such as for main engine, auxiliary engine and for cylinder lubrication. (8)

(b) Sketch an auxiliary engine lubricating oil circuit. (8)

With reference to turbochargers:

(a) Explain the term surging, stating how it occurs, its effect on the turbocharger and how it can be avoided. (8)

(b) Describe the procedures for cleaning EACH of the following and explain the precautions which should be taken: (8)

(i) Suction air

(ii) Turbine blades and nozzle ring

Write short notes on:

(a) Control air dryer (4)

(b) Crankcase door (4)

(c) Auxiliary engine overspeed trip (4)

(d) Fuel oil leak off alarm (4)

A large marine diesel main propulsion engines, speed fluctuates all the time during the voyage. Make written statements to explain the observation of various engine parameters during the voyage which could be indication of some fault, causing engine speed fluctuation.

(a) What are the advantages of a thin shell bearing? (4)

(b) What are the typical bearing failures? Discuss at least four bearing failures. (8)

(c) Why is periodic analysis of the lubricating oil important? (4)

(a) Why tie-rods are provided on a 2-stroke main engine? (6)

(b) Why tie rods are placed close to the centerline of the crankshaft? (5)

(c) What is a tie rod pinch screw? And what is its purpose? (5)

(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)

Indicator cards have shown that one cylinder is high in power although the maximum pressures is low. State the associated effects that this might have on the instruments of the engine and give a detailed description of the method of rectifying the defect. If this abnormality were not remedied, what might be the subsequent effects on the operation of the engine? State the type of engine to which your answer refers. (16)

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.

(a) In a 4-Stroke engine, describe each of the four strokes of the engine. (5)

(b) Draw timing diagram of a complete cycle. (5)

(c) How each stroke is completed, in the engine with action of crank travel and valves. (6)

(a) Describe means of recognizing deterioration of the lubricating oil. (8)

(b) Describe how lubrication oil is conveyed to top end, bottom end and main bearings in large bore, 2 stroke cross head type slow speed diesel engine, you are familiar with (8)

(a) State the different types of turbo charger fitted in modern diesel engines. (8)

(b) Describe the function of the (8)

(i) nozzle ring,

(ii) labyrinth seals,

(iii) diffuser, and

(iv) inducer

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

(a) What is the importance of measuring bearing clearance in a diesel engine. (4)

(b) What is Bridge gauge?. Describe it's usage with diagram. (6)

(c) What are the other recommended methods used onboard to check bearing clearances. (6)

(a) Describe what is nozzle burning of Fuel injectors and causes of nozzle burning on marine Diesel engine. (6)

(b) What investigations are required to find causes for nozzle burning? (6)

(c) What actions are required to reduce the risk of Nozzle Burning? (4)

Explain how the following condition effect the power developed by a diesel engine:

(a) Broken piston rings. (4)

(b) Worn fuel pump plungers. (4)

(c) Fouled turbochargers. (4)

(d) Worn out liner. (4)

For 2-Stroke Marine Diesel Engine

(a) Describe problems in achieving good lubrication of Cylinder Liner. (6)

(b) What are the properties of good cylinder oil? (4)

(c) What are the consequences of under and over lubrication of liner? (6)

Efficient smooth combustion depends upon some or all of the following:

(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. (16)

(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)

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

(b) Discuss the various factors affecting the failures of crankshafts in marine diesel engines. (6)

(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)

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 H.P. suction valve and excessive H.P. clearance volume. (16)

(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)

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

(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)

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

An auxiliary engine under load continuously fluctuates even with a steady load.

The fault you diagnose could be owing to

(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 decarbonisation

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. (16)

(a) With reference to a 2 stroke slow speed main propulsion engine, sketch a line diagram showing the air starting system (8)

(b) State, with reasons, three safety features incorporated in an air starting system. (3)

(c) State with reason why an engine may fail to turnover on air. (5)

Discuss the precautions, which can be taken to minimize the possibility of a diesel engine crank case explosion and the transmission of dangerous flame into the machinery space.

(a) By design and equipment (8)

(b) By operating personnel (8)

(a) What are the causes of Turbocharger surging? How is it indicated to the watchkeeper? (8)

(b) What are the possible remedial action? (4)

(c) What are the reasons for excessive fouling of the turbocharger? (4)

With reference to the diesel prime movers for generators in unmanned machinery spaces:

(a) Outline the monitoring and control equipment designed to protect the engine. (8)

(b) Describe the methods employed to test the monitoring and control equipment, during a routine check. (8)

With reference to medium speed trunk piston engines:

(a) Explain the purpose of an anti-polishing ring (5)

(b) Describe how effective piston cooling is provided; (5)

(c) Where is the thrust bearing fitted and why? (6)

(a) Sketch a section through the bedplate and A frame of a large slow speed engine, identifying parts, method of construction and materials. (10)

(b) Explain the function of the tie bolts and how after an alignment problem, these would be tightened. (6)

(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)

Discuss the causes, possible associated hazards and lowering of thermal efficiency consequent on poor combustion in a Diesel engine cylinder. Illustrate your answer by means of indicator cards. (16)

The main requirements which a fuel injection system must fulfil are

(a) Accurate metering of small amount of fuel oil

(b) Control of quality of fuel injection

(c) Proper timing of the fuel injection

(d) Effective distribution of the fuel in the combustion space

State whether each one of the points made above are true or false with reasons. (16)

(a) Explain the advantages of fitting highly rated medium speed engines with double exhaust and air inlet valves. (6)

(b) State the disadvantages of double valve arrangements. (4)

(c) Explain the possible causes of persistent burning of exhaust valves if it is:

(i) General to most cylinders. (3)

(ii) Specific to a single cylinder. (3)

Make a report to the Chief Engineer of your vessel about malfunctioning of low lube oil pressure alarm for the auxiliary engines, observed during your watch, with special emphasis on the possible consequences. (16)

(a) State the different types of turbo charger fitted in modern diesel engines. (8)

(b) Describe the function of the (8)

(i) Nozzle ring,

(ii) Labyrinth seals,

(iii) Diffuser, and

(iv) Inducer

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaft deflection. (16)

Sketch and describe the operation of a crankcase oil mist detector. What operational maintenance does this instrument require for efficient performance. (16)

(a) With the help of simple diagram, explain Variable Injection Timing (VIT). (8)

(b) Explain with suitable diagram, start and end of VIT points. (4)

(c) Explain with a sketch the variation of P(Max) with VIT position. (4)

(a) What do you understand by Specific fuel consumption? Give some examples of SFOC for a two stroke engine and the auxiliary engines. (6)

(b) Explain the terms: (12)

(i) Flash point,

(ii) Pour point,

(iii) Calorific value,

(iv) CCAI value,

(v) Octane number and

(vi) Cetene number

Compare the desirable qualities of the lubricating oil selected for each of the following duties: (16)

(a) Auxiliary diesel engines

(b) Stern tube bearings

(c) Refrigeration compressors

(d) Gear case of purifier

Give reason for the differing properties of the oils recommended for these four purposes

Explain the method of obtaining the following diagrams on a 2-Stroke Main propulsion Engine:

(a) Power Card, showing vital point of diagram. (4)

(b) Out of Phase diagram indicating vital points. (4)

(c) Light Spring Diagram, Indicating vital points (4)

(d) Compression diagram and its importance (4)

(a) With reference to crankshafts and piston crowns, outline the main stresses to which these parts are subjected. (4)

(b) In each case explain how the stresses are generated and how they vary in magnitude and direction during one cycle (6)

(c) With respect to the whole engine describe how stresses may be accommodated by good design and influenced by poor maintenance. (6)

(a) What is crankshaft misalignment? (4)

(b) What are the reasons for crankshaft misalignment? (8)

(c) What is the effect on main engine of such misalignment? (4)

(a) During your watch one of the main engine units was indicating high exhaust temperature reading. Write a note to Chief Engineer explaining how the cause leading to abnormal running condition was diagnosed (8)

(b) Subsequent action taken to control the situation. (8)

(a) Sketch and describe a fuel oil system of a large diesel engine, from settling tanks to main engine fuel injectors. (10)

(b) Also comment on the importance of

(i) Heating arrangement with temperature control (3)

(ii) Prevention of air lock in the system (3)

(a) How is a 2-Stroke engine started? Describe the sequence of engine starting. (6)

(b) Draw Timing Diagram of engine starting, showing crank position of each step. (6)

(c) What is OVERLAP in engine starting. (4)

With reference to the construction of a turbocharger, sketch and describe:

(a) The rotor bearing and its method of lubrication (6)

(b) Labyrinth seal and explain how such a seal works. (6)

(c) Impeller and diffuser (4)

(a) Draw sectional diagram of exhaust valve of 2-Stroke Diesel Engine. Name the different components of the valve. (8)

(b) Describe working of the valve in operation. How valve rotation occurs during operation and its purpose. (6)

(c) What is the special material used on valve lid. (2)

(a) What are the difficulties observed in lubrication of gear teeth in gear trains? (4)

(b) Describe with diagram, how good lubrication to gear teeth is achieved? (6)

(c) What are the qualities of Lubricating oil suitable for main Reduction Gearing of main engine? (6)

(a) Sketch and describe the Starting air system of main engine. (8)

(b) What are the safety interlocks provided in compressed air Starting system of Main Engine? (8)

(a) Draw sectional diagram of main engine piston showing each part. Show cooling passages for oil cooled piston (12)

(b) Name the different materials used for the various components of the piston as indicated to the answer above. (4)

(a) Explain, why is it important to measure bearing clearances in a diesel engine? (4)

(b) What is Bridge gauge? How is the Bridge gauge used? Explain with a diagram. (6)

(c) What are other recommended methods for checking bearing clearances. (6)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Piston Stroke (4)

(b) Swept Volume (4)

(c) Clearance volume (4)

(d) Compression ratio (4)

(a) What is a Exhaust Gas Economizer? Draw diagrammatic Sketch of Exhaust gas Economizer(EGE) naming each component. (8)

(b) How is steam Generation controlled in Exhaust Gas Economizers? (4)

(c) Briefly describe procedure to maintain efficiency of such an E.G.E. (4)

If an auxiliary diesel generator over speeds while off load, explain:

(a) How can the engine be stopped? (6)

(b) What are the probable reasons for the failure? (4)

(c) Give details of the checks that are required to be made after the engine has been stopped, with regard to: (6)

(i) Mechanical checks and;

(ii) Electrical checks

(a) In a 4-Stroke engine, describe each of the different strokes of the cycle. (6)

(b) Draw 4-Stroke timing diagram describing the complete cycle.

Explain how each stroke is completed with action of crank travel and the inlet-exhaust valves. (10)

(a) With a aid of a sketch briefly describe the important structural parts of 2-Stroke main Engine? How are different structural parts held together? (10)

(b) What is the function of Cross Head Guides? (6)

For 2-Stroke Marine Diesel Engine

(a) Describe problems in achieving good lubrication of Cylinder Liner (6)

(b) What are the properties of good cylinder oil? (4)

(c) What are the consequences of under and over lubrication of liner? (6)

(a) Sketch a main engine jacket water cooling system (8)

(b) State why chemical treatment of such systems is necessary (4)

(c) What tests are carried out to ascertain the level of the concentration of the chemicals in the jacket cooling water system? (4)

(a) Describe with suitable sketches, how lubricating oil is conveyed to top end, bottom end and main bearings in a large bore slow speed engine.

(b) List the causes leading to sudden loss of lubricating oil pressure in the engine.

(a) What is function of Charge air cooler on 2-Stroke Diesel Engine? (4)

(b) Draw Diagrammatic Sketch of charge air cooler. Describe each part. (8)

(c) How the efficiency of charge air cooler can be checked? (4)

(a) Describe a pressure relief device fitted on a diesel engine crankcase. Are these devices fitted on all sizes of the engine? (8)

(b) What attention do crankcase pressure relief device require? (4)

(c) Name the factors which must be present for an explosion to occur in the crankcase of a diesel engine. (4)

(a) In modern electronic type 2 stroke main engines which components are replaced by electronic equivalents. (8)

(b) Describe by drawing a simple sketch. fuel injection system on electronic type engines (6)

(c) How fuel is injected at right moment in electronic type engine? (2)

(a) Sketch and describe the significance of Chocks. Give the three different types of chocks fitted in marine diesel engines. Briefly describe the purpose of each. (8)

(b) What are the different classification of chocks based on its material? (4)

(c) What are resilient chocks? Where are these fitted and why? (4)

(a) Draw diagrammatic Sketch, describing each part of thrust block (8)

(b) Describe how propeller thrust is transmitted to hull? (4)

(c) How to measure thrust clearances on the block? (4)

(a) Draw Lubricating oil piping diagram with all fittings for a trunk type 4-Stroke

Diesel Engine. (8)

(b) What properties are required for a Lubricating oil used in a 4-stroke Diesel engine? (4)

(c) What is the effect on lubricating oil due to various contaminants during operation of engine? (4)

With reference to engine inlet and exhaust valves:

(a) State why tappet clearance is essential and why it must be periodically checked. (6)

(b) List with reasons the likely consequences of excessive and insufficient tappet clearance. (4)

(c) State how carbon build-up can occur during engine running and indicate the possible effects on cylinder performance. (6)

The main requirements which a fuel injection system must fulfil are

(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

Analyse each of the above statements and State whether they are true or false with a brief reasoning. (16)

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)

(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)

An auxiliary engine under load continuously fluctuates even with a steady load. The fault you diagnose could be owing to:

(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 decarbonisation

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. (16)

(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)

(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)

(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

Explain briefly how the different moving parts of a main engine are subjected to various stresses. Name the stresses and justify by stating how they originate. (16)

(a) Describe the procedure for taking crankshaft deflections, 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)

A very sudden rise in pressure during combustion accompanied by a metallic hammer like sound is called knocking of the unit or detonation and usually ocours (16)

(a) Near the end of the pressure rise after ignition of fuel charge

(b) Just before the fuel charge is about to ignite

(c) Immediately after the unit reaches peak pressure and before ignition of fuel

(d) At any stage of the combustion process.

State the correct answer and explain why the other reasons given are not justified

(a) List and explain the desirable properties of lubricating oil for different application such as for main engine, auxiliary engine and for cyliner lubrication (8)

(b) Sketch an auxiliary engine lubricating oil circuit.

With reference to turbochargers:

(a) Explain the term surging, stating how it occurs, its effect on the turbocharger and how it can be avoided (8)

(b) Describe the procedures for cleaning EACH of the following and explain the precautions which should be taken: (8)

(i) Suction air

(ii) Turbine blades and nozzle ring

Write short notes on:

(a) Control air dryer (4)

(b) Crankcase door (4)

(c) Auxiliary engine overspeed trip (4)

(d) Fuel oil leak off alarm (4)

A large marine diesel main propulsion engines, speed fluctuates all the time during the voyage. Make written statements to the chief engineer explaining the observation of various engine parameters, during the voyage which could be indication of some fault, causing engine speed fluctuation. (16)

(a) What are the advantages of a thin shell bearing? (4)

(b) What are the typical bearing failures? Discuss at least four bearing failures. (8)

(c) Why is periodic analysis of the lubricating oil important? (4)

(a) Why tie-rods are provided on a 2-stroke main engine? (6)

(b) Why tie rods are placed close to the centerline of the crankshaft? (5)

(c) What is a tie rod pinch screw? And what is its purpose? (5)

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

Name the stresses and justify by stating how they originate. (16)

Indicator cards have shown that one cylinder is high in power although the maximum pressure is low. State the associated effects that this might have on the various instruments of the engine and give a detailed description of the method of rectifying the defect. If this abnormality were not remedied, what might be the subsequent effects on the operation of the engine? State the type of engine to which your answer refers. (16)

Describe following terms with respect to Diesel Engine with suitable diagram:

(a) Natural Aspiration. (4)

(b) Scavenging. (4)

(c) Supercharging. (4)

(d) Types of Super charging in two stroke engine. (4)

(a) State why double walled fuel pipes are employed for high pressure fuel lines. (6)

(b) Sketch and describe such a double walled pipe arrangement and show how high pressure pipe failure is indicated. (10)

(a) How power is calculated from Indicator diagrams? (6)

(b) How does Indicator diagram show early fuel injection?

What are effects of too early injection? (5)

(c) What are indications of late Injection on indicator diagram of the unit?

What are bad effects of late injection of fuel on the units? (5)

With reference to a turbo-charging system of an engine :

(a) State the parameters that you would check while taking over the watch. (8)

(b) Action to be taken in the event of turbo-charger is observed to vibrate abnormally. (8)

Discuss the consequences of failure to maintain correct clearances in the case of auxiliary diesel engine crankshaft and bottom end bearings. Describe the procedure of taking crankshaft deflection. (16)

(a) Describe how fuel injector components deteriorate with time? (6)

(b) What are effects of deterioration of fuel injector components? (6)

(c) What are the signs of a bad injector? (4)

With respect to a marine diesel engine:

(a) What are the different types of lubrication system that you would see on the main and auxiliary machineries? (8)

(b) What are the desirable qualities for the lubricating oil selected for each of the following duties: (8)

(i) Auxiliary diesel engine

(ii) Stern tube bearings

(iii) Refrigeration system

(iv) Turbocharger

With reference to cylinder liner wear in large slow speed engine.

(a) State THREE major factors associated with wear. (4)

(b) Explain the procedure for correct 'running in' of piston rings and cylinder liners. (4)

(c) Explain what is achieved by 'running in' process. (4)

(d) Describe how cylinder lubrication limits wear. (4)

Describe the action you as watch keeper would take and outline possible reasons for failure in both the following cases:

(a) The auxiliary diesel engine fails to turn on starting air (8)

(b) The engine turn on starting air but fails to fire. (8)

The main requirements which a fuel Injection systen must fulfil are:

(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. (16)

(a) In a 4-Stroke engine, deseribe each of the four strokes of the engine. (5)

(b) Draw timing diagram of a complete cycle. (5)

(c) How each stroke is completed, in the engine with action of crank travel and valves. (5)

(a) Describe means of recognizing deterioration of the lubricating oil. (8)

(b) Describe how lubrication oil is conveyed to top end, bottom end and main bearings in large bore, 2 stroke cross head type slow speed diesel engine, you are familiar with (8)

(a) State the different types of turbo charger fitted in modern diesel engines (8)

(b) Describe the function of the: (8)

(i) Nozzle ring.

(i) Labyrinth seals.

(in) Diffuser. and

(iv) Inducer

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

(a) What is the importance of measuring bearing clearance in a diesel engine (4)

(b) What is Bridge gauge? Describe it's usage withs diagram (6)

(c) What are the other recommended methods used onboard in check bearing clearances (6)

(a) Describe what is nozzle burning of Fuel Injectors and causes of nozzle burning on marine Diesel engine. (6)

(b) What investigations are required to find causes for nozzle burning? (6)

(c) What actions are required to reduce the risk of Nozzle Burning? (4)

Explain how the following condition effect the power developed by a diesel engine:

(a) Broken piston rings. (4)

(b) Worn fuel pump plungers. (4)

(c) Fouled turbochargers. (4)

(d) Worn out liner. (4)

For 2-Stroke Marine Diesel Engine

(a) Describe problems in achieving good lubrication of Cylinder Liner. (6)

(b) What are the properties of good cylinder oil? (4)

(c) What are the consequences of under and over lubrication of liner? (6)