Certification Assistance for Marine Engineers
Canadian First Class ME
Engineering Knowledge - Motors (1)In Canada, Transport Canada administers the Marine Engineering examination process; visit the Training Page for details on the process. The actual exam consist of nine (9) questions randomly drawn from a question bank of the various subject. Six (only) must be answered in a 3.5hrs time frame. The exam questions are similar to these, presented below, and are drawn heavily from similar question in the Reed's Marine Engineering series of books.
Brought to you by www.dieselduck.net comments to [email protected]
Disclaimer
Transport Canada has ask us to advise users of this webpage to keep in mind that these questions are not the exact questions found in their exams. Martin's Marine Engineering Page - www.dieselduck.net is not affiliated with Transport Canada and these questions have been gathered from various sources.
Attempt any SIX (6) questions
Time = 3.5 hrs
TEST A
What is the calorific value of diesel fuel? Give the percentages of heat losses and for useful work. State methods of heat recovery.
Sketch and describe a direct-driven blower. What arrangements are made for astern running?
Discuss the purpose of purifying fuel oil. Sketch a two centrifuge fuel oil system including settling tanks. double bottom tanks, etc.What routine service is required of purifiers?
Explain isothermal, adiabatic and polytropic terms in a diesel engine air compressor. What are the practical limitations?
Explain how you would set the valve timing and fuel pump timing on a four�stroke diesel engine.
Describe the principles of operation and sequence of four-stroke and two�stroke cycle diesel engines. Give timing diagrams, degrees and make of engine.
Sketch and describe a diesel-electric propulsion system for a ship and state how the propeller shafting is reversed.
Sketch and describe the flywheel for a large diesel engine. State its purpose and indicate how it is fitted. State why a Flywheel can be made lighter on a large diesel engine.
Describe in detail the construction of any vertical boiler used for auxiliary service aboard a motor ship. Give details of all riveted joints with the aid of sketches.
TEST B
Sketch and describe the lubricating oil system of any diesel engine with which you are familiar with.
Sketch and describe a multi-stage Air-compressor, naming all parts. What possible dangerous conditions could occur?
Sketch and describe a diesel-electric propulsion system for a ship and state how the propeller shafting is reversed.
Describe a large 2-stroke opposed piston diesel engine, the advantages and dis-advantages of same.
What is the definition of a supercharger? Describe the different methods of supercharging a diesel engine, stating the advantages.
State the approximate calorific value of fuel oil. State the percentage of fuel utilized in the engine. State the various losses in percentage and describe how lost heat can be regained.
Describe how you would prepare a Scotch Marine Boiler for inspection and the possible defects you would look for.
Describe any type of hydraulic coupling, stating the type of fluid used in this coupling.
Describe how you would time a fuel pump for a diesel engine. Name the type of pump and describe how you would increase the fuel supply in this pump.
Test C.
Sketch and describe a fuel injection pump suitable for an airless injection diesel engine, (Bosch type). Describe fully how it operates and how the quantity of fuel is regulated. State the materials it is made of.
Explain why it is necessary to have intercoolers on a multi-stage compressor. what attention do these require to keep them in a good and safe working condition? Sketch and describe the construction of an intercooler suitable for a working pressure of 2400 kpa? State materials.
Sketch and describe a rotary lobe type blower suitable for supplying air to a large reversible diesel engine. Describe the means of controlling air when the engine is reversed.
With the aid of crankshaft timing diagrams, describe the sequence of events and the crankshaft angles for the following:
(a) four-stroke diesel engine
(b) two-stroke diesel engine
Also mention the make of engine referred to.
Describe how to take an indicator diagram and sketch a normal diagram for a two-stroke diesel engine. What information can be found from such a diagram? Also what is a �draw� card? Sketch a draw card for the above engine and explain its uses.
Sketch and describe a mechanism used to lubricate the cylinders of a diesel engine. How is the device isolated from the water cooling jacket? At what point is the oil injected; why and where? Give reasons for lubricating cylinders this way.
Sketch and describe any type of waste gas and oil-fired boiler used for auxiliary purposes. Show riveted joints and describe any stays used.
Sketch and describe a built-up crankshaft. What materials are used and what tests are carried out on these materials? What stresses are crankshafts subjected to?
By means of a suitable sketch, describe the reversing mechanism stating the sequence of events for a large diesel engine.
TEST D
What are the pressures and temperatures in a 4-stroke diesel engine running full speed at the following critical instances
(A). Air at the beginning of the compression stroke.
(B). Air at the end of compression.
(C). Burning gasses at the end of combustion period.
(D). Burning gasses at the end of expansion period.
(E). Gasses at exhaust valve outlet
Draw an indicator card for a 4-stroke diesel engine, showing pressures and temperatures at critical points. Show on duplicate cards by dotted lines, the effects of leaking piston rings, early fuel injection, and late fuel injection.
Explain how cylinder liners and heads develop cracks, stating the possible causes. What symptoms would indicate these cracks.
Sketch and describe a 3-stage air compressor. Why are intercoolers fitted? What qualities are required by air compressor lubricating oils? What dangers can arise from improper compressor lubrication?
Sketch and describe a water cooling system. Give inlet and outlet at jacket and piston. What are the disadvantages of sea water cooling?
Describe the causes and preventions of the following explosions:
(A) Starting Air Lines
(B) Air Compressors
(C) Main Engine Crankcases
(D) How each of these explosions can be prevented.
Sketch and describe a fuel pump suitable for solid injection type Main Diesel Engine. Describe the ahead and astern operation and control. Describe timing adjustment after overhaul.
Discuss port scavenging and valve scavenging. What is uniflow scavenging and how is it obtained?
What is boiler grooving? What causes it and how is it prevented? Describe a repair required on a grooving defect.
TEST E
State the necessary alterations required to convert a diesel engine to burn high viscosity bunker fuel from low viscosity fuel. State the advantages and dis-advantages of high viscosity fuel.
Describe a marine DC. propulsion system. How is the vessel�s speed controlled? How is it reversed and what are it�s advantages?
State the auxiliaries and their capacities on a typical marine propulsion diesel to insure the safe working of the ship. State the class and size of the vessel.
Describe how indicator cards are taken. How is the mean indicated pressure obtained? Sketch a 2-stroke and a 4-stroke indicator card.
Sketch and describe an engine driven rotary blower, showing how it is driven by the engine.
Describe by diagram an arrangement of two purifiers between fuel storage tank and fuel day tank, showing all pipes, valves, fittings, etc.
What is adiabatic compression and isothermal compression? Why is compression in a diesel engine adiabatic and why is it isothermal in a compressor?
Sketch and describe a vertical boiler. Show how shell seams are riveted. Show how various stays are fixed.
Describe:
(A) What is necessary in a diesel engine for good combustion.
(B) What causes:
Black Smoke?
White Smoke?
Blue Smoke?
(C) Give remedies for:
Black Smoke.
White Smoke.
Blue Smoke.
TEST F
Sketch and describe a tie bolt. How is it fitted in a large diesel engine and why? What type of engine does not require tie bolts and why?
Why does a 2-cycle engine need to be scavenged? Describe a reciprocating scavenge system. Why is the pump capacity larger than required?
State the advantages and dis-advantages of fresh water, sea water, and oil as a cooling media. What would happen if the temperature of each medium were permitted to rise to a high level?
Sketch and describe a high lift boiler safety valve. State the advantages of this type of valve over a regular safety valve.
What limits the power output of a diesel engine? How can the power be increased?
Describe two methods of reversing the direction of rotation of a diesel engine.
What would be the advantages of a 2-cycle diesel engine having a direct drive to the scavenge pump, or having an indirect driven rotary scavenge pump. Would there be any heat loss to the exhaust gasses?
Sketch and describe:
(A) an indicator card with normal compression and high firing pressure.
(B) what results would you expect?
(C) what would cause low compression?
(D) what would cause high compression?
Indicate what the air temperatures and pressures should be on a 4-cycle diesel engine:
(A) before compression.
(B) after compression
(C) after firing and combustion.
(D) exhaust gas leaving the cylinder.
TEST G
Sketch and describe a high pressure fuel pump. How does it operate on ahead and astern running? After overhaul, what timing does the pump require?
Write a report to an Engineer Superintendent or Ship Owner describing a defect you have found in a cylinder head. State the possible cause of the defect, method of repair, time taken and preventive measures, etc.
State the specific gravity, closed flash point and viscosity of good lubricating oil. Describe fully the lubricating system of a dry sump heavy oil engine.
Sketch and describe a pneumatically controlled air start system. If a valve stuck open how would you find the valve? What is overlap? Why is it necessary? How much overlap is required?
Sketch a Scotch Marine Boiler (3.65 m. Dia., 3 m long, with a working pressure of 1250 kPa.). Give all major sizes, shell and end plate thicknesses, stays, etc., and types of riveted joints.
State the stresses in a crosshead diesel engine and compare these to the stresses in a steam reciprocating engine.
What is the cause of scavenge fires and how do you deal with the situation? What can be done to prevent scavenge fires? Describe the effects of extinguishing systems using carbon dioxide or dry powder.
What are the effects of fuel in the crankcase of a diesel engine? How does the fuel get there? What do you learn from analyzed lube oil tests?
What is supercharging? What is meant to supply supercharged air? What are the effects of supercharging? Can a conventional diesel be converted to supercharging? State what would be required to carry out such a change.
TEST H
With the aid of sketches and diagrams, explain fully what is meant by combustion at constant volume and combustion at constant pressure. What type of engines use these methods?
Sketch and describe the construction of pistons suitable for a 4-stroke diesel engine and a 2-stroke diesel engine. Show each connecting rod is connected to the crosshead. How are the pistons cooled and lubricated? Indicate the type of engine to which the described piston would be fitted.
Why are the injection holes smaller in an engine with a 380 mm cylinder bore over an engine with a 760 mm cylinder bore? Since less fuel is required in the smaller bore engine why aren�t the number of holes reduced in the nozzle and the diameter of the holes remain the same in both nozzles?
What change, if any, takes place to exhaust gasses in an exhaust gas turbo-charger? Indicate the inlet and outlet temperatures and pressures on a turbo fitted to a large 4-stroke diesel engine.
Make a chart for recording wear measurement records of a cylinder liner. Show by sketch where these measurements would be taken. Indicate where the most wear would occur.
What is meant by the following terms:
(A) low speed heavy duty diesel engine.
(B) medium speed heavy duty diesel engine.
(C) high speed heavy duty diesel engine.
Indicate what would be the R.P.M. range of each. What are the advantages and disadvantages of each? What is the best use of each type of engine?
Describe the shop trial for a heavy oil engine. How are indicated and brake horse power calculated? How is the mechanical efficiency calculated? What would be the expected thermal efficiency? What would be the approximate fuel consumption per brake horsepower hour?
Sketch and describe a Bosch style fuel pump with a helix plunger. State the materials used in construction. Describe the pump�s operation and how it is driven.
Sketch and describe a flywheel for a heavy oil engine. Indicate it�s construction materials, purpose, and what determines it�s weight and how it�s weight may be reduced.
TEST I
Describe an electro-magnetic coupling as used in a diesel engine reduction gear. What is the advantage of reduction gearing.
Describe the action of any type of oil separator to which you are familiar. What is the difference in operation between a separator and a calorifier? Why is it desirable to preheat the oil? What is the purpose of fresh water priming of the separator?
Sketch and describe a cylinder liner for a large 2-stroke diesel engine. How is the liner tested during construction? How is it fitted to the cylinder block? How is it sealed to the cylinder block?
What are the effects of fuel in the crankcase of a diesel engine? How would fuel enter the crankcase? What is learned from analyzed oil samples?
Describe a 4-stroke diesel engine with a turbo charger. What is �overlap� and what is it�s function?
How would you measure the wear on a cylinder liner and a main bearing? What do these readings indicate and why are they taken? What would be the normal tolerances for wear?
With regard to compression ratios, what would be the result of increased final volumes in gasoline and diesel engines? Give compression temperatures and pressures.
Should be necessary to use salt water feed in a Scotch Marine Boiler, what density would you run the boiler at? How would you control the density? What effect would this have on the boiler? State the composition of salt water.
Sketch and describe an oily water separator for the removal of oil from bilge water. Why is this equipment essential?
TEST J
What would be the advantages of a 2-stroke diesel engine having a direct driven scavenge pump or an independently driven rotary pump? Would there be any heat loss to exhaust gasses?
Sketch and describe an indicator card with normal compression pressure and high firing pressure. What results would you expect to get? What would be the effect upon a cylinder with low compression pressure and high firing pressure?
Describe how a lead wire is used to find the clearance in a bottom end bearing but will not work for finding the top end clearance. Explain why leads are not taken at random crank pin angles. Describe the checks made to insure that there is adequate clearance for top and bottom end bearings.
Explain why fuel oil injector valve cooling is not always beneficial.
Describe how the following conditions affect the wear of piston rings and cylinder liners:
(A) ring pressure against the cylinder liner.
(B) contour of the ring edges.
(C) axial and radial depth of ring and groove.
(D) clearance of ring in ring groove.
In an automatically operated auxiliary boiler, describe the devices that allow automation. Describe why this boiler has safety fail safes. Describe the shut-down devices and methods of warning given.
Define �Critical Speed� as it applies to a diesel engine. What effect does a controllable pitch propeller have on the critical speed of an engine? What would happen to an engine if it were run at or near it�s critical speed for continuous periods of time.
Explain how and why suspended solids and carbon residue are said to affect the performance of a fuel injector.
How might the gasses in an enclosed crankcase, resulting from vaporization of the lubricating oil explode when (a) the engine is running, and (b) when the engine is at rest? Describe a crankcase safety device.
TEST K
Consider an engine fitted with a chain driven camshaft.
(i) What effect has the stretching of the chain upon engine performance and maintenance?
(ii) How is the chain tension adjusted to it�s initial value after stretching?
(iii)How is the engine timing corrected adjusting the chain?
(iv) What is the most common cause of chain failure and what part of the chain is most prone to this failure?
Give a considered and reasoned account for the types of failure to main engine turbo chargers listed below:
(i) a fractured turbine casing.
(ii) the rapid development of a severe problem of vibration.
(iii) the abrupt stopping of the turbo charger during normal operation accompanied by a great deal of noise.
Some modern motor ships have been fitted with electronic devices employing a cathode ray oscilloscope for obtaining indicator diagrams. The information from the cylinders of the prime mover can be displayed at a remote location, such for example, as the Chief Engineer�s office. Describe such a device and state the manner in which it may be used to illustrate certain important features, such as the combustion process, etc.
Discuss the merits and demerits of employing either a soluble oil or chromate solution as a corrosion inhibitor in the cooling system of a diesel engine.
What are the most influential physical characteristics required of the principle bearings for high speed, medium speed, and slow speed diesel engines? How do the following details relate to these characteristics?
(i) thin bearing shells
(ii) surface finish
(iii) fluid film lubrication
(iv) alignment
As Chief Engineer prepare a list of operating and maintenance procedures you would institute for the care of the main engines giving reasons each procedure and the trouble likely to arise from neglect of such procedures.
(i) Construct a line diagram for the complete starting air system for a main diesel engine.
(ii)Use sketches to help explain how starting, reversing, and stopping of the engine is accomplished.
(i) Discuss the principle forces a large diesel engine crankshaft must withstand while in service and how the stresses resulting from these forces are kept to acceptable limits by good design and operating criteria.
(ii)Discuss the manner in which the crankshaft may be over stressed and the difficulties arising there from.
(i) Discuss the factors contributing to the initiation and propagation of fires in the scavenge system of a diesel engine and the method of operation required to mitigate such an occurrence.
(ii)Discuss the use of (CO2) and dry powder as extinguishing agents.Brought to you by www.dieselduck.net comments to [email protected]
Disclaimer
Transport Canada has ask us to advise users of this webpage to keep in mind that these questions are not the exact questions found in their exams. Martin's Marine Engineering Page - www.dieselduck.net is not affiliated with Transport Canada and these questions have been gathered from various sources.