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30 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is meant by the power stroke? |
The stroke of the piston caused by the expansion of gases and is also known as the working stroke |
1 mark |
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What is a cycle? |
A series of events repeated in a regular order to bring about the efficient operation of the engine |
1 mark |
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How do cylinders get their fuel oil for ignition? |
By having the fuel oil sprayed into them By pumps |
2 marks |
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What is meant by valve timing? |
The adjustment of valves to open or close at the proper time for the efficient operation of the engine |
1 mark |
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What is meant by supercharging? |
Increasing the amount of charge air in the working cylinder |
1 mark |
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What is the purpose of scavenging in the engine cylinder? |
To remove combustion products and supply fresh air to the cylinder |
1 mark |
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What is the function of the oil control ring? |
To remove excess sludge To control the amount of oil on the cylinder wall |
2 marks |
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Name an advantage and disadvantage of fitting dry liners |
Adv - cheap, light construction, no external corrosion of parts Dis - can deform on installation, no easy access to cooling passages for cleaning |
2 marks |
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Name 1 advantage and 1 disadvantage of fitting wet liners |
Advantage Easy removal with special tools Good access to cooling passages More efficient cooling through direct contact Disadvantage Heavy construction More expensive Leakage can occur past 'O" rings causing water contamination of the lub oil |
2 marks |
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What are 5 causes of internal cylinder wear? |
Friction Corrosion Ring flutter Abrasives Poor lubrication |
5 marks |
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What are the effects of valve clearances too small? |
Valves open early close late Loss of power Loss of efficiency Loss of compression |
2 marks |
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What are 2 effects of valve clearances too large? |
Valves open late close early Loss of power Loss of efficiency Black smoke |
2 marks |
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What causes bent push rods? |
Overspeed Incorrect valve clearances previously set |
2 marks |
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Give 2 reasons why crackshaft deflections should be checked? |
Replacement of bearings Replacing engine mounts Uneven water of bearings |
2 marks |
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What are the requirements for a crankcase explosion |
Flammable vapour within the explosive range A localised hotspot to produce ignition |
2 marks |
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What sources of hotspots can cause crankcase explosions? |
Perforated piston crown Piston blow by Incipient component seizure Main bearing failure Distortion of engine seating |
3 marks |
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What are 3 lub tests carried out on board? |
Water content fresh/salt water Carbonaceous content TBN Viscosity |
3 marks |
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What are the purposes of the fuel injection pump? |
Boost fuel pressure sufficient to open the injector Vary the quantity of fuel delivered Inject the fuel at precisely the right moment Deliver equal amount of fuel to the injectors Control engine speed and power |
5 marks |
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3 major components of the fuel injection pump? |
Barrel and plunger Delivery valve and seat Cam shaft |
3 marks |
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What are 3 symptoms of injector nozzle problems? |
Knock in 1 or more cylinder Engine overheating Loss of power Black or Smokey exhaust Increased fuel consumption |
3 marks |
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State the meaning of viscosity |
The body or thickness of a fluid and it’s resistance to flow Measured over a controlled distance at a set temperature and time |
1 mark |
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State 2 reasons for using additives in lub oil |
Increase of temperature range Detergent Multi-grade Rust inhibitor Resist oxidation |
2 marks |
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State the meaning of flashpoint |
The point at which a fluid gives off sufficient vapour within the explosive range and if a source of ignition was present explosion may occur |
4 marks |
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List 4 types of oil systems |
Wet sump Dry sump Splash lubricated Forced lubrication Spray lubrication |
4 marks |
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What is the importance of oil testing? What are we testing for? |
To detect early, developing faults in machinery Spot test Water content fresh/salt Dilution of the oil Viscosity of the oil |
5 marks |
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Why is it necessary to carry out periodical maintenance? |
To check condition of the engine To identify anything that may need attention Too make sure engine still confirms to manufacturer’s specifications |
3 marks |
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What is the purpose of the vibration dampener? Where is it usually located? |
Used to reduce rotational vibrations caused by the crankshaft Located on the non drive end of the crankshaft |
3 marks |
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Why are multi-stage and sequential turbos used? |
Higher effectiveness of the plant Improved specific fuel usage Reduced toxic exhaust gases Reduced exhaust temperatures |
4 marks |
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What are the effects of? Cylinder liner bottom ring seal failure Lub oil cooler internal failure Cylinder head crack |
Contamination of the sump Contamination of both the lub oil by freshwater and the coolant by the oil Water in the combustion chamber |
3 marks |
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How can you measure fuel consumption? |
Dipping tanks Tank level indicators Flow meters |
3 marks |
