ME257 revision sheet 2 page 1

Question 1

The main components parts of governor

Answer 1

1. speed sensing unit
2. power piston unit
3. speed control unit

Question 2

State the procedure for testing mechanical overspeed trip

Answer 2

1. inform manoeuvring
2. run engine at normal temperatures at no load
3. increase engine speed, manually to 1380 RPM ( don’t exceed this speed or damage will occur )
4. check engine trips on mechanical overspeed between 1360 and 1380 RPM

Question 3

the function of the governor boost unit

Answer 3

pressurise the governor oil supply prior to start to be able to move fuel controls

Question 4

the major components on a mechanical overspeed device

Answer 4

1. trip unit “pop up” indicator
2. Baldwin control valves
3. the fuel limiters

Question 5

what must the governor be able to control/ accept

Answer 5

1. remove load
2. accept load
3. decrease speed by fuel rack
4. stop the engine
5. Start and increase speed by fuel rack

Question 6

state the purpose of the supercharger fluid coupling

Answer 6

1. Allows S/CH to run on after engine has stopped
2. Minimies effect of engine vibration S/CH
3. Reduces component inertia on start up

Question 7

list major components of submarine mechanical supercharger

Answer 7

sun wheel, annulus wheel, 3x plant wheels, fluid coupling, compressor

Question 8

state how the effect of low load running can be be reduced

Answer 8

use low sulpher fuel
maintain coolant and lube oil temps as high as possible
run at high load prior and after light load running

Question 9

list the components on a induction system

Answer 9

air filter, air trunking, induction manifold, turbo charger, supercharger, intercooler/ charge air cooler

Question 10

from what sources can water migrate into a diesel engine cylinder

Answer 10

1.operator error
2. coolant leaks
3. carbon build up on exhaust hull vv
4. defective exhaust hull vv

Question 11

maintenance checks carried out on the exhaust system

Answer 11

1. condition of fastenings
2. condition of lagging
3. check drain clear

Question 12

What defects are caused by excessive diesel exhaust back pressure

Answer 12

1.High exhaust temps
2. High coolant temp
3. High fuel consumption
4. Exhaust valve damage