Motor Engineering – MEO CLASS 4 MMD PAPER

SECTION 2

1. While an auxiliary boiler is operating at design load, which of the following actions will occur if the automatic combustion control system detects a steam pressure drop?
   1. More burners will be lighted off.
   2. The registers will open fully.
   3. The fuel oil valve and air damper will open wider.
   4. The steam flow will be automatically regulated.

ANS.: C                                    

2. A unit type fuel injector is used on a diesel engine to ___________.
   1. meter the fuel
   2. produce the proper fuel oil pressure
   3. atomize the fuel
   4. all of the above

ANS.: D

3. With the help of explanatory sketches briefly state the lubrication system for a large 2 stroke slow speed marine diesel engine for the following.
   1. camshaft bearings
   2. main bearings
   3. piston crosshead bearings
   4. cylinder walls

ANS.: C

4. If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will _____________.
   1. open late and close early
   2. open late and close late
   3. fail to open when the engine is cold
   4. fail to open at normal operating temperature

ANS.: A

5. Regarding a Diesel engine crankcase, the general arrangement and installation should preclude the possibility of
   1. free entry of air to the crankcase
   2. water entering the crankcase while engine washdowns are being performed            
   3. excessive oil leakage during periods of increased blowby
   4. subcooling internal components

ANS.: A

6. The growth rate of microbiological organisms as found in some fuel supplies will __________.
   1. increase in direct proportion to an increase in temperature
   2. decrease if bleaches are added to the fuel on a regular basis
   3. remain unchanged provided complete consumption of the fuel occurs monthly
   4. All of the above

ANS.: A                                                                                                                              

7. Fuel injection pumps using the port and helix metering principle requires the use of a ___________.
   1. crosshatched design
   2. lapped plunger and barrel
   3. variable stroke
   4. variable cam lift

ANS.: B      

8. Internal combustion engine crankcase vent outlets must be equipped with ______.
   1. hinged rain guards
   2. corrosion resistant flame screens            
   3. dipsticks for measuring oil levels
   4. crankcase ventilation fans

ANS.: B

9. Proper lubrication of the main bearings is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because ____________.       
   1. bearing pressure in a four-stroke/cycle single acting diesel engine is continually reversed
   2. bearing pressure in a two-stroke/cycle single acting diesel engine is continually reversed
   3. the maximum bearing pressure is higher in a single acting two-stroke/cycle diesel engine
   4. two-stroke/cycle diesel engines require more complicated lubrication piping            : A

9. Increasing the valve clearance between a valve stem and rocker arm, will result in the valve _____________.
   1. closing later
   2. opening sooner
   3. staying open for a shorter period of time
   4. staying open for a longer period of time

ANS.: C

11. What preventative maintenance should be done frequently to diesel engine starting air receivers?
    1. Drain the accumulated moisture.
    2. Test the relief valves.
    3. Watch the temperature to prevent fluctuations in pressure.
    4. Clean the interior to remove oil and foreign matter.

ANS.: A

12. Friction developing between the moving parts of a governor, governor linkage and control valve will cause the governor to _________.
    1. react with insufficient speed droop
    2. fail to react to small speed changes
    3. have excessive sensitivity to small speed changes
    4. remain in the neutral position

ANS.: B

13. To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of _____________.
    1. brass
    2. copper
    3. iron
    4. monel metal or stainless steel

ANS.: D

14. In a diesel engine, maximum lube oil system pressure is normally controlled by
    1. the capacity of the lube oil pump
    2. the speed of the lube oil pump
    3. the outlet pressure of the lube oil pump
    4. a relief valve

ANS.: D

15. Which of the following statements describes the function of an expansion tank in a diesel engine cooling system?
    1. Maintains a constant head on the system.
    2. Reduces the likelihood of air or steam pockets formation.
    3. Provides a low pressure point for the addition of makeup cooling water.
    4. All of the above.

ANS.: D

16. Within the cycle of a forced circulation auxiliary water-tube boiler, part of the water flashes into steam, and the remaining hot water is ___________.
    1. collected in the lower portion of the steam accumulator for recirculation back to the heating coil or water tank
    2. returned to the lower drum via downcomers due to density difference for reheating
    3. passes through the domestic heating system return line steam traps to the auxiliary feed supply tank
    4. automatically dumped into auxiliary feed heater and reheated by auxiliary exhaust back pressure

ANS.: A

17. Ignition failure in an automatically controlled auxiliary boiler could be caused by _____________.
    1. carbon deposits on the flame scanner
    2. high fuel oil temperature
    3. low fuel oil viscosity
    4. high steam pressure

ANS.: A

18. Which of the fuel injection systems listed uses a spring loaded differential spray needle valve and an individual pump for each cylinder?
    1. Common-rail injection
    2. Air injection
    3. Jerk pump injection
    4. Distributor injection

ANS.: C

19. The interior of some diesel engine saltwater heat exchangers are protected from corrosion by the use of __________.
    1. aluminum plates
    2. lead cathodes
    3. copper baffle plates
    4. sacrificial zincs

ANS.: D

20. The amount of chloride content in the water of an auxiliary boiler can be reduced by ____________.
    1. adding hydrazine
    2. blowing down the boiler
    3. adding phenolphthalein
    4. adding a sulfite chloride scavenger

ANS.: B

21. Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type pump with a concentric housing to ____________.
    1. provide cooling water flow when the engine is running either ahead or astern
    2. provide the greatest pump efficiency
    3. prevent pump clogging from marine growth
    4. prevent cavitation at the pump outlet

ANS.: A

22. The lube oil cooler is located after the lube oil filter in order for _____________.
    1. the filter to operate more efficiently
    2. the lube oil cooler to be bypassed
    3. positive lube oil pump suction to be assured
    4. galvanic action in the cooler to be minimized

ANS.: A

23. A very sudden rise in pressure during combustion accompanied by knocking of the unit or detonation  usually occurs
    1. Near the end of the pressure rise after ignition of fuel charge.
    2. Just before the fuel charge is about to ignite.
    3. Immediately after the unit reaches peak pressure and before ignition of fuel charge.
    4. At any stage of the combustion process.

ANS.: A

24. The main requirements which a fuel injection system must fulfill are and state each one of the points made above are true or false
    1. accurate metering of small amount of fuel oil.
    2. control of quality of fuel injection
    3. proper timing of the fuel injection
    4. selective distribution of the fuel in the combustion space.

. Ans : A, B, C (TRUE)  and D (FALSE)

25. In any marine diesel engine, air movements inside a combustion chamber is very important. Generally speaking, air movement helps, State which of the above points are true or false
    1. to distribute the fuel
    2. to mix it with air
    3. to cool the cylinder liner
    4. to help in optimising liner lubrication
    5. to assist combustion
    6. to reduce after burning
    7. to reduce combustion temperatures.

Ans : All true

26. Sacrificial zinc anodes are used on the saltwater side of diesel engine heat exchangers to _____________.
    1. reduce electrolytic action on heat exchanger metals
    2. keep heat transfer surfaces shiny and clean
    3. prevent rapid accumulation of marine growth
    4. provide a protective coating on heat exchanger surfaces

ANS.: A

27. The fuel supply system to an automatic auxiliary boiler, will be automatically shutdown if the boiler _____________.
    1. salinity is abnormally high
    2. steam demand is too high
    3. water level is abnormally low
    4. feed water flow is low

ANS.: C

28. The crankcases of many diesel engines are kept under a slight vacuum to _____________.
    1. improve fuel economy
    2. increase the air charge velocity
    3. reduce the risk of explosion
    4. all of the above

ANS.: C

29. The rate of cylinder lubricating oil metered to each cylinder of a large, low-speed, main propulsion diesel  engine is ______________.                              
    1. the same, whether at sea, or during maneuvering
    2. adjusted during each hour of operation while at constant RPM
    3. higher at sea than while maneuvering
    4. lower at sea than while maneuvering

ANS.: C

30. On a medium-speed main propulsion diesel engine, the crankpin or crank journal bearings receive lubricating oil from                            
    1. a spindle lubricator
    2. an oil jet
    3. internal splashing
    4. drilled passages in the crankshaft

ANS.: D