1. In case of 2-stroke marine diesel engines, the top
part of the liner forming the combustion chamber experiences very high pressure
induced mechanical stresses as well as high thermal stresses. Which of the
following is a correctly designed liner for catering both the above stresses ?
\
A. Thick top portion with jacket cooling to take care of
both the high mechanical and thermal stresses
B. Thick top portion to take care of high mechanical
stresses while bore cooling to reduce thermal gradients
C.Thin top portion to reduce thermal gradients and hence
thermal stresses while supporting ribs to take care of mechanical stresses
D. Thick top portion to take care of high mechanical
stresses with jacket cooling combined with allowance for thermal expansion to
minimize the thermal stresses
ANS B
2 In a direct connected or geared main propulsion
diesel engine would be fitted with a:
A. Isochronous hunting governor
B. Rotating governor disc
C. Variable speed govener
D. Constant frequency governor
ANS C
3) The light and medium fuels utilized in internal
combustion engines provide a source of
a)lubrication for pistons and rings
b)food for microbiological organisms
c)gases most detrimental to the ozone layer of the
atmosphere
d)all of the above
ANS B
4. 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
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 charge.
d) At any stage of the combustion process.
5)
Which of the following functions is done by a cam operating an exhaust valve ?
A.It
governs the timing of opening and closing of the valve .
B.It
governs the speed at which the valve operates
C.It
governs the amount of opening of the valve
D.All
of the above
ANS D
6.
In modern marine 2-stroke diesel engines, ________________ is sometimes used as
a coating on the underside of the exhaust valve disc, to reduce the rate of hot
corrosion.
A.Monel
B.Chromium
C.Inconel
D.Cermet
7.
when m/e is running in emergency condition which of the alarms can't be
bypassed
1.LO
low pressure
2.jacket water high temp
3.piston
cooling water high temp
4.all
the above
ANS
A
8 What to check if Engine is not taking load.?
a.
Water tightness to be checked.
b.
Air to be removed from jacket water outlet line.
c.
Priming lube oil pump to run before starting the engine.
d.
Check the lube oil level.
e.
Check the flow of lube oil.
f.
Blow through the engine before starting
9 An auxiliary engine turbo-charger makes strange noises when the load changes.
The engine parameters however are absolutely fine. An external examination of
turbocharger parameters as stated in the manual also reveals nothing. Would you
a)
continue to run the engine and wait for some time
b)
stop the engine for a while and make some checks
c)
reduce the load of the engine
d)
run it on steady load to make some checks.
ANS
A OR C
10 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.
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