Marine engineering knowledge for Class 4B MMD exam
A large marine diesel main propulsion engines, speed
fluctuates all the time during the voyage. Give a report (in about 200 words)
to the chief engineer explaining the observation of various engine parameters,
during the voyage which could be indication of some fault, causing engine speed
Sketch an auxiliary engine starting air system,
naming the various components, and fittings in the system.
rise in pressure during combustion accompanied by knocking of the unit or detonation usually occurs
the pressure rise after ignition of fuel charge.
fuel charge is about to ignite.
the unit reaches peak pressure and before ignition of fuel charge.
the combustion process.
requirements which a fuel injection system must fulfil are
of small amount of fuel oil.
of fuel injection
the fuel injection
distribution of the fuel in the combustion space.
true or false. If any point you perceive is false, state why is it so.
diesel engine, air movements inside a combustion chamber is very important.
Generally speaking, air movement helps
optimising liner lubrication
false. If any point you perceive is false, state why is it so.
engine under load continuously fluctuates even with a steady load. The fault
you diagnose could be owing to
servicing of the governor in the last port.
fuel injectors done in the last decarbonisation
inspection undertaken with respect to the main Diesel engines during a one-day
stoppage at a foreign port after a long period of continuous running.
emergency fire pump simply refuses to start after running perfectly for a period of half an hour just before you
prepare it to restart again. State just 4 checks you would make to confirm the
cause of this problem.
manifold of an emergency generator engine under load turns red hot. There is no
lagging on the manifold. What efforts would you make to cool down the manifold?
State clearly what could be the causes for such an occurrence.
Explain the possible reasons
for excessive lubricating oil consumption in an auxiliary Diesel engine and
state the danger, which may be associated with this defect.
Prepare a notice for the engine room support staff
stating 10 points of caution while working in enclosed space.
Sketch and describe Turbo charger end bearings of any
make you know off, complete with its housing and lubrication arrangement.
What is meant by combustion noise and mechanical noise.
How are each generated and measured. Give four typical values of noise
measurement in different parts of the engine room.
Write Short notes on the following:
Effect of worn out rings on oil consumption and blow by
Dry liners and wet liners
Thermal loading of piston.
Sacrificial zinc anodes are used on the saltwater side
of diesel engine heat exchangers to _____________.
electrolytic action on heat exchanger metals
heat transfer surfaces shiny and clean
rapid accumulation of marine growth
a protective coating on heat exchanger surfaces
The fuel supply system to an automatic auxiliary
boiler, will be automatically shutdown if the boiler ______________.
is abnormally high
demand is too high
level is abnormally low
flow is low
The crankcases of many diesel engines are kept under a
slight vacuum to _____________.
the air charge velocity
the risk of explosion
of the above
The rate of cylinder lubricating oil metered to each cylinder of a large, low-speed, main propulsion
diesel engine is ______________.
same, whether at sea, or during maneuvering
during each hour of operation while at
at sea than while maneuvering
at sea than while maneuvering
On a medium-speed main propulsion diesel engine, the
crankpin or crank journal bearings receive lubricating oil from _____________.
passages in the crankshaft
are installed on the generating tube surfaces in waste heat boilers to
soot fires in the exhaust system
exhaust gas erosion of the tubes
the velocity of exhaust gas flow
the rate of heat transfer
During your watch one of the main engine unit was
indicating high exhaust temperature reading. Write a note to Chief Engineer
how the cause leading to abnormal running condition was
subsequent action taken to control the fire.
FOUR operational conditions that may lead to vibration of the main transmission
are the main advantages of the impulse and the constant pressure exhaust
how sluggish action of the suction and delivery valves reduces the volumetric
efficiency of an air compressor.
detailed description of the tilting pad block. stating any important dimensions
respect of hydraulic ram type steering gear:
the emergency locking device that can be used in order to speedily bring the
steering gear to rest:
with one reason the best angular position to lock the steering gear in.
reading of the steam pressure gauge of an auxiliary boiler is suspect.
action to be taken
Sketch a cascade control system.
any diesel engine closed freshwater cooling system, the lowest pressure exists
at the _____________.
jacket water outlet
cooling water pump outlet
heat exchanger outlet
expansion tank atmospheric vent
main advantage of unit injectors over other fuel injection
systems is _____________.
Reducing the need of too many high pressure fuel lines
their relatively low injection pressures
reduced wear of spray orifices
the lessened chance of fuel leaks into the engine sump
up a notice on the Lube Oil Purifier, to keep a close eye on the Lube Oil level
on the sight glass, which is not giving a clear indication of the level owing
to the glass being damaged. Suggest some precautions in the notice.
would be indicated by ____________.
carbon on the register doors
a dazzling white atomizer flame
fluctuating pressure in the windbox
an unevenly shaped burner flame
Lubricating oil systems for diesel engine journal
bearings are usually lubricated by which of the following types of lubricating oil systems?
experience has shown persistent damage occurring on seating faces of main
engine exhaust valves which is not confined to any particular cylinder unit.
State, with reasons, the possible causes.
State the short-term action to be taken in order to
minimize engine operational problems.
a diagrammatic sketch of a jacket cooling water system as applied to a group of
medium speed auxiliary diesel engines. Indicate the temperatures and pressures
in the system. Describe in particular the flow of water from entry to the
engine to outlet from the engine and sketch the more important joints in the
block diagram describe the operation of an electronic governor fitted to an
auxiliary diesel engine.
Explain briefly how the different moving parts of a
main engine are subjected to various stresses.
justify by stating how they originate.
control valves, used in piston cooling water systems
State FOUR reasons for fitting a valve positioner;
Explain the operation of a positioner in control
than the pulse or constant pressure systems.
freshwater cooling system is at the _____________.
jacket water outlet
expansion tank inlet
heat exchanger inlet
cooling water pump outlet
instructions to the support crew for matters concerning safety during
watchkeeping related to rotating machinery parts.
Sketch and describe a main air starting valve
of any large two stroke marine diesel engine known to you.
Write short notes on :
of absorbing thrust of a 4 stroke auxiliary engine crankshaft
of large 2 stroke marine diesel engine drive gear / timing gear.
Cooling the intake air supplied to a diesel engine will
reduce mean effective pressure
decrease average compression pressure
decrease air charge density
increase power output
When there is a flame failure in an automatically fired
auxiliary boiler, the ____________.
air supply is shut off
fuel supply is shut off
water feed is shut off
safety valve lifts
Lubrication for the main reduction gears used with
diesel engines is usually supplied by _____________.
oil from the main engine sump
an independent lube oil system
the stern bearing head tank
the stern bearing sump tank
Which of the listed items should be secured before performing any maintenance on a solenoid operated
air start valve?
Lube oil standby pump
What is to be installed on an internal combustion
engine if its cylinder bore exceeds 200mm?
Crankcase vapor monitors
Engine exhaust silencers
Constant pressure type turbochargers
Explosion relief valves
Which of the following actions should normally be taken
during each watch when the auxiliary boiler is in operation?
Clean the flame scanner photocell window.
Inspect and clean all solenoid valves.
Lift the safety valves by hand.
Inspect for oil or water leaks.
vibration of an automatically fired auxiliary boiler can be caused by
air or water in the furnace
fuel oil pump failure