NEW
Font size
WorksheetsMOTOR 18 Y 17
Total questions: 63
Worksheet time: 32mins
Air receivers installed in starting air systems are to be __________.
cylindrical in shape with service connections located at the top and bottom
opened and made available for inspection during biannual inspections
provided with automatic drain traps for the removal of moisture
so installed as to make the drain connections effective under extreme conditions of trim
To successfully reduce an excessively high diesel engine exhaust gas temperature, you should __________.
reduce the engine driven fuel pump outlet pressure
retard the fuel injector timing to reduce power
increase the fuel rack setting
reduce the load on the engine
High exhaust back pressure will result in an increase in __________.
turbocharger efficiency
engine power output
carbon deposits on fuel injectors
cylinder scavenging
The governor for an emergency diesel generator is shown in the illustration. When a large change in load results in a change in engine speed, which of the parts listed will be the FIRST governor component to react to the change in load?
Piece #8
Piece #9
Piece #13
Piece #21
A loop or cross scavenged engine utilizes the motion of its pistons and a turbocharger to provide scavenging air. Which of the listed mechanical designs prevents the air under the pistons from being pumped back through the scavenge ports during the piston power stroke?
Masked intake ports
Length of the piston skirt
Positive pressure from the blower
Lower liner seals
Which of the following statements concerning a closed type fuel injection nozzle is true?
The hole type of a closed nozzle is self-cleaning.
Multi-hole type nozzles are only suitable for use in engines with pre-combustion chambers.
Most closed nozzles open by fuel oil pressure acting on the differential area of the needle valve.
The pintle type nozzles are most susceptible to carbon deposits building up in and around the orifice.
The fuel injection pumps on a diesel engine are controlled by a linkage system attached to the __________.
camshaft
crankshaft
governor
flywheel
What type of fitting is to be used on diesel engine fuel injection line piping?
Mild steel
Hardened steel
Extra heavy
Double extra heavy
Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits, may cause __________.
low compression pressure
increased piston wear
increased cylinder lube oil consumption
poor contact between compression rings and liner
If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is __________.
a broken shaft on the freshwater pump
excessive fouling of the heat exchanger
an incorrect thermostatic element operating range
lube oil in the cooling water
Which of the following statements concerning the lubrication of diesel propulsion engines used in vessels over 300 gross tons is most accurate?
Lubrication systems using engine driven lube oil pumps do not require any additional independent arrangements when such arrangements have been proven reliable.
The use of engine driven pre-lube pumps is permitted on vessels with propulsion systems developing less than 500 shaft horsepower.
When forced lubrication is used for propulsion engines, one independently driven stand-by pump is to be provided in addition to the necessary pumps for normal operation.
Lubrication systems where two oil coolers are fitted require a minimum of two temperature control devices which may be actuated by similar sensors.
Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinder. If the cooling water temperature from all cylinders begins to rise above normal, you should suspect __________.
increased blow-by in all cylinders
incomplete combustion in all cylinders
overloading in all cylinders
insufficient fuel delivery to all cylinders
The torque transmitted by an electromagnetic induction coupling for an auxiliary diesel is dependent upon excitation and the __________.
engine speed
harmonic frequency
amount of slip
resonance
Some fuel injection systems utilize port-and-helix metering. Which of the following statement describes a system 'timed for port closing'?
Injection has a variable beginning and a constant ending.
Injection is metered by an external delivery valve.
Injection has a constant beginning and variable ending.
Injection will not occur until the helix closes the delivery valve.
Airflex clutches are used to transmit power from a diesel engine to the propeller shaft. A restricted orifice is used in the control air system of this unit to __________.
delay deflation of the clutch being disengaged
delay inflation of the clutch being engaged
reduce the deflation time of both clutches
reduce the inflation time of both clutches
Misalignment of the drive shaft and propeller shaft flanges can be detected by using a dial indicator or __________.
inside micrometer
feeler gage
adjustable trammel
sighting device
Where one or more diesel driven AC generators are operating in parallel, reducing the value of the speed droop to 'zero' on one unit will allow that unit to __________.
gradually reduce its speed as load is applied
change load without changing speed
automatically divide and balance the loads
effectively anticipate the amount of fuel necessary to bring the engine up to the proper output to accept the increased load
Antifreeze solutions containing ethylene glycol, should not be mixed with corrosion protection oils, as the resultant mixture __________.
is dangerously flammable
promotes scale buildup
may cause frothing
has a higher chloride content
The camshaft drive is designed to maintain proper camshaft speed relative to crankshaft speed. In maintaining this relationship, the camshaft drive causes the camshaft to rotate at __________.
one-half crankshaft speed in a two-stroke cycle diesel engine
crankshaft speed in a two-stroke cycle diesel engine
two times crankshaft speed in a two-stroke cycle diesel engine
one-fourth times crankshaft speed in a four-stroke cycle diesel engine
A three-way thermostatic control valve regulates the diesel engine cooling water temperature by passing a portion of the water __________.
around the engine
around the cooler
to the expansion tank
overboard
What is to be installed on an internal combustion engine if its cylinder bore exceeds eight inches?
Crankcase vapor monitors
Engine exhaust silencers
Constant pressure type turbochargers
Explosion relief valves
Which of the fuel systems listed combines the injection pump and the injection nozzle in one housing?
Common rail
Unit injector
Air injection
Hydraulic governing
Maintaining the lowest possible scavenging air temperature at all times is not recommended due to the possibility of the __________.
air charge density becoming too high
piston crown surfaces becoming too cold
formation of excessive quantities of condensate
compression pressure being greatly reduced
Most type(s) of microbiological growths in fuel are __________.
bacteria
fungi
yeasts
All of the above
On most modern diesel engines, the main and connecting rod bearings receive their lubricating oil by __________.
banjo feed
splash feed
gravity feed
pressure feed
When accumulated carbon at the air inlet ports of a two-stroke/cycle diesel engine is being removed, you should take care to avoid carbon __________.
entering the cylinder
particles becoming lodged under the intake valves
entering the water jacket
particles entering lube oil
A unit type fuel injector is used on a diesel engine to __________.
meter the fuel
produce the proper fuel oil pressure
atomize the fuel
all of the above
If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will __________.
open late and close early
open late and close late
fail to open when the engine is cold
fail to open at normal operating temperature
Regarding a diesel engine crankcase, the general arrangement and installation should preclude the possibility of __________.
free entry of air to the crankcase
water entering the crankcase while engine wash downs are being performed
excessive oil leakage during periods of increased blow by
sub cooling internal components
The growth rate of microbiological organisms as found in some fuel supplies will __________.
increase in direct proportion to an increase in temperature
decrease if bleaches are added to the fuel on a regular basis
remain unchanged provided complete consumption of the fuel occurs monthly
All of the above
Which of the fuel injection systems listed uses a spring loaded differential spray needle valve and an individual pump for each cylinder?
Common-rail injection
Air injection
Jerk pump injection
Distributor injection
What function is provided by the crankcase ventilation system on some diesel engines?
Increases the sludge forming tendency of lube oil.
Prevents the accumulation of combustible gases.
Improves lube oil cooling.
Improves cold weather starting.
Lubricating oil is supplied to the crankpin bearings in a marine diesel engine by __________.
internal crankshaft passages
immersion in oil
splash lubrication
injection lubrication
Sacrificial zinc anodes are used on the saltwater side of diesel engine heat exchangers to __________.
reduce electrolytic action on heat exchanger metals
keep heat transfer surfaces shiny and clean
prevent rapid accumulation of marine growth
provide a protective coating on heat exchanger surfaces
During the fuel injection period, fuel pressure must exceed cylinder gas pressure to __________.
ensure penetration and distribution of the fuel in the combustion chamber
ensure the needle valve is flushed clean during each injection
allow combustion gas blowback into the open needle valve
prevent reflected pressure waves when the needle valve closes
The overspeeding of the diesel engine driving an electric generator could cause __________.
low voltage trip to trip
reverse power trip to trip
damage to the field windings
excessive exhaust temperatures
An increase in the air inlet manifold pressure of a diesel engine will result in a/an __________.
decrease in maximum cylinder pressure
increase in ignition lag
decrease in fuel consumption per horsepower-hour
decrease in exhaust manifold pressure
The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and __________.
reduce water temperature
reduce water turbulence
provide an air cushion
allow for an increase in water volume as the engine warms up
Why are heavy fuels not usually prone to the problems of microbiological infection?
Heavy fuels are subjected to better refining processes which prevent the formation of these growths.
Most heavy fuels contain chemicals which prevent the growth of fungi and other bacteria.
Microbiological infection does not affect marine fuel but rather the personnel who are involved with the handling, storage and purification of the fuel.
The necessary nutrients that the organisms feed on are in a more complex form and not available for microbial degradation.
One method of constructing large marine diesel engines and reducing the total engine frame weight is through __________.
casting interlocking components
welding plates to form sections for assembly
forging integral components
case hardening integral components
Which of the following statements is true concerning a main diesel engine oil cooler?
The oil temperature is less than the cooling water temperature.
The oil pressure is less than the cooling water pressure.
The oil pressure is greater than the cooling water pressure.
The oil flow control valve is always installed in the oil input line.
The device allowing for the change in volume of the cooling water in a propulsion diesel engine closed cooling system is the __________.
fresh water expansion tank
sea water expansion tank
thermostatic expansion valve
jacket water cooler accumulator
Scavenging in a four-stroke/cycle diesel engine occurs during the __________.
last part of the exhaust stroke, and the first part of the intake stroke
last part of the intake stroke only
early part of the injection stroke only
early part of the power stroke
Diesel engine main and connecting rod precision bearings are made in halves. Each half exceeds one-half the bearing circumference by a small amount. The small amount is termed __________.
clearance
crush
pitch
thrust
The piston rod scraper box incorporated in a two-stroke/cycle, crosshead diesel engine serves to __________.
eliminate the necessity for an oil scraper ring
prevent side thrust and cylinder scoring
prevent sludge and dirty oil from entering the crankcase
scrape oil and carbon deposits off the cylinder walls
The proper location for journal bearing oil grooves is __________.
in the region of the load bearing surface
as a side relief where the two shells meet
at the bottom of the bearing
halfway between bottom and where shells meet
How are hydraulic valve lash adjusters on diesel engine rocker arm assemblies lubricated?
Cup-fed grease
Sealed self-lubricators
Metered hydraulic oil supply
Forced lube oil supply
Main propulsion diesel engines having a bore exceeding 300 mm are to have at least __________.
two independent means of starting the engine
five air starting valves to permit the admission of starting air at any crank angle
one (explosion relief) valve at the position of each main crank throw
two engine driven lube oil pumps capable of parallel operation
Bearing wear on a split sleeve type bearing is normally measured with a __________.
ball anvil micrometer
pair of outside calipers and a dial indicator
pair of inside calipers
depth micrometer
If the load on a diesel engine equipped with an isochronous hydraulic governor is increased, after compensation is performed by the governor, the engine speed will __________.
remain the same
increase
decrease
fluctuate
In a single-acting diesel engine, the cylinder liner area that is most difficult to lubricate is the __________.
major thrust side
minor thrust side
top circumference
bottom circumference
Many diesel engines have pistons with concave heads to __________.
decrease air turbulence and improve fuel mixing
increase air turbulence and improve fuel mixing
prevent fuel afterburning when injection ends
prolong fuel afterburning when injection ends
If you observe smoke coming from the turbocharger of an auxiliary diesel engine, you should __________.
check the air filter for obstruction
check for an exhaust leak
check the exhaust temperature
secure the engine
A two-stroke/cycle diesel engine operates erratically, overspeeds, and fails to restart when cranked at normal speed. Which of the following problems is the most likely cause for the engine failing to restart?
Improper governor operation due to excess oil pressure
Damage to the governor due to excessive speed
Failure to reset the overspeed trip
Failure to reposition the fuel rack
A disadvantage of a two-stroke/cycle diesel engine is __________.
more power strokes per revolution
the use of scavenge air
more complicated valve gear
higher working temperatures of the piston and cylinder
Which of the following statements is true concerning the cetane number rating of diesel fuel?
The cetane number is obtained by comparing the fuel with cetane, a colorless liquid hydrocarbon.
The higher the cetane number, the shorter the ignition lag.
The highest cetane number of fuel is 100.
All of the above.
Which of the following statements is true concerning the cetane number of diesel fuel?
The cetane number affects the amount of injection lag.
The cetane number is an indication of the fuel's viscosity.
Ignition lag is reduced with fuels having a high cetane number.
The cetane number is of little significance in the combustion process.
The reversing mechanism on a large four stroke main propulsion diesel engine, can be operated by __________.
using double roller followers engaging individual cams lobes
displacing the camshaft axially according to a double cam lobe design
using a separate camshaft having a symmetrical cam lobe design and rotating the camshaft by an appropriate angle
all of the above
During the diesel engine power stroke, the side thrust developed on the piston is a result of the angle __________.
formed by the connecting rod and cylinder center line
of the bevel on the piston oil control rings
formed by the crank arm and crank pin
formed by the crank pin and flywheel
Which of the designs listed will keep the lobes from making contact in a Roots-type blower?
Drive chain
Blower timing gears
Air trapped between blower lobes
Oil filter between blower lobes
Diesel engine injection lag is caused by __________.
compressibility of the fuel
high fuel oil temperature
low injector popping pressure
excessive air turbulence
A diesel engine should use which type of lubricating oil?
Low viscosity
Cutting oil
High grade vegetable oil
Detergent oil
Where would a metal-edge disk type strainer normally be found on a diesel engine lubrication system?
pump discharge line
gravity tank inlet line
oil sump return line
pump suction line
