The light and medium
fuels utilized in internal combustion engines provide a source of
________./food for microbiological organisms
What is to be installed
on an internal combustion engine if its cylinder bore exceeds eight
inches?/Explosion relief valves
Which statement regarding
the arrangement and location of explosion relief valves used on an internal
combustion engines is
true_____________?/Minimizing the danger from emission of flame is a key consideration
Which of the following
listed construction details of internal
combustion engines is required?/A warning notice to caution against the opening
of a hot crankcase for a specified period of time after shut down.
At what pressure should a
cylinder relief valve of an internal
combustion engine be set to relieve?/The device should be set to relieve at a
pressure not more than 40 percent in excess of the maximum firing pressure.
Successful combustion
inside the cylinders of a diesel engine
is dependent upon _____________./all of the above
Which of the combustion
parameters listed is used in a diesel
engine, but NOT related to the injection system?/Effective stroke
Precombustion chambers,
air cells, and energy cells in high- speed, small bore diesel engines all serve
to increase _____________./turbulence
Which statement about
diesel engine combustion is true?/Maximum cylinder firing pressure is not
developed until the piston passes TDC.
Proper atomization of
fuel in diesel engine combustion
chambers will _____________./improve combustion
The ability of a fuel
particle to travel into the combustion chamber before burning is called
_____________./penetration
Theoretical perfect
combustion in a diesel engine yields by-products of _____________./water vapor
and carbon dioxide
What is the term given to
the process of breaking up fuel oil into very fine particles for better
combustion?/Atomizing
Turbulence in a diesel
engine cylinder is of major importance
in providing _____________./complete fuel/air mixing
Poor combustion in a
diesel engine can be caused by
______________./low intake air temperature
Which of the following
conditions will tend to increase the ignition delay period of combustion in a
compression ignition engine?/Decreasing
the air charge temperature.
Combustion gas venting
through the expansion tank can be caused by a _____________./cracked cylinder
head
Combustion knock can
occur in the cylinders of a diesel
engine under any condition permitting _____________./excess fuel in the
combustion chamber
Turbulence of the
compressed air charge in a diesel engine cylinder increases _____________./the
efficiency of the engine
Combustion knock
occurring in a diesel engine can be caused by _____________./prolonged ignition
lag
Which of the following
statements is a description of the combustion cycle?/The heat process which
produces the force to initiate the movement of the engine parts.
An exhaust pipe from a
internal combustion engine may not need to be insulated when _________./it is
of the water jacketed type
Combustion knock
occurring in a diesel engine can be caused by ________________./low coolant
temperature
In a diesel engine, the
time taken to heat the fuel particles,
turn them into vapor, and bring about combustion is called
_____________./ignition delay
Diesel engines are
classified as reciprocating internal
combustion engines because they ______________./burn fuel in a chamber
where its energy moves a piston back and forth
The thermal energy
produced by an internal combustion engine is transformed into
______________./mechanical energy
Which of the listed
designs is effectively used to provide the turbulence necessary for proper
combustion in a diesel engine cylinder?/Precombustion chamber
Which of the following
statements represents the advantage of a precombustion chamber used in an
auxiliary diesel engine?/Timing of
injection does not need to be exact.
One advantage obtained
from the use of a precombustion chamber
in a diesel engine is _____________./smoother combustion
Precombustion chambers
differ from turbulence chambers in that precombustion chambers
_____________./contain a smaller portion of the total clearance volume
What is commonly used to
create turbulence in a diesel engine combustion system?/Shape of the piston
crowns.
Turbulence is created in
the cylinders of a diesel engine to _____________./help mix fuel and air
The main operating
characteristic of diesel engines which distinguishes them from other internal
combustion engines is the _____________./method of igniting fuel
What determines the
number of events occurring in a cycle of operation in an internal combustion
engine?/Type of engine (diesel or gasoline)
Which of the following
statements describes the operating characteristics of a precombustion
chamber?/When fuel oil is injected into the precombustion chamber, it does not
need to be as finely atomized as the fuel oil in diesel engines having direct
injection.
Modern marine diesel
engines using mechanical fuel injection, operate on a combustion cycle
which is _________./a combination of constant volume and constant pressure
Modern marine diesel
engines equipped with mechanical fuel injection operate on a combustion phase
within the cycle which is _________./a combination of constant volume and
constant pressure
A multi-orifice fuel
injection nozzle is usually used with which of the listed types of combustion
chamber?/Open combustion chamber
Black smoke exhausting
from an operating diesel engine is an indication of poor combustion which may
be caused by _____________./clogged air
intake passages
In a modern internal
combustion diesel engine, the load
carrying part of the engine is referred to as the _________./bedplate or
base
According to U. S. Coast
Guard Regulations (46 CFR), internal
combustion engine driven emergency generators shall be operated under load for
at least two hours at least once ____________./a month
According to Coast Guard
Regulations (46 CFR), how often shall internal combustion engine driven
emergency generators be operated under load?/Once a month for two hours
Which of the following
conditions is likely to develop if the thermocouple element of a pyrometer
becomes coated with excessive amounts of combustion by-products?/Pyrometer
responses will be retarded.
In a diesel engine, what
is the advantage of precombustionchambers over the open type of combustion
chamber? I. Precombustion chambers permit coarser fuel atomization. II. Precombustion chambers allow
lower fuel injection pressure./both I
and II
Modern marine diesel
engines equipped with mechanical fuel injection operate on a combustion cycle
which is _________./a combination of constant volume and constant pressure
Which internal combustion
engine starting system uses avane type fluid motor?/Compressed air
Which of the following
relationships should occur between the temperature developed in a combustion
space, and the compression ratio of the engine?/Higher compression ratios
create higher temperature.
Diesel engine blow-by is
the leakage of combustion gases past the _____________./compression and scraper
rings
In accordance with Coast
Guard Regulations (46 CFR) regarding
internal combustion engine exhaust manifold
installations, which of the following statements is true?/They may be
water-jacketed and cooled by the discharge from a pump which operates only when
the engine is running.
Open combustion chambers
are designed to _____________./provide proper fuel/air mixing
The primary purpose of
the open combustion chamber used in diesel engines is to _____________./provide
a place for combustion
Turbulence in the
combustion chamber of a diesel engine can be induced by
_____________./directional intake ports
The greatest turbulence
in a diesel engine cylinder is created
by the _____________./shape of the combustion chamber
Combustion knock will
most likely occur as a result of using a fuel with _____________./low ignition
quality
Coast Guard Regulations
(46 CFR) require a trial for ignition
period must not exceed ____________./15 seconds
The air supplied to a
diesel engine is compressed to___________.I. provide heat for the ignition of
the fuelII. decrease injection delay/I only is correct
For a given fuel, a
change in the compression ratio will affect the ignition lag by which of the listed
means?/An increase in compression ratio will decrease the ignition lag.
The longer the ignition
delay period occurs in a diesel engine,
the _____________./more rapid will be the rise in combustion pressure
Which of the following
conditions will tend to increase the ignition delay period of combustion in a
compression ignition engine?/Decreasing
the air charge temperature.
The rate of pressure rise
during the period following fuel ignition process in a diesel engine, is
influenced chiefly by the ____________./length of the ignition delay period
Which of the following
statements concerning the factors affecting ignition delay is correct?/An
increase in coolant temperature will decrease ignition delay.
The time between
injection and ignition of the fuel is known as _____________./ignition delay
The minimum speed an
engine must attain before ignition can occur depends upon __________./all of
the above
In a diesel engine, the
time period between fuel injection and ignition is usually defined as
_____________./ignition delay
The theoretical minimum
compression ratio necessary to ensure
compression ignition in a direct injection diesel engine is
_____________./0.50069444
In an operating diesel
engine, preignition can be caused by _____________./oil in the air charge
The rate of pressure rise
during the period following fuel ignition in a diesel engine is influenced by
the length of the ignition delay period due to the ______./turbulence of the
air change
The ignition quality of
diesel fuel becomes less critical as ______________./engine speeds decrease
One cause of diesel
engine fuel ignition delay is _______./ignition quality of the fuel oil
If fuel injection in a
diesel engine begins earlier than the design start of injection, ignition may
be delayed because the _____________./cylinder compression pressure may not be
high enough
In diesel engineering
practice, the term used to express the ignition quality of a particular fuel is
_____________./cetane number
The ignition quality of
diesel fuel is indicated by its
______________./cetane number
The ignition quality of
diesel fuel oil is indicated by the ______________./cetane number
The ignition quality of a
diesel fuel is indicated by the _____________./cetane number
The ignition quality of a
fuel oil is an important operational
consideration because it _____________./affects the starting ability of a cold
engine
The longer the ignition
delay period resulting from improper use of low cetane fuel, the
____________./more rapid the rise in combustion pressure
A mixture of 45% cetane
and 55% alpha-methyl-naphthalene is found to have the same ignition delay as a
sample of diesel oil. The sample can be described as having a/an
__________./cetane number of 45
When comparing different
fuels for different engines, the ignition quality of diesel fuel oils becomes a
less critical consideration as ______________./engine speeds decrease
Most practical diesel
engines today operate on a cycle which is a combination of the Diesel and Otto
cycles. In this process, compression ignition _____________./begins on a
constant volume basis
A diesel engine is turned
at normal cranking speed and no ignition occurs. This could be the result of
_____________./air bubbles in the fuel oil system
The amount of oil
consumed by a return flow-type fuel
atomization system, fitted with both supply and return meters, can be determined by the
____________./difference between the supply and return meter readings
A sprayer plate used in a
return flow fuel oil atomizer is correctly installed if the oil
__________./passes through the tangential slots before passing through the
whirling chamber
The amount of fuel oil
atomized by a return flow oil burner is directly controlled by the
____________./fuel oil back pressure
In comparison to straight
flow mechanical atomizers, return flow atomizers provide relatively uniform
atomization over a wide firing range due to the ____________./oil supply
pressure not having to be reduced at low loads to the point where poor
atomization occurs
Fuel droplets injected
into a diesel engine cylinder must have adequate penetration to
_____________./thoroughly utilize the air charge
Fuel injection systems
meter fuel, atomize fuel, and
_____________./inject fuel at the proper time
A variable capacity,
pressure atomizing, fuel oil burner functions to ____________./provide a wide
range of combustion
The firing range of a
variable capacity, return flow-type fuel atomizer is regulated to meet steam
demand by varying the ____________./fuel oil return pressure
Fuel oil penetration into
the cylinder of a diesel engine is _____________./reduced by finer atomization
Proper atomization of
fuel in diesel engine combustion
chambers will _____________./improve combustion
A change in the degree of
fuel atomization in a diesel engine
would most greatly affect _____________./fuel penetration
Fuel oil discharged to
the diesel engine cylinder is atomized
at the _____________./injector nozzle tip
A change in the degree of
fuel atomization in a diesel engine
cylinder has the greatest effect on the ____________./combustion in that
cylinder
In a diesel engine, what
is the advantage of precombustion chambers over the open type of combustion
chamber? I. Precombustion chambers permit coarser fuel atomization. II. Precombustion chambers allow
lower fuel injection pressure./both I
and II
A change in the degree of
fuel atomization in a diesel engine
greatly affects the _______________./fuel penetration
Which of the following
statements concerning fuel atomization
in a diesel engine cylinder is correct?/The greater the atomization, the lesser
the penetration. | |||
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