题干选项A
1.The auxiliary engine and a.c.generator can
be connected with____.
A．cam
2.The term medium seed diesel engine is
curiently taken to mean an engine with an
operating rotational speed of ____ rpm.
A．below 300
3.The rotating range of the low speed diesel
engine is usually lower than____.
A．100rpm
4.Among the main propulsion units on board
the ship with the same capacity,the lightest
one is ___.
A．steam engine
5.Concerning diesel propelled vessels,the astern power is to provide for continuous operation astern____.A．equal to that vailable for ahead operation
6.A diesel engine is operating at1800rpm and
driving a propeller at600rpm.What is the
speed reduction ratio?
A．0.3 to 1
7.Engine displacement is equal to the cylinder____.A．area times the stroke
8In using reduction gears to obtain efficient propeller speeds, _____.A．they must be located at the after end of the engine
9.Maximum horsepower of a diesel engine is attained____.A．when the engine rpm is pulled down by overload
10 The term “moderate speed” was
previously interpreted as meaning a speed
which would enable a vessel ______ within
half the range of visibility.
A． stopping
11_____ can be found on most medium to large merchant vessels even if the main engine is either a steam turbine or 2-stroke crosshead engine.A． The medium speed 4-stroke trunk piston engine .
13 Medium speed engines have a _____ power to weight ratio than the slow speed two strokes, but due to the higher speeds tend to have _____ maintenance intervals.A．
higher/reduced .
14 The diesel engine is similar to the gasoline engine in that ______.A． both of them are ignited by compressed air
15 The reason why more and more of the large merchant vessels are being powered by medium-speed diesel engines is ______.A． they operate between 150 and 450 rpm
16 Gas turbines differ from steam turbines in that ______.A． steam rather than gas is used to turn a shaft
17 A diesel engine which is rated for normal operation at a crankshaft speed of 800 RPM, is commonly classed as a ______.A． slow-speed diesel
18______ is an opening for supplying seawater to condensers, pumps, etclocated in the hull below the waterline and having means for the attachment of associated piping.A． SEA CHEST .
19 A ship designed for carrying goods
requiring refrigeration is called ______.
A． REEFER .
20 The depth of the ship below waterline
measured vertically to the lowest part of the
hull is called ______.
A． trim
21 Which of the terms listed below represents the operational speed at which excessive engine vibration is created?A． Non-harmonic speed
23 Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to _____________.A． higher speed required
26 When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for work _____.A． remains the same
27which of the following statements is correct concernign available astern powr for diesel main propulsion systems?A．Astern power is to be provided in a sufficient amount to secure proper control of the ship in all normal circumstances
29 The abbreviation ‘M/E’ is used to represent the .A． measure equipment
30____ are increasingly used as main engine on merchant vessels, because they have a high Hp/Weight ratio.A． Slow speed diesel engines
31 Propulsion of the vast majority of
contemporary merchant ships (especially
containerships and VLCCs) utilizes____ as
prime mover.
A． gas turbine
32 Typical marine propulsion plants include____ directly coupled to the vessel’s single large-diameter, fixed-pitch propeller.A． a single, long-stroke, slow-speed, turbocharged, two-stroke diesel engine .
34Diesel engines insteads of steam engines were used as main engine on board ships is mainly because____.A．they have a high mechanical efficiency
39A propeller,in order to operate efficiently,
must rotate at a relatively _____ speed.
A． high
40.____arrangements have low temperature air and high temperature ehaust gas passing through adjacent ports,causing temperature differential problems for the liner material.A．Loop scavenge
41.____scavenge means both exhaust ports and scavenge ports are arranged to the same side.A．Uniflow
42____tappet clearance will cause the exhaust
valve to open early and close late in cycle and
will increase its maximum lift.
A．Excessive
43____tappet clearance will cause the exhaust
valve to open late and close early in cycle and
will reduce its maximum lift.
A．Correct
44_____ the cylinder will contain a great weight of air and will be capable of burning a great quantity of fuel.A． At the end of the compression stroke .
45_____ the supercharge pressure is, _____ power an engine develops.A． The higher/the more .
46_____ usually helps to induce air movement to assist combustion.A． Cylinder cover
47 A charge of fresh air is drawn into the
engine cylinder and then _____ by the moving
piston_____ very high pressure.
A． pressed/to
48 A diesel engine is similar to a gasoline
engine except that the former has no _____.
A． cross-head
49 A low speed engine requires___ reduction
gearbox____ it and propeller.
A．none, both
50 A reduction in load on a diesel engine
results in _____ of speed of the crankshaft.
A． a reduction
51 An increase in load on a diesel engine
results in _____ of speed of the crankshaft.
A． a reduction .
52 An indicator diagram is a pressue-volume
graph taken from the pressure in the ____ of a
working engine.
A．crankcase
53 As a heat engine, _____ energy is the source
of power by which the diesel engine can be
operated.
A． electric
54. At least___ cylinders in a two-stroke
engine will be configured to ensure that the
engine can be started with the crankshaft at
whatever position.
A．6
55.A t least___ cylinders in a four-stroke
engine will be configured to ensure that the
engine can be started with the crankshaft at
whatever position.
A．6
56 Charging-air pressure increases if there is incorrect combustion and drop in the _____ of the diesel engine.A． machine efficiency
57 Diesel engines are started by supplying _____ into the cylinders in the appropriate sequence for the required direction.A． cooling water
58 Diesel engines are started by supplying
_____ into the cylinders in the appropriate
sequence for the required direction.
A． fuel oil
59 Due to _____ action of pistons some relative motion between parts in contact in the coolant supply and return system must occur.A．reciprocating .
60 During the suction stroke, the piston is
moving _____.
A． inwards
61 During working, when the piston is near the
_____, the air ignites the fine spray of fuel.
A． TDC .
62 Engine _____ refers to the relative time of position of crank, at which each operation during the cycle is commenced and is completed.A． timing .
63 Engine _____ refers to the relative time of position of crank, at which each operation during the cycle is commenced and is completed.A． timing .
64 Exhaust temperature increases in all
cylinders, the possible cause may be_____(1)
increased scavenging air temperature, (2) air
in fuel pumps and fuel valves, (3) fouling of air
and gas passages.
A． (1)+(2)
65 For a diesel engine, when the piston is at
the _____, the clearance volume is the largest.
A． TDC
66 For an ordinary four-stroke diesel engine
the exhaust valves close _____.
A． after TDC .
67 For an ordinary four-stroke engine the
exhaust valves open _____.
A． after TDC
68 For an ordinary four-stroke engine the inlet
valves open _____.
A． after TDC
69 For an ordinary modem marine four-stroke
engine the inlet valves close _____.
A． after TDC
70 Four strokes consist of suction, compression, _____ and exhaust stroke.A． combustion .
72 Fuel injected into a diesel engines cylinder is ignited by _____.A． the heat compressed fuel/air mixture in the cylinder .
73 Heat energy is a source of power, but _____ will cause damage to the engine.A． excessive heat .
74 If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in _____.A． the crankcase explosion .
75. If the flame from comustion in the cylinder of a two-stroke engine passes the piston into the space between the piston and the stuffing box, the accumulation of flammable mixture would be ignited, thus resulting in____.A. the crankcase explosion
76 In a _____ engine the charge of air in the cylinder before compression commences is above atmospheric pressure.A． pressure charged .
77 In a four-stroke engines the camshaft rotates at _____.A． half the engine rotational speed .
78 In a two-stroke engine the camshaft rotates
at____ the engine rotational speed.
A．half .
79 In a four-stroke engine the camshaft rotates at _____.A． half the engine speed .
80 In an ordinary diesel engine the fuel
injection begins _____.
A． after TDC
81 In an ordinary four-stroke engine the
exhaust valves open _____
A． after TDC
82 In four strokes engine, the cycle of events is
completed in four strokes of _____.
A． the cylinder
83 In the four-stroke engine, it takes _____ to make one power stroke.A． one propulsion
84 In the suction stroke air is induced into the cylinder _____In the compression stroke the air is compressed.A． by an fuel valve
85 In the two-stroke engine, each revolution of ____ makes one power or working stroke.A．the turning gear .
86. In the two-stroke engine, inefficient
scavenging and other losses reduce ____ to
about 1.8.
A．the output .
87 In today’s practice, with cylinders of
equal diameter of bore and equal revolutions,
the two-cycle engine delivers a power about 80
percent ____ than that of the four-stroke one.
A． greater .
88 On a four-stroke diesel engine, when the
piston is driven downwards by the expanding
gas, it delivers power to the crankshaft
through the _____.
A． thrust block
89 Since the burning or combustion takes place within the engine itself, the engine is known as _____.A． a fire -tube boiler
90 The _____ engine is used for alternators and some times for main propulsion with a gearbox to provide a propeller of between 90 to 120 rpm..A． four-stroke .
91 The abbreviation “MIP” stands for___.A．middle
indicating
pressure .
92 The abbreviation BDC means _____.A． Boston
Diesel Company 93 The abbreviation TDC means _____.A． top dead
center .
94 The compressed air is admitted to each
cylinder through a cam operated by starting
air valve when the piston has just passed its
_____.
A． BDC
95 The conclusion that mechanical efficiency is
always _____ 100 per cent is correct.
A． small than
96 The cylinder contains a great weight of air and is capable of burning a great quantity of fuel at_____.A． the beginning of the compression stroke .
97 The diesel engine is a type of _____.A． turbine
engine
98 The diesel engine is a type of internal combustion engine which ignites the fuel by injecting it into hot, high pressure air in a _____.A． air bottle
99 The distance from TDC to BDC of the
diesel engine is called _____.
A． gap
100 The energy for pushing this piston up can be supplied from _____, so that the piston can keep moving up and down.A． the same piston
101 The figure that the volume of air at BDC is divided by the volume of air at TDC is termed as____.A．ignition ratio .
102 The four strokes are called suction,
compression, expansion and exhaust, but only
_____ stroke provides the power to drive the
ship.
A． suction
103 The four-stroke engine is used for _____
and sometimes for main propulsion with a
gearbox to provide a propeller speed of
between 90 to 120 rev/min.
A． alternator .
104 The fresh air coming in through the inner air ports, is compressed by _____ to a higher pressure.A． the cylinder head
105 The indicated power of an engine can be
obtained by taking the _____.
A． precautions
106 The main factor determining the output of
each cylinder is the cylinder _____.
A． density
107 The main factor which determines the output of each cylinder is _____.A． the cylinder weight
108 The majority of medium speed and high
speed marine diesel engines for main or
auxiliary drive operate on the _____ cycle.
A． two-stroke
109 The marine diesel engine is a type of diesel
engine used on shipsThe _____ of its operation
is not very difficult to understand.
A． principle .
110 The mechanical efficiency of an engine _____ because losses occur in the form of friction.A． is always less than 100% .
111 The period of valve overlap is when _____.A． the inlet
valve is open
112. The piston forces are transmitte over the entire length of the cross-head pin then to ___ via the lower half single bearing shell.A．the piston rod .
113 The piston moves up and down, thus
causing the rotational movement of the _____.
A． crankshaft .
114 The piston moving up and down keeps the
crankshaft _____.
A． to revolve
115 The ports are drilled in the liners at an angle of approx20℃ the result being that _____ is given a rotary movement.A． the scavenging air .
116 The scavenging air ports are located at
_____ that they are just exposed by the upper
edge of the piston when the piston is in the
bottom dead center position.
A． so a height
117 The slow speed main engine propulsion diesel operates on two-stroke cycle. At this low speed the engine requires no reduction gear box between it and ____.A．thrust blocks .
118 The slow speed main propulsion diesel usully operates on ____.A．the four stroke cycle .
119 The term _____ refers to one complete sequence of operations required to produce power in an engine.A． diesel engine
120. The two-stroke cycles begins with the piston____, with the air inlet ports or scavenge ports in the side of the cylinder being opened.A．coming down from the BDC .
121. The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with ___ in the sides of the cylinder being opened.A．scavenge ports .
122 The two-stroke cycle begins with the
piston coming up from the bottom of its stroke,
with scavenge ports in the sides of the cylinder
being _____.
A． shut
123 The working cycle of a four-stroke diesel engine consists of four events: (1) compression;
(2) expansion; (3) exhaust; (4) suctionThe correct sequence is _____.A． (4)-(2)-(3)-(1)
124. We call a ship equipped with a diesel
engine as main engine____.
A．a tug boat .
125. Two-stroke enginew invariably have___to
admit air when uncovered by the descending
piston.
A．inlet ports .
126. When ___ is compressed, its temperature
rises so that it ignites the fine spray of fuel
injected into the cylinder.
A．the oil .
127. When the exhaust ports or valves are opened, the ___ begins to exhaust.A．carbon and water .
128 When the piston reaches the top of its
stroke, the temperature of the air___ to very
high valve.
A．raises .
129. When the piston reaches the top of its
stroke, ___ the pressure___ the temperature of
the air rise to very high valve.
A．either, or .
130. When the piston reaches the top of its
stroke, both the___ and the temerature of the
air rise to very high valve.
A．density .
131When the rev/min decreases, the governor
weights move___, causing subsequent motions.
A．inwards .
132 When the rev/min increases the governor
weights move___, causig subsequent motions.
A．inwards .
133 When the starting air valve closes on one
cylinder, another starting air valve has _____
opened on another cylinder whose piston has
just commenced its downward stroke.
A． just
134 Which of the following can be directly
obtained by means of an indicator card?
A． power
135 Which of the following can be obtained by means of an indicator card?A． the peak pressure in a cylinder .
136 Which of the following firing order may
be used for an 6 cylinder engine?
A． 1-2-3-4-5-6
137 Which of the following is true about the fuel injection with an ordinary diesel engine?A． The process begins after TDC
138 While engine is in operation the piston
moves up and down, thus causing the rotation
of the _____.
A． crankcase
139 With four-stroke engines, it takes four
revolutions of the crank shaft to make _____
power stroke(s).
A． 1
140 With tow-stroke engines, it takes four revolutions to make _____ power stroke(s).
A． 1
141.Owing to its___ , the low speed cross-head diesel engine is widely used on board ship as a main engine.A．smaller size and simple construction .
142 If we turn the four-stroke diesel engine
into the two-stroke one with the same volume
of the cylinder and same rpm, the capacity is
to increase____.
A．60 percent .
143. The stroke coefficient of the two-stroke
diesel engine is ____.
A．1 .
144_____ the compression ratio, _____ the proportion of the heat energy of the combustion turned into useful work at the crankshaft, other things being equal.A． The high / the large
145 Cylinder wall temperature, fuel oil supplier, and oil passage _____.A． are interdependent .
146 Suppose the rated capacity of the main
engine of a ship is 10,000 kW at 100 rated
rpm, then when at 80 rpm its capacity should
be _____.
A． 800 kW
147_____, so they are widely used on board ship nowadays.A． Diesel engines have more advantages in comparison with gasoline engines .
148 A diesel engine burns _____ a gasoline engine of the same capacity in the same period of time.A． as much fuel as
149 When the fuel oil is burning in the combustion chamber, it _____.A． gives up large amount of heat
150____ into the cylinder because no fuel can burn _____ it.A． Air must be admitted/without .
151 Fuel oil begins injection into the cylinder of a four-stroke/cycle diesel engine during the _____.A． intake stroke
152 A naturally aspirated diesel engine at full throttle will have an intake manifold pressure _____.A． slightly less than atmospheric pressure .
153 In a two-stroke/cycle diesel engine, the process of scavenging begins as the___.A． piston nears and passes TDC
154 The camshaft drive is designed to maintain proper camshaft speed relative to crankshaft speedIn maintaining this relationship, the camshaft drive causes the camshaft to rotate at .A． one half crankshaft speed in a two-stroke cycle diesel engine .
155 The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by _____.A． direct action of cam shaft
156 The speed of the camshaft in a two-
stroke/cycle diesel engine, running at 950
RPM, is _____.
A． 475 RPM
157 Cylinder lubrication oil for low speed main propulsion diesel engines is admitted to each cylinder during _____.A． the power stroke
158 In a four-stroke/cycle diesel engine, the camshaft rotates at _____.A． twice the crankshaft speed
159 The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by
_____.A． large conical springs
160 In a tow-stroke/cycle diesel engine, the camshaft rotates at _____.A． twice the crankshaft speed
161 a four-stroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be_____.162A． 525 RPM
162 What is the speed of the crankshaft in a
four-stroke/cycle engine when the camshaft is
turning at 750 rpm?.
A． 375 RPM
163 A two-stroke diesel engine exhaust
temperature will be lower than a four-stroke
diesel engine of the same displacement because
the _____(1) scavenging air is cooling the
exhaust gases; (2) exhaust cycle time is longer.
A． (1) only .
164 With which of the following types of diesel engine arrangements is a waste heat boiler most likely to produce the maxium steam pressure, temperature, and flow conditions?A .Supercharged, four-stroke/cycle diesel engine
165 The camshaft on a four-stroke/cycle diesel engine provides a means to operate the _____.A． fuel injectors
166 A two-stroke diesel engine exhaust temperature will be lower than a four-stroke diesel engine of the same displacement because the _____(1) MEP is lower and the scavenging air is cooling the exhaust gases; (2) valve overlap in a four-stroke.A． (1) only is correct .
167 The linear motion of a diesel engine piston
is converted to the rotary motion required to
drive gears, propeller shafts, and generators
by the _____.
A． flywheel
168 The rotary motion of a diesel engine
crankshaft is obtained from the up and down
motion of the piston via the _____.
A． camshaft
169 The air supplied to a diesel engine is compressed to _____(1) provide heat for the ignition of the fuel; (2) decrease injection delay.A． (1) only is correct .
170 In diesel engines designed with a crosshead, the motion of the piston rod can be described as _____.A．reciprocating at the piston pin, rotary at the crank pin
171 What occurs in the combustion space of a diesel engine cylinder shortly after ignition and before the piston reaches TDC?A． Rapid increase in temperature with constant pressure
172 Successful combustion inside the cylinders of a diesel engine is dependent upon _____.A． fine atomization
173 In describing engine operation, what does the term “cycle” mean?A． The sequence of events that produce a power pulse .
174 Which statement about diesel engine combustion is true?A． Combustion does not begin until the piston starts down on the power stroke
175. Which of the listed design features is most common to a two-stroke/cycle low-speed main propulsion diesel engine?A．Crosshead construction .
176 All of the diesel engine cylinder firing pressures are normal, yet all of the exhaust temperatures are lowWhich of the following situations is responsible for this condition?A． Excessively early injection timing
177 A piston in a four-stroke/cycle diesel engine makes four strokes during each _____.A． crankshaft revolution
178 The diesel engine valve subjected to most severe conditions of service is the _____.A． cylinder exhaust valve .
179 Theoretical perfect combustion in a diesel engine yields by-products of _____.A． aldehydes and carbon dioxide
181 Turbulence in a diesel engine cylinder is of major importance in providing _____.A． proper fuel metering
185. The load is always placed on the lower half of the main bearings in a/an____.A．two-stroke/cycle engine .
187.When is fuel injected into a cylinder of diesel engines?A．Before air in the cylinder is compressed .
188. A change in the degree of fuel atomization in a diesel engine cylinder has the greatest effect on the____.A． cylinder air turbulence.
190.Why is it necessary to compress the air charge in the cylinders of a diesel engine?A．To ignite the fuel .
191. The average exhaust temperature of a two-stroke/cycle diesel engine with a turbine-driven supercharger is lower than a similar four-stroke/cycle engine at equal loads because____.A．two-stroke/cycle diesel engines have a higher MEP than four-stroke/cycle diesel engine .
195 Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?A． Exhaust and scavenging .
196.In a large slow-speed propulsion diesel engine, the fore applied to the piston is ___.A．against the crosshead during power stroke and away from the crosshead during the compression stroke .
198.which of the following statements is a description of the combustion cycle?A．The mechanics of engine operation .
199. The time between injection and ignition of the fuel is known as____.A．turbulence lag .
207 In diesel engines, the four basic events (intake, compression, power and exhaust) are performed once in _____.A． two crankshaft revolutions in a two-stroke/cycle engine
208 What causes diesel fuel to be ignited in the
cylinder of an operating diesel engine?
A． Spark plug
209 The highest pressure in a diesel engine
cylinder normally occurs _____.
A． at TDC
210 How many power strokes per crankshaft
revolution are there in an eight cylinder, two
stroke/cycle diesel engine?
A． One
211 The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being _____.A． open .
212 The purpose of the skirt or trunk in four-
stroke cycle engines is to act in a similar
manner to a _____.
A． crosshead .
213 The four-stroke cycle is so called because it takes _____ to complete the processes needed to convert the energy in the fuel into work.A． two strokes of the piston
214 In the suction stroke, the crankshaft is
rotating clockwise and the piston is moving
_____ the cylinderThe inlet valve is _____ and
a fresh charge of air is being drawn or pushed
into the cylinder by the turbocharger.
A． up/opened
215 It is during _____ that work energy is being put into the engine; during the other 3 strokes of the piston, the engine is having to do the work.A． the suction stroke
216 The four-stroke cycle begins with the piston .A． coming up from the BDC