轮机英语试题二十三

试题二十三

一、单项选择题：

1.

Because the castings of smaller engines are not so big and heavy, ______ and cylinder block

may be made in one piece.

A.

the column

B.

the jacket

C.

cylinder cover

D.

cylinder liner

2.

______ of an engine crankshaft can be detected by measuring deflections of crank webs for

each unit of the engine.

A.

Misalignment

B.

Length

C.

Strength

D.

Stresses

3.

A common trouble with the fuel pump plungers or fuel valve spindle is______.

A.

broken down

B.

stuck

C.

oil leakage

D.

carbonized

4.

Diesel fuel oil having a low cetane rating can result in ______.

A.

improved cold weather starting

B.

smoother engine operation

C.

combustion knock

D.

reduce ignition lag

5.

______ is arranged for cleaning the lubricating oil in the system and clean oil can be

provided from a storage tank.

A.

A filter

B.

A centrifuge

C.

A distiller

D.

A generator

6.

The emulsion of the oil is mainly caused by ______.

A.

the solid impurities of large particle

B.

the solid impurities of fine particle

C.

the water content

D.

both water and solid

impurities

7.

Cylinders of marine diesel engines are normally cooled by ______.

A.

sea water

B.

fine mineral oil

C.

sanitary water

D.

fresh water

8.

______ are fitted in the exhaust system and facilitate charge removal and scavenging in each

cylinder.

A.

Diffusers

B.

Compressors

C.

Steam boilers

D.

Soot blowers

9.

______ device is provided to prevent starting air from being admitted to the cylinder before

the reversing is completed.

A.

An automatic

B.

A transmission

C.

A self-regulating

D.

An interlocking

10.

The difference between a supercharged engine and an un-supercharged engine is that ______

operates at an increased pressure.

A.

the later

B.

the latter

C.

the former

D.

the farmer

11.

______ for attachment to the propeller shaft also accommodates the turning gear and is

integrally forged with the crankshaft.

A.

The coupling flange

B.

The camshaft

C.

The cross-head pin

D.

The cylinder

jackets

12.

A(n) ______is a chemical or electro-chemical attack on the metal surface which may be

further increased if the sea-water is polluted.

A.

errosion

B.

corrosion

C.

cavity

D.

scouring

13.

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

B.

closing

C.

opened

D.

closed

14.

The governor of a generator engine is to ______.

A.

make the engine stop

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

B.

regulate the timing of camshafts

C.

make the rpm stabilize at any required value

D.

make the engine run at nearly constant speed

The ability of the governor to prevent fluctuations(

波动

) in engine speed is termed ______.

A.

sensitivity

B.

stability

C.

promptness

D.

speed droop

A governor automatically controls engine speed by regulating ______.

A.

fuel supply

B.

firing order

C.

engine load

D.

oil level

The volute pump is one in which the impeller ___.

A.

discharges into a gradually widening channel

B.

has stationary diffuser vanes

C.

produces no kinetic energy

D.

All of the above

are true

As for a hydraulic single action vane pump, the inner wall of the stator is usually of ______

shape.

A.

circular

B.

elliptical(

椭圆的

)

C.

rectangular

（矩形的）

D.

hexagon

Gear pumps are of positive displacement type pumps because they discharge a near constant

amount of liquid ______ pressure.

A.

depending on

B.

in relative to

C.

regardless of

D.

because of

If an operating auxiliary boiler has a water pH reading of 7, you should ______.

A.

bottom blow the boiler

B.

treat the water with caustic soda

C.

treat the water with chemical scavengers

D.

reduce the water alkalinity to recommended readings

When steam is being raised on a boiler, the water level will normally ______.

A.

drop as the boiler warms up

B.

rise as the boiler warms up

C.

remain unchanged until the boiler is hot enough

D.

rise and fall with the steam demand

For a purifier, changing to a gravity disc with larger hole diameter will move the interface

towards the ______.

A.

bowl periphery

B.

bowl center

C.

upper surface

D.

lower surface

When in operation, it is unavoidable that a small amount of oil ______ through leakage, and

in order to compensate for these leaks the system is connected to a feed pump.

A.

escapes

B.

overheats

C.

expands

D.

accelerates

The pollution prevention regulations state that slop oil and sludge that result as part of normal

fueling operations should be disposed of by ______.

A.

discharging ashore into the sewer system

B.

sealing in disposable plastic barrels aboard ship

C.

discharging into a shore tank or slop barge

D.

dumping into the ship

’

s bunker tanks

If a bilge pump failed to build up discharge pressure, you should check for ______.

A.

excessive water in the bilges

B.

a clogged suction strainer

C.

oil in the bilges

D.

all of the above

26.

Here some oil in the oily water separator, as a result of its lower ______, will separate and

rise into the oil collection space.

A.

temperature

B.

viscosity

C.

density

D.

velocity

27.

The drive motor will have a brake arranged to fail-safe, i.e. it will ______ the load if power

fails or machine is stopped.

A.

cast

B.

put

C.

hold

D.

let out

28.

Morring winches are often combined with ______ units so that one prime mover drives both.

A.

crane

B.

hatch cover

C.

windlass

D.

steering gear

29.

The air compressor pumps air to the ______.

A.

air cylinder

B.

combustion chamber

C.

steam drum

D.

expansion

tank

30.

The process of boiling seawater in order to separate it into freshwater vapor and brine is

usually defined as ______.

A.

dehydration

B.

condensation

C.

evaporation

D.

dissolution

31.

The cooler as the liquid becomes, ______.

A.

the faster it will evaporate

B.

the slower it will condense

C.

the slower it will evaporate

D.

the faster it will flow

32.

During working, thermostatic expansion valve should be ______.

A.

either all the way open or all the way closed

B.

normally fully open

C.

throttled depending on load

D.

controlled by liquefied pressure

33.

Prior to any overhaul work on electric equipment, it is important to ensure the circuits are

______.

A.

live

B.

dead

C.

excited

D.

on line

34.

Why is it desirable to operate paralleled AC generators at the same power factor?

A.

Circulating currents are kept to a minimum.

B.

Field excitation losses are kept to a minimum.

C.

Generator rotors will have a lesser tendency to hunt.

D.

Because a power factor increase will decrease kilowatt output.

35.

In a modern three-phase A.C. synchronous brushes generator, the excitation winding is on the

rotor. That means ______.

A.

the generator need not excitation.

B.

the winding on the rotor is for inputting excitation current.

C.

there are three phase windings on the rotor.

D.

the generator has brushes.

36.

The main generators are connected to ______.

A.

distribution boards

B.

section boards

C.

emergency switch boards

D.

main switch boards

37.

Usually the panels are interlocked with ______ so that the devices can be made dead before

the doors are opened.

A.

protective earth

B.

isolators

C.

ground switch

D.

circuit-breakers

38.

Which of the listed devices is used to measure pressure and convert it to an electrical signal?

A.

Transducer

B.

Reducer

C.

Transformer

D.

Rectifier

39.

A manometer is used to measure ______.

A.

pressure

B.

temperature

C.

volume

D.

specific

gravity

40.

An ohmmeter can be used to measure ______.

A.

current flow in a circuit

B.

voltage between two points in a circuit

C.

circuit continuity

D.

power

41.

Engine protection by means of an alarm or shutdown control can be obtained with devices

that are sensitive to ______.

A.

temperature

B.

pressure

C.

engine speed

D.

all of the

above

42.

When the current in a power transmission line is increased, the power loss ______.

A.

increases as the square of the current

B.

decreases as the square root of the current

C.

remains the same, as it is independent of current flow

D.

increases in direct proportion as the current

43.

The conclusion that mechanical efficiency is always ______ 100 per cent is correct.

A.

small than

B.

more than

C.

little than

D.

less than

44.

In a diesel engine, an extremely leaking exhaust valve can cause ______.

A.

misfiring

B.

pre-ignition

C.

interrupted scavenging

D.

reduced

scavenging

45.

A crack in a cylinder liner can be caused by ______.

A.

worn piston rings

B.

installation of undersized

sealing rings

C.

operating the engine at low loads

D.

restricted cooling water passages

46.

Poor combustion in a diesel engine can be caused by ______.

A.

high compression pressure

B.

low intake air temperature

C.

low exhaust pressure

D.

high scavenge air temperature

47.

Diesel engine exhaust temperatures may be used to indicate ______.

A.

leaking exhaust valves

B.

an overloaded cylinder

C.

a clogged injector nozzle

D.

all of the above.

48.

Combustion knock can occur in the cylinders of a diesel engine under any condition

permitting ______.

A.

a shortened ignition delay period

B.

a lean fuel/air mixture

C.

excess fuel in the combustion chamber

D.

rapid vaporization of injected fuel droplets

49.

During the inspection, the starting air valves should be closed ______ the engine from

turning.

A.

to increase

B.

to speed up

C.

to prevent

D.

to reduce

50.

Lower suction pressure of a pump may be caused by ______.

A.

too much air in the pipe line

B.

clogged strainer

C.

empty tank

D.

leaky

pipe

51.

To prevent excessive _____ in the transverse girders, the tie bolts are positioned as close to

the center of the crankshaft as possible.