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单选题
The interior of some diesel engine saltwater heat exchangers are protected from corrosion by the use of（）
A
aluminum plates
B
lead cathodes
C
copper baffle plates
D
sacrificial zincs
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From the last paragraph we can learn that __A. some pipes have to be re-arranged in winterB. the system can do more than warming up the buildingC. the exchangers will pick up heat from the street surfaceD. less heat may be collected in winter than in summer
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In an auxiliary diesel engine bypass type lubricating oil system, the main lube oil pump forces_______ .A.all of the oil used by the engine through a filterB.some of the oil used by the engine through a filterC.some of the oil used by the engine through a centrifugeD.all of the oil used by the engine through a centrifuge
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Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?A.Baffle plates that have been bent during prior removalB.Leaks m the cooler tube nestC.Operating the engine while maintaining a high sea water outlet temperatureD.A punctured sea water strainer supplying cooling water to the heat exchanger
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Immediately after any diesel engine is started, the engineer should check the ______.A.crankcase pressureB.lube oil pressureC.saltwater pressureD.exhaust temperature
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A bypass line provided around a waste heat auxiliary boiler in a diesel engine exhaust system, may be used to avoid boiler ______.A.corrosion at low engine loadsB.erosion at high engine loadsC.overload at high engine loadsD.scaling at all exhaust temperatures
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单选题As a heat engine,（） energy is the source of power by which the diesel engine can be operated.A
electricB
heatC
mechanicalD
exhaust
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单选题In a diesel engine, offers the heat energy directly（）； works as working medium and changes the heat energy to mechanical energy（）A
the burning of the fuel； medium shaftB
fuel spray； fresh airC
fuel； fuel sprayD
the burning of the fuel； the burned gas mixture
考题
单选题Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?（）A
Baffle plates that have been bent during prior removalB
Leaks in the cooler tube nestC
Operating the engine while maintaining a high sea water outlet temperatureD
A punctured sea water strainer supplying cooling water to the heat exchanger
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单选题The diesel engine exhaust gas bypass, as fitted with some waste heat boilers, is installed to （）A
prevent engine back pressure at heavy loadsB
increase total engine efficiency at low loadsC
prevent boiler corrosion at low engine loadsD
improve engine fuel consumption at any load
考题
单选题Which of the following conditions could contribute to the cracking of a diesel engine cylinder head?（）A
Leaking seal ringB
Insufficient heat transfer from the exhaust valvesC
Block cooling water passages to the headD
Excessive scavenging air provided to the engine
考题
单选题If the jacket water temperature in an auxiliary diesel engine cooling system is lower than normal, the probable cause is （）A
air binding of the engine cooling systemB
a cracked water cooled exhaust manifoldC
blockage in the heat exchangerD
faulty operation of the thermostat
考题
单选题Incomplete combustion in a running diesel engine can cause piston rings to become stuck as a result of （）A
residual carbon depositsB
lube oil viscosity breakdownC
uneven heat expansion of the ringsD
uneven heat expansion of the piston
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单选题Increasing the compression ratio of a diesel engine while maintaining the designed rate of fuel flow will result in （）A
increased horsepowerB
reduced efficiencyC
increased heat lossD
lower cylinder pressures
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单选题In conventional systems, the injection pressure（）, while it’s（）in common rail diesel engines.A
fluctuates with the engine speed to some extent, independent of the engine speedB
keeps constant at all engine speed, dependent on the engine speed to some extentC
keeps constant at all engine speed, independent of the engine speedD
is decided by the engine speed, constant at all engine speed
考题
单选题In a diesel engine cooling system, the high temperature alarm contact maker will be activated on excessively high water discharge temperature from the （）A
raw water pump dischargeB
expansion tank outletC
cooling water heat exchangerD
outlet engine jacket water outlet
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单选题Which of the following statements is correct concerning diesel engine cooling water systems?（）A
Each engine must have its own engine driven cooling water pump capable of providing cooling for all ranges of operationB
propulsion engines with bores exceeding 200 mm are to be fitted with a means to display the cooling water temperature of each cylinderC
At least two independent sea suctions are to be provided for supplying water to the engine jackets or to the heat exchangersD
Suitable strain are to be fitted between the circulating pumps and heat exchangers when sea water is used for direct cooling
考题
单选题In motor ship, （） is often used to recover some of the heat carried in the exhaust gases from the main engine.A
an diesel oil heaterB
a waste heat boilerC
a fresh water generatorD
all the above
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单选题Trunk-type diesel engine pistons are most effectively cooled by heat（）A
conducted through the engine blockB
conducted to water cooled cylinder wallsC
conducted through the piston crownD
loss to escaping exhaust gases
考题
单选题What preventative maintenance should be done frequently to diesel engine starting air receivers?（）A
Drain the accumulated moistureB
Test the relief valvesC
Watch the temperature to prevent fluctuations in pressureD
Clean the interior to remove oil and foreign matter
考题
单选题Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the （）A
electronic ignition systemB
compression of air by the pistonC
friction in the fuel injectorD
fuel oil bearing system
考题
单选题The essential part of the diesel engine, whose function is to convert the heat energy into the mechanical power, is the （）.A
crankshaftB
pistonC
connecting rodD
bearing
考题
单选题The purpose of compressing the air within the cylinder of a diesel engine is to （）A
produce the heat for ignitionB
decrease injection lagC
increase ignition delayD
aid in exhausting burnt gases
考题
单选题Which of the general advantages listed does the electrical pyrometer have over the mechanical pyrometer?（）A
When heated, it will move proportional to the amount the metal has lengthened or expandedB
The pointer associated with the pyrometer scale can be made to also measure engine RPMC
It can be utilized in exhaust manifolds and heat exchangers interchangeablyD
It can indicate temperature at a distant point from the source heat
考题
单选题The function of diesel engine piston compression rings is to （）.A
prevent piston side thrustB
prevent engine friction lossesC
transmit heat from the piston to the cylinder linerD
remove oil from the cylinder combustion space
考题
单选题Sacrificial zinc anodes are used on the saltwater side of diesel engine heat exchangers to（）.A
reduce electrolytic action on heat exchanger metalsB
keep heat transfer surfaces shiny and cleanC
prevent rapid accumulation of marine growthD
provide a protective coating on heat exchanger surfaces
考题
单选题A faulty thermostatic bypass valve, in a diesel engine cooling system, can result in （）A
excessive time required for warming-upB
excessive freshwater corrosionC
scale formation on the saltwater sideD
saltwater mixing with the freshwater
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