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单选题
The mechanical efficiency of an engine is always less than 100% （） losses occurring in the form friction.
A
because
B
since
C
due to
D
owing to
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The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually______.A.greater than the average exhaust manifold pressureB.less than the average exhaust manifold pressureC.greater at the turbine wheel than at the impellerD.greater at reduced engine speed
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Some companies have introduced flexible working time with less emphasis on pressure ____A.than more on efficiency
B.and more on efficiency
C.and more efficiency
D.than efficiency
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单选题When the opening pressure of a diesel fuel injector is greater than that specified by the engine manufacturer，the （）A
quantity of fuel injected is decreasedB
quantity of fuel injected will always be increasedC
start of injection is advancedD
duration of injection will always be greater
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单选题The mechanical efficiency of an engine （） because losses occur in the form of friction.A
is always less than 100%B
is always more than 100%C
is always equal to 90%D
is always less than 90%
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单选题If the engine can be started and maneuvered on high viscosity fuel, the （）of the fuel reaching the injectors should be raised to such a point that the viscosity is less than the required value, ie27c St.A
pressureB
temperatureC
viscosityD
density
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单选题Which method listed below is acceptable by classification society to perform hose testing to weather tight hatch covers and closing appliances（）A
This is to be carried out at a maximum distance of 1,5m with a hose pressure not less than 2,0 kgf/cm2. The nozzle diameter is not to be less than 12mm.B
This is to be carried out at a maximum distance of 1,5m with a hose pressure not less than 3,5 kgf/cm2. The nozzle diameter is not to be less than 5mm.C
This is to be carried out at a maximum distance of 1,5m with a hose pressure not less than 4,0 kgf/cm2. The nozzle diameter is not to be less than 8mm.D
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单选题Nearly half the world’s population ______.A
still lives in the developing countriesB
earns less than $1 a dayC
has no access to safe drinking waterD
1ives on less than $2 a day
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单选题The conclusion that mechanical efficiency is always （） 100 percent is correct.A
small thanB
more thanC
little thanD
less than
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单选题The diesel engine consumes considerably less fuel than the steam engine for equal output, （） enables a motor-ship to load more cargo.A
whyB
whichC
in whichD
on which
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单选题When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?（）A
Quantity of fuel injected tends to be decreasedB
Quantity of fuel injected will always be increasedC
Start of injection tends to be advancedD
Duration of injection will always greater
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单选题Which of the following statements is true concerning the overall efficiency of air compressors?（）A
High pressure compressors are more efficient than low pressure compressorsB
Mechanical efficiency divided by compressor efficiency will equal the overall efficiency of the compressor unitC
Two stage compressors are generally more efficient than single stage compressorsD
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单选题If the compression ratio is increased on any diesel engine, （）A
the expansion ratio will decreaseB
combustion will be slowed downC
thermal efficiency will decreaseD
thermal efficiency will increase
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单选题Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.A
The direction of pressure on the journal in four-stroke engine is continuouslyB
positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engineC
four-stroke engines usually utilize a heavier grade of oil than tow-stroke enginesD
Low-stroke engines usually consume less lube oil than four-stroke engines
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单选题Whether a ship is sailing before the wind or sailing in the rough sea, we must reduce the fuel injection of the main engine.For the former one, it aims to prevent the main engine being（）, while for the later one, it aims to prevent the main engine being（）.A
overspeed；overloadB
overload；overspeedC
over torque；overspeedD
low mechanical efficiency；overload
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单选题You are anchoring in 16 fathoms of water．On a small to medium size vessel，the（）.A
Anchor may be dropped from the hawse pipeB
Anchor should be lowered to within 2 fathoms of the bottom before being droppedC
Scope should always be at least ten times the depth of the waterD
Scope should always be less than 5 times the depth of the water
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单选题In a diesel engine jacket water cooler, with seawater cooling the fresh water, the（）A
sea water temperature must never be warmer than 40℃B
jacket water pressure should always be greater than the sea water pressureC
jacket water temperature must always be less than 60℃D
jacket water pressure must always be less than the sea water pressure
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单选题Increasing the load on an engine equipped with a constant speed mechanical governor, will cause the engine speed to initially （）.A
increaseB
decreaseC
fluctuateD
remain constant
考题
单选题Which of the following statements is true concerning an oil cooler?（）A
The oil temperature is less than the cooling water temperatureB
The oil pressure is less than the cooling water pressureC
The oil pressure is greater than the cooling water pressureD
The oil flow control valve is always installed in the oil input line
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单选题A naturally aspirated diesel engine at full throttle will have an intake manifold pressure （）A
slightly less than atmospheric pressureB
approximately equal to exhaust manifold pressure at all timesC
that is widely fluctuating constantlyD
decreasing as engine load increases
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单选题A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine（）A
has little or no internal frictionB
has a lower effective compression ratioC
operates with scavenge air under a positive pressureD
operates without energy absorbing intake and exhaust strokes
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单选题Which of the factors listed has the greatest effect on the mechanical efficiency of a diesel engine?（）A
temperature of the intake airB
friction within the engineC
mechanical condition of the superchargerD
mechanical condition of the turbocharger
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单选题A SECONDARY function of a waste heat boiler is to （）.A
reduce engine exhaust noiseB
reduce engine back pressureC
increase engine cycle efficiencyD
increase turbocharger efficiency
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