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单选题
An electric heater built into some smaller diesel engines is used to （）.
A
raise lube oil viscosity for easier starting in cold weather
B
increase air inlet temperature
C
increase compression ratio
D
increase jacket water temperature for easier starting in cold weather
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单选题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 requiredB
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单选题Diesel engines are considered safer than gasoline engines because（）.A
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单选题（）, so they are widely used on board ship nowadays.A
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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
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is decided by the engine speed, constant at all engine speed
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单选题The cetane number rates fuels for diesel engines according to its （）A
antiknock characteristicsB
ignition qualitiesC
rates of vaporizationD
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单选题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 rpmB
they are connected to the propeller by gearingC
their smaller size and weightD
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单选题Some diesel engines are supercharged with a （）A
slam chargerB
turbochargerC
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单选题Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）A
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单选题Cast iron pistons used in large propulsion diesel engines are constructed with （）A
not taper what so everB
the skirt being tapered and smaller than the crownC
the skirt being tapered and larger than the crownD
the crown being tapered and smaller than the skirt
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单选题The most common forms of main drive used on deck auxiliaries are （）.A
steam plants, electric motors and compressed airB
diesel engine, hydraulic machinery and compressed airC
steam plants, electric motors and hydraulic machineryD
diesel engines, steam plants and hydraulic machinery
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单选题Valve cages are used on some large diesel engines to （）A
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reduce heat transfer from the valve seatD
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单选题Which of the following precautions must be taken if an electric immersion heater is used to keep the coolant in a diesel engine warm during the time the engine is secured?（）A
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The thermostatic bypass valves must be manually opened before the engine is startedC
The pressure cap must be removed while the engine is securedD
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考题
单选题All diesel engines are classified as（）.A
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单选题A waste heat boiler is installed on some diesel propelled vessels to （）.A
provide steam for emergency propulsionB
provide steam for the turbo-generatorC
heat the waste water tanksD
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考题
单选题The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）A
governor flyweight action on a pilot valve which controls fuel injectionB
governor flyweight motion acting on fuel controls through suitable linkageC
positioning a butterfly valve in the fuel delivery system positioningD
a servomotor piston attached to the fuel controls
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单选题The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the （）A
method of supplying airB
cooling systemC
method of igniting fuelD
valve operating mechanism
考题
单选题Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinderIf the cooling water temperature from all cylinders begins to rise above normal, you should suspect （）A
increase blow-by in all cylindersB
incomplete combustion in all cylinderC
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考题
单选题In some modern large diesel engines, which of the following is used as the support for the main bearings?（）A
BedplateB
BlockC
BaseD
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单选题When running a large, low-speed, main propulsion diesel engine on heavy fuel, which of the following precautions should be observed when switching back over to diesel oil?（）A
The diesel oil must never be allowed to mix with the heavy fuelB
The temperature of the fuel from the pre–heater should be gradually reduced after switching over the three–way valveC
The heating steam to the pre-heater should be secured as soon as the diesel fuel passes through the three-way valveD
The heating steam must be secured before the diesel oil passes through the three-way valve
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