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单选题
Differential needle valves used in fuel injectors are directly closed by（）
A
cam action
B
spring force
C
fuel oil pressure
D
firing pressure
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单选题Maintaining the close tolerances in diesel fuel pumps and injectors requires the use of（）.A
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day tanksC
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单选题Which of the valves listed should be used either in the fully opened or the fully closed position?（）A
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单选题If the needle valve in a fuel injection nozzle sticks open （）.A
no fuel will be delivered through the nozzleB
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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
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单选题During the fuel injection period, fuel pressure must exceed cylinder gas pressure to （）.A
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单选题Starting air valves are held firmly on their seats by（）A
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单选题Differential needle valves used in fuel injectors are directly closed by（）A
cam actionB
spring forceC
fuel oil pressureD
firing pressure
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单选题Fuel injectors used in heavy fuel oil systems are usually provided with cooling to reduce（）.A
cold corrosion of the nozzlesB
fuel viscosity for better atomizationC
carbon accumulation on the nozzlesD
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单选题Proper filtering and straining of fuel oil is important because the （）.A
fuel oil pump will over-speed if dirt is not removedB
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fuel injectors may be damaged by foreign particles in the fuel oilD
dirty fuel will clog the intake air filter
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单选题The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）A
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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In some type of two-stroke engines, besides some small holes for（）, starting valve, safety valve, indicator cock, and central opening in each cylinder cover for mounting the（）A
fuel valves；exhaust valveB
exhaust valves；inlet valveC
fuel valves；inlet valveD
exhaust valves；fuel valve
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