The needle valve will open when the fuel pressure acting on the needle valve （） exerts a sufficient force to overcome the spring compression.

相似题目

• If the compensating needle valve of a hydraulic governor is opened more than necessary the governor will （）

  A . have a larger than normal dead band B . produce excessive speed response to a load change C . respond slowly to any change in engine load D . stabilize engine speed at the new governor setting

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• When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.

  A . just B . nearly C . merely D . already

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• For an ordinary four-stroke engine the exhaust valves open （）.

  A . after TDC B . before TDC C . after BDC D . before BDC

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• In a four-stroke cycle diesel engine the intake valves open （）

  A . before TDC and close after BDC B . after TDC and close after BDC C . before TDC and close before BDC D . after TDC and close before BDC

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• In an engine with air inlet valve and exhaust valve on its cylinder heads the fresh air will enter into the cylinder （） and the gases exhaust （）, there being an adequate overlap between the inlet opening and the exhaust closing.

  A . downwards；upwards B . upwards；downwards C . downwards；downwards D . upwards；upward

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• The bypass valve on a self-contained breathing device should be opened if（）.

  A . you are entering a space containing poisonous vapors B . you are entering a space containing explosive gases C . the regulator of the breathing apparatus malfunctions D . the face piece of the breathing device is too tight

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• A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . open B . close C . remain in its position D . flood the evaporator with refrigerant

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• The needle valve in the injector （） at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.

  A . will lift B . will be lifted C . will close D . will be closed

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• The high-pressure fuel opens the fuel valve and is sprayed into the cylinder in tiny droplets known as （）.

  A . injection B . penetration C . atomization D . compressio

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• If the needle valve in a fuel injection nozzle sticks open （）.

  A . no fuel will be delivered through the nozzle B . the nozzle will overheat and crack C . time of injection will change D . fuel will leak into the drain line

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• Which of the valves listed should be used either in the fully opened or the fully closed position?（）

  A . A gate valve B . A globe valve C . Any check valve D . Any needle valve

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• The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.

  A . be jammed B . be opened C . be seated D . be broke

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• Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）

  A . closing later B . opening sooner C . staying open for a shorter period of time D . staying open for a longer period of time

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• Excessive valve lash in an auxiliary diesel engine will cause the valves to open（）

  A . later and close sooner B . sooner and close later C . sooner and close sooner D . later and close later

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• Which of the fuel injection systems listed uses a spring loaded differential spray needle valve and individual pump for each cylinder?（）

  A . Common-rail injection B . Air injection C . Jerk pump injection D . Distribution injectio

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• If the engine is naturally aspirated, or is a small high-speed type with a centrifugal turbocharger, the period of valve overlap（）,ie when both valves are（）, will be and the exhaust valve will close some 10°top dead canter（）.

  A . open；short；after B . closed；short；after C . open；long；before D . closed；long；before

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• （） in what position the engine stops there will always be at least one of the cylinders with its starting air valve open to admit compressed air to start the engine.

  A . Because B . Owing to C . For D . No matter

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• For an ordinary four-stroke engine the inlet valves open （）

  A . after TDC B . before TDC C . after BDC D . before BDC

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• In the piping systems of a vessel，what type of valve gives the least resistance to fluid flow when fully open?（）.

  A . Globe valve B . Butterfly valve C . Gate valve D . Packless valve

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• A cracked diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . return to a neutral position B . flood the evaporator C . open D . close

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• When the relief valve opens it discharges high pressure refrigerant vapor to the （）.

  A . liquid strainer B . refrigerant inlet of the condenser C . inlet side of the evaporator D . suction side of the compressor

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• Adjustments to the compensating needle valve in a hydraulic governor should be made with the engine at （）

  A . maximum power at a normal load B . maximum power and load under normal conditions C . half speed and normal temperature D . normal operating temperature without a load

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• In an ordinary four-stroke engine the exhaust valves open （）

  A . after TDC B . before TDC C . after BDC D . before BDC

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• In a turbocharged four-stroke/cycle diesel engine, the exhaust valve remains open until after top dead center and the intake valve opens before top dead center to_______.

  A.produce a scavenging effect in the combustion space B.equalize cylinder and exhaust manifold pressures C.alleviate the difference in valve size between the intake and exhaust D.flush out condensate that collects after each compression stroke

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