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单选题
The （） in the injector will lift at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.
A
needle valve
B
nozzles
C
piston
D
spring
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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
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单选题The injector pump is operated by a cam which drives （） up and down.A
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单选题The injector pump is operated by a cam which drives the plunger （）.A
top and bottomB
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单选题As the plunger moves up, the ports are closed and the fuel （） and delivered to the injector nozzle at very high pressure.A
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glass thermometerC
burdon tubeD
piezoelectric pressure transducer
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考题
单选题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 liftB
will be liftedC
will closeD
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low exhaust back pressureB
early fuel injection in one of the cylindersC
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单选题The amount of fuel injection into a diesel engine cylinder by a unit injector, is controlled by（）A
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late fuel injectionB
early fuel injectionC
high exhaust temperature from that cylinderD
decreased effective stroke from that injector
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单选题The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.A
assist in a quick cutoff of fuel injectionB
allow oil backflow from the injector to the helixC
reduce fuel oil pressure between injection strokesD
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单选题麻醉机APL阀的意义（）。A
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APL是auto pressure lift的简写
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reduce fuel booster pump pressureC
adjust the fuel rackD
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单选题An increase in the fuel injection pump discharge pressure can be caused by a/an （）A
leaking delivery valveB
excessive bearing end playC
plugged injector spray holeD
increased plunger stroke
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单选题In a refrigeration system, which of the following statements describes the actions occurring when a solenoid valves, used in conjunction with an unloader head is energized?（）A
The solenoid valves directs high pressure gas to the valve lifting device raising the suction valve off its seat and causing one specific cylinder to become unloadedB
The solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be openedC
When the solenoid valve becomes energized, the valve ports become closed, allowing discharge pressure to build up above the piston, shifting it and causing it to unloadD
The solenoid valve allows the refrigerant to pass from the suction chamber to the top of the unloader piston, causing the piston to lift and unload the cylinder
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