In diesel engines designed with a crosshead, the motion of the piston rod can be described as （）.

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• Directional intake ports in diesel engines are used to （）.

  A . reduce air charge turbulence B . induce air swirl C . deflect hot combustion gas away from the valves D . oppose the effects of piston induced squish

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• Diesel engine fuel oil contamination often results in （）

  A . governor malfunctions B . fuel injection system malfunctions C . high cylinder lube oil temperatures D . low intake temperature

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• A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated four-stroke/cycle diesel engine, in order to in crease the （）.

  A . temperature of the exhaust gases B . energy supplied to the turbocharger C . air pressure to the intake manifold D . purge of exhausted gases from the cylinder

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• Which of the following statements is correct for the design and installation of diesel engine cooling water systems?（）

  A . An alarm device with audible and visible signals is required for all cooling water systems B . Propulsion engines with bores over 200 mm are to be fitted with cooling water jackets C . Each totally enclosed cooling system shall be provided with a suitable head tank D . Drain cocks are to be provided at the lowest points of all cylinder water jacket

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• Which of the following reasons represents why the designed compression ratio of a gasoline engine is lower than that of a diesel engine?（）

  A . compression must be low for effective spark ignition B . compression must be low for required horsepower and torque generation C . compression must be low to prevent pre-ignition D . compression must be low to have effective pre-ignitio

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• In some diesel engine designs,（）the injection of cylinder oil is timed to impinge when the piston and only impinge on（）

  A . is coming upward；cylinder ring belt B . is going downward；piston ring belt C . is coming upward；piston ring belt D . is going downward；cylinder ring belt

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• Engine coolant accumulating in the diesel engine lubricating oil can result from a （）

  A . low oil pressure B . high coolant pressure C . leaking fuel injector D . cracked cylinder head or liner

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• A supercharged diesel engine when compared to a similar naturally aspirated diesel engine, will develop an increase in （）

  A . ignition lag B . engine horsepower C . lube oil system pressure D . specific fuel consumptio

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• What causes diesel fuel to be ignited in the cylinder of an operating diesel engine?（）

  A . Spark plug B . Heat of compression C . Carburetor D . Glow ping

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• Worn main bearings in a diesel engine can result in （）

  A . decreased compression pressure B . increased lube oil pressure C . lower lube oil temperature D . excessive leakage past the piston ring

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• Lubricating systems for diesel engines are usually designed to initially provide lube oil to the engine （）

  A . camshaft beatings B . main bearings C . piston crowns D . cylinder wall

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• Fuel is ignited in a diesel engine cylinder by （）

  A . a spark plug B . injectors C . the heat of compression D . increasing jacket water temperature

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• A diesel engine is supercharged in order to（）

  A . lower the no-load RPMs B . provide more air for combine with the fuel C . increase the no-load RPMs D . provide more fuel combine with the air

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• An individual injection pump is designed for variable beginning and constant ending of injectionFor diesel engines operating at constant speeds, the start of injection will（）

  A . advance as the load increases B . retard as the load increase C . remain unchanged regardless D . always occur at top dead center

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• The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and （）.

  A . reduce water temperature B . reduce water turbulence C . provide an air cushion D . allow for an increase in water volume as the engine warms u

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• In the two stroke diesel engine, it is designed so that the oil impingement is timed to proceed only on the piston ring belt during（）

  A . compression stroke B . suction stroke C . expansion stroke D . exhaust stroke

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• Operating a propulsion diesel engine at less than 30% of designed normal load for prolonged periods will result in （）.

  A . decreased fuel consumption per brake horsepower B . more complete cylinder scavenging C . extended valve life D . carbon formation on combustion chamber surface

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• Critical speed in diesel engines occurs when engine torque pulsations become （）

  A . opposed to the crankshaft rocking couple B . resonant with the crankshaft natural frequency C . critical fore and aft crankshaft vibrations D . horizontal whipping motions of the crankshaft

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• Increasing the compression ratio of a diesel engine while maintaining the designed rate of fuel flow will result in （）

  A . increased horsepower B . reduced efficiency C . increased heat loss D . lower cylinder pressure

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• Defective governor in a diesel engine may lead to （）.

  A . smoky exhaust B . starting failure C . ignition relay D . over speed

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• A restricted air intake to a diesel engine may result in the engine （）.

  A . failing to reach rated speed B . knocking under maximum load C . hunting or surging under light load D . overspeeding and running away

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• Worn diesel engine intake valve guides can result in （）

  A . increased engine breathing efficiency B . excessive valve lash C . excessive lube oil consumption D . lower than normal fuel consumptio

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• In a diesel engine, blow-by（）

  A . increase exhaust back pressure B . causes excessive crankcase pressure C . can only be detected by a compression check D . decreases fuel consumptio

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