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The purpose of the skirt or trunk in four-stroke cycle engines is to act in a similar manner to a ().
A . crosshead
B . crown
C . piston rod
D . connecting rod
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The camshaft on a four-stroke/cycle diesel engine provides a means to operate the ().
A . fuel injectors
B . exhaust valves
C . intake valves
D . all of the above
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A connecting rod in a four-stroke/cycle diesel engine is subject to()
A . tension load twice each crankshaft revolution
B . compression load during power and compression strokes
C . inertia load once every four crankshaft revolutions
D . bending loads at bottom and top dead center
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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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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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During the valve overlap period, the exhaust pressure of a turbochargers, four-stroke/cycle diesel engine must be less than the intake manifold pressure to ensure ()
A . effective cylinder scavenging and cooling
B . constant pressure from the turbochargers
C . cooler operation of the exhaust system
D . effective constant pressure for turbocharger operatio
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What is the crank angle between any two crank throws in the firing order of a four-stroke/cycle, in line, eight cylinder diesel engine?()
A . 45
B . 60
C . 90
D . 100
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Air motion is induced in a four-stroke/cycle diesel engine cylinder to improve air fuel mixing, and is known as()
A . supercharging
B . scavenging
C . turbulence
D . swept volume charging
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If a four-stroke/cycle diesel engine is started by injecting air into the cylinder, the pistons receiving the charge of starting air must be()
A . on the power stroke
B . on the exhaust stroke
C . at the end of the power stroke
D . at the start of the intake stroke
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Scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished()
A . during the valve overlap period
B . with only the exhaust valve open
C . at a pressure below atmospheric
D . without cooling the cylinders or pisto
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A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine()
A . has little or no internal friction
B . has a lower effective compression ratio
C . operates with scavenge air under a positive pressure
D . operates without energy absorbing intake and exhaust stroke
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Clearance volume scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished ().
A . during the valve overlap period
B . with only the exhaust valve open
C . at a pressure below atmospheric
D . without cooling the cylinders or pisto
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In a four-stroke/cycle diesel engine, badly worn intake valve guides can cause excessive().
A . exhaust pressure
B . exhaust temperatures
C . cooling water temperatures
D . lube oil consumptio
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If the turbocharger of a four-stroke/cycle diesel engine fails to operate, which of the following statements best describes the probable effect?()
A . Intake manifold pressure will be high
B . Intake manifold pressure will be unaffected
C . Exhaust temperatures will be high
D . Exhaust temperatures will be low
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Which of the following statements is correct regarding a turbocharged four-stroke/cycle diesel generator?()
A . At zero load the intake manifold pressure is greater than the exhaust manifold pressure
B . At full load the intake manifold pressure and exhaust manifold pressure are equal
C . At full load the intake manifold pressure is less than the exhaust manifold pressure
D . At full load the intake manifold pressure is greater than the exhaust manifold pressure
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High exhaust temperatures from all of cylinder of a turbocharged, four-stroke/cycle diesel engine can be caused by an()
A . inoperative turbocharger
B . inadequate fuel supply
C . overload on one cylinder
D . unequal load distributio
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In a closed cooling system for a turbocharged, four-stroke/cycle diesel engine, fluctuating water pressure can be caused by ()
A . improper venting of the cooling system
B . carrying the expansion tank water level too high
C . a totally clogged impeller in the cooling water pump
D . an incorrectly set cooling system temperature control
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In a four-stroke/cycle diesel engine, after the completion of the power stroke, the piston will move()
A . up and draw in a fresh air charge
B . down to burn off fuel
C . down to compress the fuel air charge
D . up and force out the exhaust gase
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During the power stroke of a four-stroke/cycle diesel engine, most of the side thrust of a trunk-type piston is absorbed by the()
A . piston skirt
B . pinion
C . crosshead
D . compression ring
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In a four-stroke/cycle diesel engine, the camshaft rotates at ()
A . twice the crankshaft speed
B . half the crankshaft speed
C . the same speed as that of the crankshaft
D . a speed independent of that of the crankshaft
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Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because ()
A、a circulating system; a total loss system
B、a total loss system; a circulating system
C、an opened system; a closed system
D、a closed system; an opened system
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Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because().
A . The direction of pressure on the journal in four-stroke engine is continuously
B . positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
C . four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
D . Low-stroke engines usually consume less lube oil than four-stroke engine
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A disadvantage of a four-stroke/cycle diesel engine is ()
A . higher working temperature of piston and cylinder
B . the use of scavenge ports
C . fewer power strokes per revolution of the crankshaft
D . part of the fuel is burned as the piston is moving away from top dead center
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What is the speed of the crankshaft in a four-stroke/cycle engine when the camshaft is turning at 750 rpm?()
A . 375 RPM
B . 500 RPM
C . 750 RPM
D . 1500 RPM