73.The purpose of counterboring the top of the cylinder liner, extending down to the top point of travel of the top compression ring, is to _____________.
A.increase cylinder turbulence.
B.prevent wear of the liner from occurring.
C.prevent wear of the liner from forming a ridge at the upper level of ring travel
D.decrease compression ratio for easier starting
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]C.prevent wear of the liner from forming a ridge at the upper level of ring travel[/bg_collapse]
74.The most rapid period of fuel combustion in a diesel engine cylinder should begin just before the piston reaches top dead center and ____________.
A.when fuel injection has been completed
B.when fuel vaporization has been completed
C.should efficiently continue through the after burning period in all properly designed engines
D.should be completed shortly after passing top dead centerAns:CAns:D
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.should be completed shortly after passing top dead center[/bg_collapse]
75.Exhaust gas pyrometers are useful for ____________.
A.detecting faulty combustion in individual cylinders
B.adjusting fuel racks to maintain equal loading between cylinders
C.adjusting the load limit setting of the governor at idle conditions
D.calculating engine horsepower
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.detecting faulty combustion in individual cylinders[/bg_collapse]
76.Oil control rings function to _____________.
A.allow proper lubrication of cylinders and compression rings
B.reduce the amount of lube oil burned in the combustion chamber
C.scrape excess lube oil from the liner on the downstroke
D.all of the above
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.all of the above[/bg_collapse]
77.In the construction of a diesel engine, what is the purpose of end plates?
A.To provide accessibility to the cylinder liners.
B.To add rigidity to the block and a surface for attaching other parts.
C.To add stability to the engine block.
D.To make a surface for the base.
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]B.To add rigidity to the block and a surface for attaching other parts.[/bg_collapse]
78.The main purpose of the piston oil scraper rings is to _____________.
A.seal the space between the piston and the liner
B.reduce the amount of lube oil burned in the combustion chamber
C.transmit heat from the piston to the cylinder liner
D.damp out fluctuations of the piston side thrust
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]B.reduce the amount of lube oil burned in the combustion chamber[/bg_collapse]
79.What is commonly used to create turbulence in a diesel engine combustion system?
A.Shape of the piston crowns.
B.Increasing the compression ratios.
C.Increasing the effective plunger stroke.
D.Increasing the turbocharger gear ratio.
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]A.Shape of the piston crowns[/bg_collapse]
80.How many power strokes per crankshaft revolution are there in an eight cylinder, two-stroke/cycle diesel engine?
A.One
B.Two
C.Four
D.Eight
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]D.Eight[/bg_collapse]
81.To shut down a diesel engine after it exceeds the set maximum speed, which type of device listed should be used?
A.Speed limiting governor
B.Overspeed governor
C.Overspeed trip
D.Overspeed relay
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]
C.Overspeed trip
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82.Turbulence is created in the cylinders of a diesel engine to _____________.
A.obtain injection lag
B.help mix fuel and air
C.increase combustion pressure
D.utilize higher injection pressures
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]
B.help mix fuel and air
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83.To function properly, oil control rings used on a diesel engine piston must distribute sufficient oil to all parts of the cylinder wall and must also _____________.
A.prevent any lubricant from reaching the compression rings
B.prevent excessive lubrication from reaching the combustion space
C.provide metal-to-metal contact to seal the cylinder against blow-by
D.assure a positive means of scraping carbon accumulation from the cylinder
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]
B.prevent excessive lubrication from reaching the combustion space
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84.An important design characteristic of an explosion relief valve for a diesel engine is the ability to _________.
A.close quickly in order to prevent an inrush of air
B.open quickly against crankcase pressure to prevent a possible implosion
C.open slowly to permit a gradual reduction of crankcase pressure
D.close slowly to permit proper seating of the valve disc and neoprene sealing surfaces
[bg_collapse view=”button-orange” color=”#49494a” expand_text=”View Answer” collapse_text=”Hide Answer” ]
A.close quickly in order to prevent an inrush of air
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