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

C.prevent wear of the liner from forming a ridge at the upper level of ring travel

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

D.should be completed shortly after passing top dead center

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

A.detecting faulty combustion in individual cylinders

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

D.all of the above

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.

B.To add rigidity to the block and a surface for attaching other parts.

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

B.reduce the amount of lube oil burned in the combustion chamber

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.

A.Shape of the piston crowns

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

D.Eight

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

C.Overspeed trip

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

B.help mix fuel and air

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

B.prevent excessive lubrication from reaching the combustion space

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

A.close quickly in order to prevent an inrush of air

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