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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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Cooling the intake air supplied to a diesel engine will （）.
A . reduce mean effective pressure
B . decrease average compression pressure
C . decrease air charge density
D . increase power output
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An indication of a diesel engine air intake being partially clogged, is （）.
A . low firing pressure and low exhaust temperatures
B . low firing pressure and normal exhaust temperatures
C . high firing pressure and low exhaust temperatures
D . high firing pressure and high exhaust temperature
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Excessively worn, or polished ends on a diesel engine valve spring, indicate（）
A . burned exhaust valves
B . excessive spring compression
C . spring surge
D . worn valve seat
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The intake ports of a two-strike/cycle diesel engine are opened and closed by the action of the （）
A . camshaft
B . piston movement
C . exhaust valves
D . vertical drive
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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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Higher than normal temperature air passing through the intake of a diesel engine will result in（）
A . greater overall efficiency
B . greater fuel economy
C . lower horsepower
D . lower compression ratio
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Because of the close tolerances used in diesel engine fuel oil pumps, a worn plunger requires（）
A . grinding the spare plunger to the barrel
B . replacing the plunger and the barrel
C . highly polishing both the plunger and barrel
D . replacing plunger only
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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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The intake valves in a diesel engine are reseated by （）.
A . cam followers
B . push rods
C . combustion gases
D . valve spring
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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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On a turbo-charged, medium-speed diesel engine, which of the following problems is an indication of a restricted air intake passage?（）
A . Engine is hard to start
B . Engine misses
C . Surges at governed RPM
D . Coolant temperature is too low
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Worn main bearing will cause the compression ratio of an auxiliary diesel engine to（）
A . increase
B . decrease
C . remain the same
D . increase on compression decrease on expansio
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In a diesel engine, blow-by is generally the result of worn（）
A . valve guides
B . oil control rings
C . valve seats
D . compression ring
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What is the function of the after-cooler installed in the diesel engine air intakes system?（）
A . Decrease the air density
B . Increase the exhaust temperature
C . Decrease the lube oil temperature
D . Increase the air density
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A turbocharged diesel engine will have an intake manifold pressure（）
A . constantly decreasing as engine load increase
B . constantly increasing as the amount of supercharging increases
C . approximately equal to exhaust manifold pressure at all times
D . approximately equal to atmospheric pressure at all time
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A naturally aspirated diesel engine at full throttle will have an intake manifold pressure （）
A . slightly less than atmospheric pressure
B . approximately equal to exhaust manifold pressure at all times
C . that is widely fluctuating constantly
D . decreasing as engine load increase
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In a diesel engine, exhaust valves open before the intake ports are uncovered to （） Ⅰ.reduce pumping losses Ⅱ.reduce back pressure
A . Ⅰonly
B . Ⅱonly
C . bothⅠand Ⅱ
D . neitherⅠnor Ⅱ
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Which of the following conditions can cause below normal air pressure in the intake manifold of a turbocharged diesel engine?（）
A . Excessive piston blow-by to the manifold
B . Insufficient cooling water flow
C . Accumulated water in the air boxes
D . Clogged air intake filter
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Diesel engine starting difficulties due to cold intake air temperatures, can be overcome by using a/an（）
A . increase in starting air pressure
B . increase in lube oil viscosity
C . compression expansion device
D . jacket water heater
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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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What is the effect of heated intake air on a diesel engine? （）
A . Increases efficiency
B . Increases engine horsepower
C . Increases engine life
D . Reduces engine horsepower
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The function of the after-cooler installed between the turbocharger and intake manifold on some diesel engine, is to （）
A . increase the density of the intake air
B . decrease turbocharger power usage
C . reduce exhaust gas temperature
D . compensate for turbocharger PRM fluctuatio
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In order to keep excess oil from the intake ports in two-stroke/cycle diesel engines, ________.
A.wide compression rings are used
B.oil rings are located above the piston
C.chromium plating is used on all piston rings
D.oil rings are located near the bottom of the piston skirt
