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单选题
When the normal compression ratio of a diesel engine is not very high, misfiring at light loads may be caused by （）
A
overloading the engine
B
low exhaust valve lift
C
excessive cylinder cooling
D
insufficient mechanical clearance
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更多 “单选题When the normal compression ratio of a diesel engine is not very high, misfiring at light loads may be caused by （）A overloading the engineB low exhaust valve liftC excessive cylinder coolingD insufficient mechanical clearance” 相关考题
考题
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 ignitionB.compression must be low for required horsepower and torque generationC.compression must be low to prevent pre-ignitionD.compression must be low to have effective pre-ignition
考题
When using a fuel with a higher than normal sulfur content in an auxiliary four stroke diesel engine, you mayA.maintain higher than normal jacket water temperatureB.change the lube oil more frequently than normalC.maintain a higher air-box temperature than normalD.maintain a higher air-box pressure than normal
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单选题（）are increasingly used as main engine on merchant vessels, because they have a high Hp/Weight ratio.A
Slow speed diesel enginesB
Medium-speed diesel enginesC
Steam enginesD
Gasoline engines
考题
单选题A supercharged diesel engine when compared to a similar naturally aspirated diesel engine, will develop an increase in （）A
ignition lagB
engine horsepowerC
lube oil system pressureD
specific fuel consumption
考题
单选题The ignition of the fuel in diesel engine is caused by the （） of compression of the air previously admitted into the cylinders.A
vacuum pressureB
specific gravityC
heatD
viscosity
考题
单选题Worn main bearing will cause the compression ratio of an auxiliary diesel engine to（）A
increaseB
decreaseC
remain the sameD
increase on compression decrease on expansion
考题
单选题Which of the following operating conditions can occur when shims are removed from the joint between the foot of a marine type diesel engine connecting rod and the bearing box?（）A
Decreased connecting rod bearing clearanceB
Increased connecting rod bearing clearanceC
Decreased compression ratioD
Increased compression ratio
考题
单选题The knock occurring when a cold diesel engine is started and continues while running at low speed, but stops when the engine reaches normal operating speed and temperature, is（）.A
caused by retarded injection timingB
caused by a mechanical defect in one cylinderC
caused by high fuel injection pressuresD
normal for these conditions
考题
单选题What is commonly used to create turbulence in a diesel engine combustion system?（）A
Shape of the piston crownsB
Increasing the compression ratiosC
Increasing the piston crownsD
Increasing the turbocharger gear ratio
考题
单选题When a diesel engine is operate at partial load, as compared to full load ,a decrease will occur in the average （）A
air quantity aspiratedB
fuel injection pressureC
combustion pressure on the power strokeD
compression on the compression stroke
考题
单选题If the compression ratio is increased on any diesel engine, （）A
the expansion ratio will decreaseB
combustion will be slowed downC
thermal efficiency will decreaseD
thermal efficiency will increase
考题
单选题If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will （）A
open late and close earlyB
open late and close lateC
fail to open when the engine is coldD
fail to open at normal operating temperature
考题
单选题Proper atomization of fuel in diesel engine combustion chambers will （）.A
affect the injection pressureB
improve combustionC
reduce compression pressureD
decrease power output
考题
单选题The ratio of the brake horsepower to the indicate of a diesel engine is its （）A
thermal efficiencyB
mechanical efficiencyC
brake thermal efficiencyD
volumetric efficiency
考题
单选题The arrangement and shape of the cams on a diesel engine camshaft directly control which of the listed groups of operating conditions?（）A
speed, torque, and horsepower productionB
firing order, valve timing, and valve liftC
fuel consumption, efficiency, and cylinder pressureD
scavenge pressure, compression ratio, and exhaust pressure
考题
单选题For a given fuel, a change in the compression ratio will affect the ignition lag by which of the listed means?（）A
An increase in compression ratio will increase the ignition lagB
An increase in compression ratio will decrease the ignition lagC
A decrease in compression ratio will decrease the ignition lagD
A decrease in ignition lag will increase the compression ratio
考题
单选题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 frictionB
has a lower effective compression ratioC
operates with scavenge air under a positive pressureD
operates without energy absorbing intake and exhaust strokes
考题
单选题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 ignitionB
compression must be low for required horsepower and torque generationC
compression must be low to prevent pre-ignitionD
compression must be low to have effective pre-ignition
考题
单选题When a diesel engine compression pressure is checked, the indicator is connected to the （）A
cylinder exhaust portsB
injection lineC
cylinder indicator cockD
banjo oiler line
考题
单选题The function of diesel engine piston compression rings is to （）.A
prevent piston side thrustB
prevent engine friction lossesC
transmit heat from the piston to the cylinder linerD
remove oil from the cylinder combustion space
考题
单选题Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?（）A
Higher compression ratios create higher temperatureB
Higher temperatures create higher compression ratiosC
low temperatures create higher compression ratiosD
Higher compression ratios create low temperatures
考题
单选题When restarting a heavy fuel diesel engine that has been stopped for some time, the engine should（）A
increase the starting air pressureB
use a higher than normal cranking speedC
increase the fuel injection pressureD
use a fuel having a lower ignition temperature
考题
单选题If a diesel engines exhaust temperature is abnormally high, the cause could be（）A
too light of a loadB
injection timing is too earlyC
overloading of the engineD
too low of a compression ratio
考题
单选题Higher than normal temperature air passing through the intake of a diesel engine will result in（）A
greater overall efficiencyB
greater fuel economyC
lower horsepowerD
lower compression ratio
考题
单选题A four-stroke/cycle, 1000horsepower diesel engine fails to start at normal cranking speed with normal fuel pressure and ambient temperatureThe reason for the failure could be（）A
glazed liners or pistonsB
high lube oil pressureC
excessive compression ratioD
worn valve seats and valves
考题
单选题When using a fuel with a higher than normal sulfur content in an auxiliary diesel engine, you should（）A
maintain higher than normal jacket water temperatureB
change the lube oil more frequently than normalC
maintain a higher air-box temperature than normalD
maintain a higher air-box pressure than normal
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