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单选题
When fuel enters the crankcase of a diesel engine, it （）
A
dilutes the lube oil and reduces its viscosity
B
forms sulfuric acid in the lube oil
C
causes pitting and failure of the bearings
D
causes sludge deposits on valve stems
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考题
Crankcase explosions in propulsion diesel engines result from ____.A.the splashing of lubrication oil by the crankshaftB.the dilution of crankcase oil with particles of combustionC.broken fuel lines spraying oil on the crankcaseD.the ignition of unburned fuel and air in the crankcase
考题
When fuel is injected late into a diesel engine cylinder_______.A.the exhaust will be clearB.fuel consumption will be lowC.all the fuel will be burned at top dead centerD.fuel consumption will be high
考题
单选题Which of the listed problems would be indicated by an accumulation of water in one cylinder, in addition to the crankcase of an idle diesel engine?（）A
Excessive cylinder linerB
water in the fuel systemC
Cracked cylinder linerD
Leaking lube oil cooler
考题
单选题Before starting a diesel engine, you should always（）A
check the pyrometer readingsB
check the crankcase oil levelC
check the fuel oil strainersD
clean the fuel system
考题
单选题When the opening pressure of a diesel fuel injector is greater than that specified by the engine manufacturer，the （）A
quantity of fuel injected is decreasedB
quantity of fuel injected will always be increasedC
start of injection is advancedD
duration of injection will always be greater
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 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When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?（）A
Quantity of fuel injected tends to be decreasedB
Quantity of fuel injected will always be increasedC
Start of injection tends to be advancedD
Duration of injection will always greater
考题
单选题Which of the following conditions is most likely to occur when unburned fuel contaminates the crankcase of a diesel engine?（）A
Lube oil is diluted and its viscosity is reducedB
Sulfuric acid is formedC
Bearings become pitted ad immediately failD
Valve stems develop sludge deposits
考题
单选题Starting a large low-speed propulsion diesel engine on diesel fuel during cold weather conditions, will be made easier by （）A
increasing the quantity of starting airB
increasing the lube oil pressureC
heating the engine fuel supplyD
heating the engine coolant
考题
单选题When fuel oil has seriously contaminated a diesel engine lubricating oil, you should （）.A
filter to remove the fuel oilB
use the settler to remove the fuel oilC
remove the fuel oil by centrifugingD
drain and then renew the lube oil supply
考题
单选题When fuel is injected late into a diesel engine cylinder,（）.A
the exhaust will be clearB
fuel consumption will be lowC
all the fuel will be burned at top dead centerD
fuel consumption will be high
考题
单选题What color exhaust will be exhibited when a slow speed two-stroke/cycle main propulsion diesel engine, designed to operate on light and heavy fuel oil, is operated on insufficiently preheated heavy fuel oil?（）A
WhiteB
BlackC
BlueD
Clear
考题
单选题In a diesel engine, blow-by（）A
increase exhaust back pressureB
causes excessive crankcase pressureC
can only be detected by a compression checkD
decreases fuel consumption
考题
单选题The fuel from the bunker tanks must be treated by before entering the service tanks（）, from where the fuel enters（）A
centrifugal separators; the engine cylinderB
oily water separators; the engine cylinderC
oily water separators; the fuel supply systemD
centrifuges; the fuel supply system
考题
单选题Crankcase explosions in propulsion diesel result from（）A
the splashing of lubrication oil by the crankshaftB
the dilution of crankcase oil with particles of combustionC
broken fuel lines spraying oil on the crankcaseD
the ignition of unburned fuel and air in the crankcase
考题
单选题If a crankcase explosion occurs in a diesel engine, you should stop the engine and（）A
immediately open all crankcase relief portsB
increase crankcase exhauster speed to draw cool air into the engineC
allow the engine to cool naturallyD
increase crank case scavenge air to remove unburned gases
考题
单选题Significant retardation of a diesel engine fuel injection timing will result in （）A
smoother engine operationB
advanced fuel ignitionC
increased fuel economyD
reduced engine power
考题
单选题A diesel engines crankcase oil level is found to be too high√ You should suspect that （）.A
the engine was over filledB
there might be a fuel leakC
there might be a water leakD
all of the above
考题
单选题In a normally operating diesel engine, the main cause of lubricating oil contamination in the crankcase is a result of the （）.A
metal particles loosened by wearB
air when no air cleaners are usedC
condensation of water vaporsD
breakdown of the lubricating oil by dilution
考题
单选题When the load is increased on a turbocharged diesel engine, the amount of increased air supplied by the turbocharger will（）A
lag behind the increased fuel supplied to the engineB
enter the engine along with the increase in the fuelC
enter the engine before the increased fuel supplyD
leave the turbocharger as a negative pulse
考题
单选题When fuel is injected in a diesel engine cylinder too early, （）A
ignition may be delayedB
fuel economy is not affectedC
exhaust gas temperature will be unchangedD
the exhaust will be clear
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 crankcase explosion occurs in a diesel engine, which of the listed actions should be taken?（）A
Open the crankcase immediately to check for damageB
Apply fire fighting water through the crankcase breatherC
Allow the engine to cool before opening the crankcaseD
Assume that there is no damage to the crankshaft
考题
单选题A diesel engine burns （） a gasoline engine of the same capacity in the same period of time.A
as much fuel asB
less fuel thanC
less fuel asD
more fuel than
考题
单选题When running a large, low-speed, main propulsion diesel engine on heavy fuel, which of the following precautions should be observed when switching back over to diesel oil?（）A
The diesel oil must never be allowed to mix with the heavy fuelB
The temperature of the fuel from the pre–heater should be gradually reduced after switching over the three–way valveC
The heating steam to the pre-heater should be secured as soon as the diesel fuel passes through the three-way valveD
The heating steam must be secured before the diesel oil passes through the three-way valve
考题
单选题The breaking-up of fuel as it enters a diesel engine cylinder is known as（）A
airificationB
vaporizationC
atomizationD
gasification
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