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Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can ______.
A.increase power output
B.decrease lube oil viscosity
C.eliminate fuel knock
D.cause sulfuric acid formation
参考答案
更多 “ Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can ______.A.increase power outputB.decrease lube oil viscosityC.eliminate fuel knockD.cause sulfuric acid formation ” 相关考题
考题
If the coolant temperature of a closed cooling water system for a diesel enginegradually increases, the trouble usually is( ).A.a broken shaft on the freshwater pumpB.an excessive accumulation of scale in the heat exchangerC.an incorrect thermostatic element operating rangeD.lube oil in the cooling water
考题
In a diesel engine closed freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the __.A.suction pressure regulatorB.thermostatic bypass valveC.sea water temperatureD.water level in the expansion tank
考题
A two stroke diesel engine exhaust temperature will be lower than a four stroke diesel engine of the same displacement because the _____. ① MEP is lower and the scavenging air is cooling the exhaust gases ② valve overlap in a four strokeA.①B.②C.① and ②D.Neither ① nor ② is correct
考题
High diesel engine cooling water temperatures can be caused by ______.A.air in the cooling systemB.an overhauled water pumpC.correct amount of coolantD.no air in the cooling system
考题
单选题If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is （）A
a broken shaft on the freshwater pumpB
an excessive accumulation of scale exchangerC
an incorrect thermostatic element operating rangeD
lube oil in the cooling water
考题
单选题Lube oil accumulating in the cooling water system of a diesel engine will result in （）A
lube cooler failureB
poor heat transferC
mechanical lubricator failureD
camshaft seizure
考题
单选题Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?（）A
Baffle plates that have been bent during prior removalB
Leaks in the cooler tube nestC
Operating the engine while maintaining a high sea water outlet temperatureD
A punctured sea water strainer supplying cooling water to the heat exchanger
考题
单选题The device allowing for the change in volume of the cooling water in a propulsion diesel engine closed cooling system is the （）.A
fresh water expansion tankB
sea water expansion tankC
thermostatic expansion valveD
jacket water cooler accumulator
考题
单选题If the jacket water temperature in an auxiliary diesel engine cooling system is lower than normal, the probable cause is （）A
air binding of the engine cooling systemB
a cracked water cooled exhaust manifoldC
blockage in the heat exchangerD
faulty operation of the thermostat
考题
单选题The satisfactory operation of diesel engine exhaust valves usually depends on（）A
the proper back pressureB
the cooling water temperatureC
correct timing and proper seatingD
accurate metering and the exhaust temperature
考题
单选题High diesel engine cooling water temperatures can be caused by （）.A
air in the cooling systemB
an overhauled water pumpC
correct amount of coolantD
no air in the cooling system
考题
单选题In a closed cooling system for a turbocharged, four-stroke/cycle diesel engine, fluctuating water pressure can be caused by （）A
improper venting of the cooling systemB
carrying the expansion tank water level too highC
a totally clogged impeller in the cooling water pumpD
an incorrectly set cooling system temperature control
考题
单选题The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and （）.A
reduce water temperatureB
reduce water turbulenceC
provide an air cushionD
allow for an increase in water volume as the engine warms up
考题
单选题The highest pressure in any closed diesel engine freshwater cooling system is at the （）.A
jacket water outletB
expansion tank inletC
heat exchanger inletD
cooling water pump outlet
考题
单选题In a diesel engine cooling system, the high temperature alarm contact maker will be activated on excessively high water discharge temperature from the （）A
raw water pump dischargeB
expansion tank outletC
cooling water heat exchangerD
outlet engine jacket water outlet
考题
单选题In a diesel engine jacket water cooler, with seawater cooling the fresh water, the（）A
sea water temperature must never be warmer than 40℃B
jacket water pressure should always be greater than the sea water pressureC
jacket water temperature must always be less than 60℃D
jacket water pressure must always be less than the sea water pressure
考题
单选题If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a （）.A
loss of suction in the circulating pumpB
leak in the primary cooling systemC
broken raw water pump shaftD
burned or cracked piston in one cylinder
考题
单选题Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsion diesel engine?（）A
Defective temperature controls in the systemB
Cavitation in the cooling water pumpC
Opened vent in the cooling systemD
Restricted water passages in the engine
考题
单选题In a closed diesel engine freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the （）.A
suction pressure regulatorB
thermostatic bypass valveC
sea water temperatureD
water level in the expansion tank
考题
单选题Temperature control valves installed in the jacket cooling water system of a diesel engine modulates the rate of water flow through the （）.A
cooling water pumpB
nozzle cooling passagesC
cylinder jacketsD
heat exchanger
考题
单选题A diesel engine cooling water system with a pH factor of 30 indicates a condition of （）.A
slight acidityB
slight alkalinityC
excessive alkalinityD
excessive acidity
考题
单选题Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause （）.A
the formation of sulfuric acidB
a decrease in lube oil viscosityC
a decrease in cooling water pHD
a thermostat failure
考题
单选题In any diesel engine closed freshwater cooling system, the lowest pressure exists at the （）.A
jacket water outletB
cooling water pump outletC
heat exchanger outletD
expansion tank atmospheric vent
考题
单选题In a diesel engine cooling water system, a pH of 60 indicates a/an （）.A
slightly acidic conditionB
slightly alkaline conditionC
overtreatment of waterD
neutral condition of water
考题
单选题There is （） in any water cooling system for a diesel engine allowing for expansion and water make-up in the system as well as air vent and chemicals addition.A
a setting tankB
a service tankC
a head tankD
an expansion joint
考题
单选题In the process of the stand-by, warm-up the engine usually through give preheat of which parts of the diesel engine?（）A
cooling water of the cooling systemB
fuel of the FO systemC
LO of the LO systemD
cooling water of the cooling system and LO of the LO system
考题
单选题The jacket water temperature in a diesel engine closed freshwater cooling system is normally controlled by （）A
regulating the level of corrosion inhibitor in the primary cooling systemB
the level of the freshwater expansion tankC
varying the engine load to meet temperature requirementsD
the operation of the thermostatic valve
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