更多"An electric heater built into some "的相关试题:
[单项选择]Why are some diesel engine cylinder liners plated on the wearing surface with porous chromium?（）
A. The chromium will not wear out the piston rings
B. The chromium strengthens the liners in the way of the scavenging air ports
C. Chromium eliminates the need for oil scraper rings
D. Pores in the plating aid in maintaining the lube oil film
[单项选择]Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinderIf the cooling water temperature from all cylinders begins to rise above normal, you should suspect （）
A. increase blow-by in all cylinders
B. incomplete combustion in all cylinder
C. overloading in all cylinders
D. insufficient fuel delivery to all cylinders
[单项选择]The interior of some diesel engine saltwater heat exchangers are protected from corrosion by the use of（）
A. aluminum plates
B. lead cathodes
C. copper baffle plates
D. sacrificial zincs
[单项选择]Some diesel engines are supercharged with a （）
A. slam charger
B. turbocharger
C. fuel atomizer
D. fuel injector
[单项选择]Valve cages are used on some large diesel engines to （）
A. reduce wear on the valve stem
B. permit the use of alloy valve seat materials
C. reduce heat transfer from the valve seat
D. facilitate valve removal for servicing
[单项选择]Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）
A. must churn the oil in the sump
B. is connected to the propeller shaft
C. is driven at the highest RPM
D. compensates for alignment variations between the engine and pinion gear
[单项选择]A waste heat boiler is installed on some diesel propelled vessels to （）.
A. provide steam for emergency propulsion
B. provide steam for the turbo-generator
C. heat the waste water tanks
D. steam for warming engines
[单项选择]In some modern large diesel engines, which of the following is used as the support for the main bearings?（）
A. Bedplate
B. Block
C. Base
D. Sump
[单项选择]In some diesel engine designs,（）the injection of cylinder oil is timed to impinge when the piston and only impinge on（）
A. is coming upward；cylinder ring belt
B. is going downward；piston ring belt
C. is coming upward；piston ring belt
D. is going downward；cylinder ring belt
[单项选择]The marine diesel engine is a type of diesel engine used on ships The （） of its operation is not very difficult to understand.
A. principle
B. principal
C. cause
D. case
[单项选择]Diesel oil may be used to cool （） of a diesel engine.
A. cylinders
B. exhaust valves
C. pistons
D. fuel valves
[单项选择]Mechanical lubricators for diesel engine cylinders are usually small reciprocating pumps which are （）.
A. operated manually once an hour
B. operated until the engine has started
C. placed into operation only at maximum load
D. adjustable to meet lubrication requirements
[单项选择]Diesel engine mufflers accomplish noise reduction by （）
A. reducing exhaust gas velocity
B. increasing the frequency of gas vibration
C. the use of long head pipes
D. the use of zinc electrodes
[单项选择]Diesel fuel vapors （）.
A. can not be ignited by a spark unless the vapor is in a confined space
B. are nontoxic in all concentrations
C. can not be ignited by a spark unless they are at their auto-ignition temperature
D. are heavier than air
[单项选择]An emergency diesel generator should automatically shut down in the event of （）
A. dangerous over-speeding
B. a loss of lube oil pressure
C. activation of the fixed CO2 system for the emergency generator space
D. all of the above
[单项选择]The main purpose of an electric space heater installed in a large AC generator is to （）
A. prevent the windings from becoming brittle
B. prevent moisture from condensing in the windings during shutdown
C. prevent acidic pitting of the slip rings
D. keep the lube oil warm for quick starting
[单项选择]A heater in the circuit facilitates warning of the engine prior to （） by circulating hot water.
A. starting
B. stopping
C. to start
D. to stop
[单项选择]Diesel engine fuel oil contamination often results in （）
A. governor malfunctions
B. fuel injection system malfunctions
C. high cylinder lube oil temperatures
D. low intake temperatures
[单项选择]Diesel engine crankshaft deflection readings are generally taken at four crank positionsGood engineering practice requires the deflection gage or indicator to be（）
A. placed as near the crankpin axis as possible
B. removed each time the crankshaft is repositioned
C. left in place for all four readings
D. reset to zero for all four readings
