更多"The closing of the exhaust valves u"的相关试题:
[单项选择]In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low alloy steels because （）.
A. the beveled edges of the intake valves provide for serf-centering during seating
B. intake valves utilize stellite-coated valve seat inserts which reduce wear
C. the volume of air passing through intake valves is less than the volume of air passing through exhaust valves
D. intake valves are less affected to the corrosive action of exhaust gases
[单项选择]Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to （）
A. provide added wear protection against today’s corrosive quality of fuel
B. increase overall valve strength due to the high gas pressures
C. assist in dissipating heat due to the extreme operating temperatures
D. reduce the overall weight of the valve thus helping eliminate valve spring surge and hammering
[单项选择]
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
[单项选择]What is the purpose of the intake/exhaust valves in a diesel engine? （）
A. They regulate the combustion cycle
B. They supply cooling water
C. They synchronize the ignition spark
D. They supply and regulate the lubricant flow
[单项选择]The exhaust boilers are used to recover some of （） carried in the exhaust gas from the main engine.
A. water
B. oil
C. heat
D. steam
[单项选择]Differential needle valves used in fuel injectors are directly closed by（）
A. cam action
B. spring force
C. fuel oil pressure
D. firing pressure
[单项选择]Diesel engine exhaust temperatures may be used to indicate （）.
A. leaking exhaust valves
B. an overloaded cylinder
C. a clogged injector nozzle
D. all of the above
[单项选择]The series of valves used to control the return flow in well control operations is called the（）.
A. valve assembly
B. standpipe manifold
C. accumulator manifold
D. choke manifold
[单项选择]The period when both inlet valves and exhaust valves are open is referred to as （）.
A. valve loop
B. valve uniflow
C. valve overlap
D. valve grinding
[单项选择]Diesel engine exhaust gas temperatures can be used to determine individual cylinder （）.
A. performance
B. horsepower output
C. fuel consumption
D. scavenge effect
[单项选择]Which of the valves listed should be used either in the fully opened or the fully closed position?（）
A. A gate valve
B. A globe valve
C. Any check valve
D. Any needle valve
[单项选择]Modern engines （） exhaust gas driven turbo-chargers to supply pressurized fresh air for scavenging and supercharging.
A. are made of
B. are made from
C. make use of
D. are used to
[单项选择]（）is a caing used for exhaust pipe from the engines.
A. The funnel
B. The messroom
C. The galley
D. The satellite antenna
[单项选择]（）is not used in modern radar.
A. EBL
B. VRM
C. CRT
D. Grease pencil
[单项选择]Additional heat extraction from the exhaust gases can be effected by adding an （） section to the unit in plants.
A. air cooler
B. economizer
C. injector
D. air blower
[单项选择]High exhaust temperature and black smoke exhausting from an auxiliary diesel engine can be caused by （）.
A. engine overload
B. low combustion temperature
C. plugged fuel nozzle holes
D. excessive compression pressure
[单项选择]Pyrometers commonly found on diesel engine exhaust systems, consist of（）
A. pyrostats and a voltmeter
B. a gas-filled bellows, a tube and a pressure gauge
C. thermocouples and a voltmeter
D. ammeters and thermocouples
[单项选择]Exhaust pyrometer readings provide an indication of the （）
A. effectiveness of water-cooled exhaust elbows
B. distribution of the load between engine cylinders
C. amount of fuel penetration into the engine cylinders
D. indicated horsepower of the engine cylinders
[单项选择]The rising of the exhaust temperature in manifold pipe may NOT result from （）.
A. too great a loading
B. fouled turbocharger
C. bad combustion
D. excessive air
