更多"The mechanical exhaust valve operat"的相关试题:
[单项选择]The exhaust system for a turbocharged diesel engine functions to （）
A. power the after-coolers
B. power the turbocharger
C. reduce the cylinder scavenge effect
D. cool the turbocharger
[单项选择]Exhaust system的中文含义是（）。
A. 排气系统
B. 进气系统
C. 转向系统
D. 燃油喷射系统
[单项选择]（） are fitted in the exhaust system and facilitate charge removal and scavenging in each cylinder.
A. Diffusers
B. Compressors
C. Steam boilers
D. Soot blowers
[单项选择]In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in （）
A. increased engine back pressure
B. sulfuric acid corrosion
C. surface pitting of the turbocharger
D. moisture impingement on the turbocharger compressor blade
[单项选择]The exhaust system of a diesel engine is usually designed to remove exhaust gases and to （）
A. provide exhaust back pressure
B. prevent exhaust smoke emissions
C. power a reciprocating supercharger
D. muffle exhaust gas noise
[单项选择]The exhaust system for a turbocharged two-stroke/cycle diesel engine functions to（）
A. discharge exhaust gases and smoke
B. furnish energy to the turbocharger
C. reduce engine room noise
D. all of the above
[单项选择]
The exhaust valve opens before bottom dead center in a four stroke engine to（）
Ⅰ.allow for blow down
Ⅱ.Reduce pumping losses
A. Ⅰ only
B. Ⅱ only
C. both Ⅰ and Ⅱ
D. neither Ⅰ nor Ⅱ
[单项选择]Icreasing the exhaust valve tappet clearance of a diesel engine will result in the exhaust valve opening （）
A. later and closing earlier
B. later and closing later
C. earlier and closing earlier
D. earlier and closing later
[单项选择]Exhaust valve openings in a diesel engine cylinder head are made as large as practical to （）
A. increase back pressure during the exhaust process
B. facilitate periodic replacement of the valves
C. reduce the pumping loss associated with scavenging
D. reduce tension on valve springs
[单项选择]Exhaust valve grooving and corrosion is caused by certain components of residual fuel oilThese components are sodium, sulfur, and （）.
A. vanadium
B. carbon
C. copper
D. ash
[单项选择]Aburned exhaust valve may be detected by a higher than normal （）
A. firing pressure
B. exhaust temperature from a particular cylinder
C. cooling water temperature
D. compression pressure
[单项选择]
Leaky exhaust valve will result in which of the following?（）
(1) high exhaust temperature;
(2) low compression pressure;
(3) low firing pressure.
A. (1) and (2)
B. (1) only
C. (2) only
D. (1),(2) and (3)
[单项选择]The size of the exhaust valve opening is （）
A. most critical in a four-stroke cycle diesel engine
B. most critical in a two-stroke/cycle diesel engine
C. most critical in a four-stroke/cycle diesel engine if it is turbocharged
D. of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
[单项选择]The exhaust valve is opened at about the same time （） the air inlet ports are opened.
A. before
B. after
C. when
D. until
[单项选择]The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by （）.
A. direct action of cam shaft
B. compressed air pressure
C. hydraulic “push rods”
D. direct action of the main piston moving down
[单项选择]A built-up exhaust valve is one in which （）.
A. the stem and heads are made of different material
B. low-alloy steel is used throughout
C. a replaceable valve disk is welded to the head
D. the self-centering action comes from motion of the valve stem in the guide
[单项选择]During the valve overlap period, the exhaust pressure of a turbochargers, four-stroke/cycle diesel engine must be less than the intake manifold pressure to ensure （）
A. effective cylinder scavenging and cooling
B. constant pressure from the turbochargers
C. cooler operation of the exhaust system
D. effective constant pressure for turbocharger operation
[单项选择]In an engine with air inlet valve and exhaust valve on its cylinder heads the fresh air will enter into the cylinder （） and the gases exhaust （）, there being an adequate overlap between the inlet opening and the exhaust closing.
A. downwards；upwards
B. upwards；downwards
C. downwards；downwards
D. upwards；upwards
[单项选择]In the starting system, the automatic valve is controlled by（）, and the cylinder start valves are controlled by（）
A. pilot air；pilot air
B. handle；solenoid
C. handle；pilot air coming through the distributor
D. solenoid；pilot air coming through the distributor
