更多"The opening of an exhaust valve on "的相关试题:
[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 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]The mechanical exhaust valve operation system is replaced by（）in an electronic controlled ME engine.
A. a system with a Hydraulic Power Supply (HPS) unit
B. a system with roller guides for exhaust valves
C. a system with an electronically controlled Alpha Lubricator
D. a system directly powered by electric motor
[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 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]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]Modem engines make use of exhaust gas driven turbo-chargers to supply pressurized fresh air for （） and supercharging.
A. scavenging
B. starting
C. cooling
D. blowing
[单项选择]Modem engines （） exhaust gas driven turbo-chargers to supply pressurized fresh air for scavenging and supercharging.
A. make use of
B. have made the use of
C. by means of
D. make advantage of
[单项选择]A fuel injection valve opening at pressure lower than normal will result in（）.
A. late fuel injection
B. early fuel injection
C. high exhaust temperature from that cylinder
D. decreased effective stroke from that 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]A large valve，usually installed above the ram preventers，that forms a seal in the annular space between the pipe and wellbore or，if no pipe is present，on the wellbore itself is called the（）.
A. annular blowout preventer
B. annulus
C. accumulator
D. automatic choke
[单项选择]In each cylinder cover is a large central opening for mounting （）
A. the indicating cock
B. the starting valve
C. air inlet valve
D. the exhaust valve
