更多"Icreasing the exhaust valve tappet "的相关试题:
[单项选择]Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）
A. closing later
B. opening sooner
C. staying open for a shorter period of time
D. staying open for a longer period of time
[单项选择]Reducing the clearance between a valve stem and rocker arm will result in the valve （）
A. having a shorter duration of opening
B. having a longer duration of opening
C. closing sooner
D. opening later
[单项选择]If you increase the clearance between a valve stem and rocker arm, which of the listed condition will occur?（）
A. valve will open later
B. valves will close later
C. amount of fuel injected will be increased
D. amount of fuel injected will be decreased
[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]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]Valve lash, or clearance refers to the （）
A. clearance between the top of the valve stem and the rocker arm
B. compression of the valve springs
C. clearance between the valve seat inserts and the head
D. out of roundness of the fuel injection cams
[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]The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.
A. be jammed
B. be opened
C. be seated
D. be broken
[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
