试题二十四
一、单项选择题：
1.Bedplates are the ______of the engine, without the support of which the shaft alignment in
particular, and engine structure as a whole, would inevitably be lost.
A. hull
B. projection
C. graphitication
D. foundation
2.Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?
A. Exhaust and scavenging.
B. Scavenging and compression.
C. Ignition and expansion.
D. Exhaust and compression.
3.Which of the following may lead to the engine NOT to start on air?
A. starting air pressure too high.
B. correct timing of starting air valves.
C. three of the six starting valves stuck..
D. the turning gear disengaged.
4.The lowest temperature required to cause self-sustained combustion of a substance
independent of any outside source of ignition is called ______.
A. explosive range
B. flash point
C. ignition temperature
D. combustion
temperature
5.The function of a lubricating oil is ______to lubricate the running surface ______to carry
away a great deal of heat.
A. not/but
B. neither/nor
C. either/or
D. not only/but also
6.The degree to which the viscosity of an oil will change with a change in temperature is
indicated by the ______.
A. weight designation
B. viscosity index
C. pour point
D. thermal change
value
7.All three systems have the ports____to swirl the incoming air and direct it in the appropriate
path.
A. angled
B. rounded
C. being angled
D. being rounded
8.Scavenging in a four-stroke/cycle diesel engine occurs during the ______.
A. last part of the exhaust stroke, and the first part of the intake stroke
B. last part of the intake stroke only
C. early part of the injection stroke only
D. early part of the power stroke
9.______in what position the engine stops there will always be at least one of the cylinders
with its starting air valve open to admit compressed air to start the engine.
A. Because
B. Owing to
C. For
D. No matter
10.The process to remove exhaust gases by blowing in fresh air is called ______.
A. charging
B. supercharging
C. starting
D. scavenging
11.Some vessels are equipped with a water lubricated stern tube. When at sea, operating under
normal conditions, the water service valve from the ship's saltwater system to the bearing should be ______.
A. closed, and no leakage permitted across the shaft packing
B. closed, and only slight leakage permitted across the shaft packing
C. opened, and no leakage permitted across the shaft packing
D. opened, and only slight leakage permitted across the shaft packing
