improve fuel economy
increase the air charge velocity
reduce the risk of explosion
all of the above
第1题：
Headway
Sternway
No way on，with engines stopped
No way on，with engines full ahead
第2题：
can be started at low temperature and are free from preheating
usually are preheated by steam before being started
are kept at a constant temperature and free from preheating
are kept at a low temperature to save energy
第3题：
An efficient seal between the cylinder block and cylinder heads on many diesel engines is obtained with________.
A.graphite packing
B.sealing compound
C.lubricating oil
D.gaskets
第4题：
antiknock characteristics
ignition qualities
rates of vaporization
viscosity
第5题：
they are more heavily built
the fuel used is less volatile
they can be easily reversed
they operate at a lower speed
第6题：
less even torque
higher cylinder head temperatures
fewer power strokes per revolution
greater weight/size requirements
第7题：
chromium plating piston rings
knurling the piston skirt
extended maximum power operation
applying load to a cold diesel engine
第8题：
All diesel engines are classified as ______．
A.Four cycle
B.Compression ignition
C.Vacuum ignition
D.External combustion
第9题：
Diesel engines have more advantages in comparison with gasoline engines
Diesel engines have more advantages in comparison to gasoline engines
Gasoline engines have more advantages in comparison with diesel engines
Gasoline engines have more advantages in comparison to diesel engines
第10题：
scavenging action of the piston
piston type vacuum pump taking suction off a differential manometer
gland exhausting manometer
crankcase exhaust fan