coming up from the BDC
coming up from the TDC
coming down from the BDC
coming down from the TDC
第1题：
If fuel injection to a four-stroke/cycle diesel engine begins earlier than designed, ignition may be delayed because the
A.cylinder compression pressure may not be high enough
B.cylinder compression temperature may be too high
C.fuel oil injection pressure may not be high enough
D.scavenge and purge process is incomplete
第2题：
less even torque
higher cylinder head temperatures
fewer power strokes per revolution
greater weight/size requirements
第3题：
Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because________.
A.The direction of pressure on the journal in four-stroke engine is continuously
B.positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
C.four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
D.Low-stroke engines usually consume less lube oil than four-stroke engines
第4题：
open
uncover
covered
closed
第5题：
supercharging
scavenging
turbulence
swept volume charging
第6题：
once every crankshaft revolution
once every two crankshaft revolutions
once every piston stroke
twice every piston stroke
第7题：
up and draw in a fresh air charge
down to burn off fuel
down to compress the fuel air charge
up and force out the exhaust gases
第8题：
If all other conditions such as bore, stroke, speed, and mean effective pressures are equal, a two stroke/cycle diesel engine will develop approximately
A.the same indicated horsepower as a four-stroke/cycle engine
B.twice the indicated horsepower as a four-stroke/cycle engine
C.one half the indicated horsepower as a four-stroke/cycle engine
D.one power stroke for every two crankshaft revolutions
第9题：
shut
closing
opened
closed
第10题：
insufficient lubrication
improper piston cooling
blow-by
overload operation