A.performanceB.horsepower outputC.fuel consumptionD.sca……

单项选择题Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits may cause （）.

A.low compression pressure
B.increased piston wear
C.increased cylinder lube oil consumption
D.poor contact between compression rings and liner

单项选择题In describing engine operation, what does the term “cycle” mean?（）

A.The sequence of events that produce a power pulse
B.One rotation of the engine crankshaft
C.One stroke of a piston
D.All of the above

单项选择题An advantage of aluminum pistons, when compared to cast iron pistons is （）.

A.greater high temperature strength
B.better heat conductivity
C.greater weight per cubic inch
D.increased resistance to wear

单项选择题Which of the combustion parameters listed is used in a diesel engine, but NOT related to the injection system?（）

A.Atomization
B.Metering
C.Effective stroke
D.Penetration

单项选择题Successful combustion inside the cylinders of a diesel engine is dependent upon （）.

A.fine atomization
B.high temperature
C.good mixing of fuel and air
D.all of the above