单项选择题
In the two stroke diesel engine, it is designed so that the oil impingement is timed to proceed only on the piston ring belt during（）
A.compression stroke
B.suction stroke
C.expansion stroke
D.exhaust stroke
相关考题
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单项选择题
One advantage of a flash distilling plant when compared to a submerged tube distiller is（）
A.greater distillate purity through high temperature evaporation
B.cold shocking for scale removal is not required
C.less internal corrosion because of lower brine density
D.less feed-water is required for equal plant capacity -
单项选择题
Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of （）
A.refrigerant bubbles in the lube oil
B.refrigerant reducing the lube oil viscosity
C.oxidation of the lube oil from overheating
D.reducing the floc or cloud point of the oil -
单项选择题
Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?（）
A.Cooling the air to a temperature just above dew point
B.Heating the air to a point at which moisture will boil off ,then re-cooling it
C.Cooling the air to a point below dew point, then reheating it
D.Heating the air and then cooling it to a point below dew point
