单项选择题
A.reduce fuel weight B.increase specific gravity C.separate fuel from lube oil D.reduce fuel viscosity
In a diesel engine, blow-by is generally the result of ...
单项选择题In a diesel engine, blow-by is generally the result of worn（）
A.valve guides B.oil control rings C.valve seats D.compression rings
For optimum results, centrifugal purification of heavy ...
单项选择题For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable（）
A.throughput B.additive percent C.cetane number D.TBN number
Diesel engine piston ring blow-by is usually caused by ...
单项选择题Diesel engine piston ring blow-by is usually caused by excessive ring clearance at the ring（）
A.back B.side C.gap D.bottom
