单项选择题
A.it is dirty B.it is leaky C.it has been renewed D.all the above
Increased air （） will raise scavenge efficiency and all...
单项选择题Increased air （） will raise scavenge efficiency and allow a greater mass of air to be compressed； more fuel may now be burned giving an increased power.
A.specific volume B.density C.viscosity D.calorific value
In the suction stroke air is induced into the cylinder ...
单项选择题In the suction stroke air is induced into the cylinder （）In the compression stroke the air is compressed.
A.by an fuel valve B.through an inlet valve C.with an exhaust valve D.from an outlet valve
In the sentence “In some designs the cylinder oil is ti...
单项选择题In the sentence “In some designs the cylinder oil is timed so that the oil injects only on the piston ring belt, the "piston ring belt" means （）.
A.piston crown B.piston ring groove C.piston skirt D.piston ring area
