单项选择题
A.transfer heat from the cylinder to the piston
B.scrape oil from the sides of the piston
C.seal the combustion space from the crankcases
D.prevent any piston contact with the cylinder liner
单项选择题 An indicator card or pressure-volume diagram, shows graphically the （）
单项选择题 In a single acting, two-stroke/cycle, diesel generator engine, the power impulse in an individual cylinder occurs （）
单项选择题 Modern marine diesel engines equipped with mechanical fuel injection operate on a combustion phase within the cycle which is（）