单项选择题
A.control fuel injection time more precisely
B.control fuel injection rate more precisely
C.meet the environmental requirements
D.meet high engine speed requirements
单项选择题 To meet the market requirements, a marine diesel engine should not be of（）
单项选择题 The common rail engines show great advantages in combustion especially（）.
单项选择题 A common rail engine has only one or two high pressure pumps in operation at the same（）time, and the injection into each cylinder.